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Energy Efficient TABU Optimization Routing Protocol for WSN Protocolo de enrutamiento de optimización TABU de bajo consumo de energía para WSN Protocolo de Roteamento de Otimização TABU com Eficiência Energética para RSSF

Artículo de investigación. https://doi.org/10.16925/2357-6014.2020.03.07 1 IKG PTU Regional Centre, Jalandhar (Punjab), India Orcid: https://orcid.org/0000-0001-7965-6552 E-mail: barkhabright@gmail.com; varsha.548@ctgroup.in 2 Khalsa College of Engineering & Technology, Amritsar, (Punjab), India. Orcid: https://orcid.org/0000-0002-2752-685X E-mail: drmanju571@gmail.com 3 DAV institute of Engineering, Management & Technology, Jalandhar (Punjab), India. Orcid: https://orcid.org/0000-0001-9598-0280 E-mail: drmanojkumarindia@gmail.com 4 DIT, BBAU (A Central University), Lucknow, India. Orcid: https://orcid.org/0000-0002-2126-2830 E-mail: req.mrt@gmail.com Energy Efficient TABU Optimization Routing Protocol for WSN

INTRODUCTION
Routingis a testing issue in the structure of WSNs, can greatly conserve energy and can also improve the network's life [1], while heterogeneity in WSNs can enhance the quality and time. Here, information sent from the transmitting node to the receiving nodeby lessening the over-head and increasing the throughput is the primary aim of routing. Developing a routing technique for WSNs is extremely critical. The realization of power saving to attain the green networking is the main objective of this paper. Many energy efficient clustering techniques for WSNs were introduced in the past such as SEEC, MSEEC [2] and CBCCP [3] ones, but these studies have not scrutinized the proper arrangement of the nodes to make the protocol more energy efficient and stable [4,5].In the literature of MSEEC, there exists a lack of study to investigate the proper arrangements of different nodes viz. normal, super and advanced nodes and put forward an innovative routing scheme. In order to overcome this limitation, we address the case ofa network formation model which is deployed in the network.
This launches the heterogeneity feature in the network and makes it more extensible.
After that,a cluster formation procedure is introduced which depends upon the higher energy factor of the node and makes the network smooth on the way to WSN. On the contrary, a data transmission procedure is executed, which uses a novel approach towards clustering and routing via the TABU search mechanism for the optimization of energy parameters. The simulation results of this scheme aremore lithe and efficient compared to traditional WSNs [6][7][8].
Our contribution to this work can be summarised in the following order: 1. Network formation for the deployment of nodes is mentioned here. This structure has a network scalability feature and extends up to the 500m×500m level. For energy efficient communication, direct communication between the Normal Node (NN) and Super Node (SN) and alsobe-tweenSNand AdvancedNode (AN) is provided.
2. Consideration to the optimization problem in the proposed scheme with respect to load balancing and energy consumption for the implementation of an effective and scalable network. Thus, TABU-MSEEC is proposed under the influence of cluster formation and data transmission to solve the optimization dilemma. This approach is related to the implementation of the green network.
3. With extensive simulations using a random placement of sensor nodes, the suggested technique outperforms the traditional WSN schemes and are observed to be progressively supported for different applications of WSN.

The proposed scheme is as follows:
In this convention, NNs, ANs and SNsare utilized depending on their underlying initial energy. ANs have α times and SNs have β times more energy than the NNs. The members of the cluster will send information to advanced and super node's cluster heads. After receiving the frames from the cluster member, the aggregation operation Ingeniería Solidaria e-ISSN 2357-6014 / Vol. 16, no. 3 / 2020 / Bogotá D.C., Colombia Universidad Cooperativa de Colombia is performed to reduce the excessinformation.From that point onward, the information will be sent to the sink.The novelapproach to this paper is with regards to cluster formations for sensor nodes and data transmission procedures to reduce power consumption and to improve the lifetime of the system. The procedure comprises two stages: during the first stage, the cluster formation is made on the basis of the average residual powerin the node. The average residual energy ofthe Cluster Head (CH) node is more prominent than the residualpower in the node in the system and in the second stage a 2-opt method is generated using the TABU search mechanism, which is a noteworthy criterion for routing. In this work, MSEEC protocol using the TABU search mechanism has been recommended which is a strategy with a more elevated heuristic quality for taking care of optimization issues. It can discover the ideal and close ideal answer for issues. Lots of studied have proposed routing techniquesfor saving nodal energy and improving the routing in WSNs. In this work,we address the matter of routing in WSNs utilizing the TABU search with the aim of maximizing the system lifetime. Initially, a new MSEEC protocol using the TABU search for routing in WSNs with the aim of maximizingsystem lifetime in networks of the order of 200m × 200m is proposed.
The rest of the manuscript is in the following order: Section 2 examines the related work. Methodology has been described in Section 3.Section 4 shows thenetwork and procedures utilized.Section 5 depicts the results and discussion. Finally, Section 6 concludes the paper with future directions.

RELATED WORK
The available studies have discussed the applications and limitations of the networks.
It has also given basic ideas of the functioning of the routing mechanisms and optimum low energy framework of the sensor nodes.
Vijayalakshmi et al. [9] have discussed the identification of optimum paths for routing that enhancethe life-time and decrease the power that is consumedby the network. Results showthat the efficiency of the TABU-PSO is increased by improving the formation of cluster heads, the ratio of active nodes and decreasing therate of mean packet loss, but in the paper the parameters are limited depending on the formation of network chosen. Kaur et al. [10]have proposed a hybrid data aggregating technique known as ACO/PSO,which improves the aggregation of data between the clusters.
It is a tree-based algorithm where the selection of CHs iscompletely dependent upon the remaining nodes' energy. The proposed protocol has improved the life of e-ISSN 2357-6014 / Vol. 16, no. 3 / 2020 / Bogotá D.C., Colombia Universidad Cooperativa de Colombia Energy Efficient TABU Optimization Routing Protocol for WSN theWSN over the other techniques but the author has failed to improve the area scalability as the size of network is so small.
Shankar et al. [11]haveexhibited ahybrid approach of a HAS & PSO algorithm for providing better energy efficient cluster heads. These algorithmshaveshown anincrease in residual energy by 83.89% and throughput by 29%when compared tothe PSO algorithm. However, other meta-heuristic optimization techniques make better improvement over the network. Amuthan et al. [12] have reviewed the meta-heuristic techniques which are applied on combinatorial problems. This technique relieves local search methods from the local optima problem and finds the solution from a single point which is fitted in all the aspects of computer science including VANET, software development effort estimation etc, but has not been implemented with TABU. V.Raghavendranet al. [13] have portrayed the system routing research is Swarm Intelligence (SI) which links to the complex behaviour which emerges from exceptionally straightforward individual conduct and communication that is seen naturally, particularly with social flies, for example, honey bees, ants and so forth. Every individual has little knowledge and pursues the essential guidelines utilizing nearby data adjusted from nature. Ants directing is an essential instrument from SI and gives a proficient arrangement. Fifi et al. [14] exhibited the two energy-effective grouping convention, which utilized the ideal number of energetic nodes that accomplishes the base energy utilization for the system. The M-SEEC is a heterogeneous convention and drags out the soundness time frame, expands the energy effectiveness or more normal throughput.
Tandon, Ravi et al. [15]have devoted their efforts to progressively bunched heterogeneous sensor systems. They uncovered that the presented heterogeneity aware conventions could not disperse the utilization of energy consistently. The paper has proposed Cluster Re-election Protocol (CRP),that is aware of heterogeneity and upgrades the system dependability time over prevailing conventions.Shilpaet al. [16] proposed an energy balanced cluster head selecting strategy based on QoSfor WSN, which provides the weight selection method of CH known as Cluster-Chain Weight Metric approach (CCWM) for improving theeffectiveness of the entire network. With this approach the conservation of energy of sensors and load balancing takes place.
Our objective in this paper is to select appropriate cluster headsby enhancing the quality of routing in HWSNs by lessening the general energy utilization, expanding the security time of the system and extending the system lifetime. The summary of work performed by various researchers in the past is given below:  clusters transmit the information stored in the sensors to the CHs. Once a CH gets information outlines from the clusters, the collected information is evaluated to eliminate any excess information. At that point, CHs transmit the collected information to the BS. Although a static environment is good, such type of environment is failed in heterogeneous conditions because all sensor nodes are fixed;hence it is an energy efficient protocol but it suffers from the heterogeneity of a routing protocol. If the Super Node (SN) which acts as a Cluster Head (CH) dies or fails, the whole network will collapse.If a Super Node dies, then a Normal Node will directlycommunicate with an Advanced Node(AN) and energy consumption will be high which will reduce the network lifetime of a network;the whole network is Static and it also causes flooding at the sink or base station.

Network Model
An energy-efficient communication environment has been formalised as illustrated in Figure  in which the base station is stationary and normal nodes are also static. In Figure   1(b) the nodes are changed after each round and SNs are located at a distance R2

Energy required for the Network
The nodes must be identified for evaluating the entire energy of heterogeneous systems with three levels.M AN of ANs has an initial energy of (1+α) E 0 . Similarly, M SN of SN's has an initial energy of (1+β ) E 0 and n1 of NN hasapreliminary energy of E 0 . So the entirepreliminary energy required is In this manner, the three-level M-SEEC has (α .M AN +β. M SN ) times more energy.

Total quantity of rounds in the network
It is necessary to compute the total quantity of rounds in the lifetime of the network for all three kinds of node for evaluating the required energy of that system.In the fol-

Improvised Energy Efficient TABU Optimization Routing Protocol
In the first case, an improvised TABU optimization routing protocol that has high energy efficiency has been proposedfor WSN in the presence of node heterogeneity with the routing done by TABU search in the stable environment. In this,the threekinds of nodes areon the basis of their energy value in the initial stage. The position of ANs and SNs are fixed but the position of NNs is not fixed.M SN, which represents the super node, is the ratio of the nodes having α times higher energy than NNs to the total nodes. The rest of the nodeshave energy E 0 . P=p1+p2 where p1 is the overall number ofNNslinked to ANs and p2 is the overallNNslinked to SNs.The overall energy of the triple layered networks is represented by: Therefore, the three-level M-SEEC has (α .M AN +β. M SN ) times more energy.

=
The nodes are spread in the network in a random manner and every group has a cluster head.

AsLength * Breadth >> ×
The optional length of the path from the node in uppermost cell to the bottommost cell is by using Euclidian distance.

= ×√
The meanpower consumed by the nodes in every cluster is represented by

Level of heterogeneity
The level of heterogeneity is represented by the given formula that is

Optimumcount of ANs
The amount of power that is consumed at the time of single transferis expressed by following condition (18) E AN = n A . L. E elec + n A .L. E DA +L. E elec + L. e fs .R1 2 Where E DA represents the data aggregation cost and R1 represents the distance between advanced node and base station. The energy utilized by normal nodes is expressed by the following equation

ALGORITHMS UTILIZED
These are several algorithms/procedures developed and utilized to reach our objectives.These algorithms are given below:

Network Formation Procedure
The TABU-MSEEC model considers a structure made out of a predefined quantity of nodes placed discretionarily in a testing area. The entire group of nodes have a starting energy that is proportional to E0. In the proposed estimation, 3 stages are invoked.
The first stage is a network formation procedure where the roles of different nodes are selected. The accompanying stage is the cluster formation procedure and this is where the clusters are formed. The last one is the data transmission procedure, where the routing is done via the process of theTABU algorithm.
Step 2: The AN is situated at a location that is R1 units away from the BS. Step 3: The SN is located at a position of distance R2 with respect to the remaining area(M2×M2)-(M1×M1).
Step 4: The normal nodes are randomly deployed.

Cluster Formation Procedure
Once the network model is fixed, the next aim is to identify the cluster head from the entire network. A CH should be selected on the basis of their highest energy parameter. Since all the sensor nodes have extremely restricted energy, the CH must gather all the node data and after that, forward it to the sink;the rest of the energy of the node ought to be viewed while picking the CH. Thechoosing process of the CH is as follows:

Cluster Formation Procedure
Step 1: As per the directions of the nodes in every locale, the focal point of locale's gravity is determined. This point (X f ,Y f ) ought to be correspond with the slightest square and least separation of nodes in the network, and the following formula is used. ) ) (X f ,Y f ) = min N Where(X f , Y f )is the direction of every node; Step 2: The distance between the nodes and its focal point of gravity is obtained by equation d= ) ) Step 3:Compute the normal remaining power in the nodes of every group.

Now, E rem at time t is calculated by utilisingexpression E rem = E i -E (t)
Step 4: If the remaining energy of the nodes is more prominent than every node in the mean residual energy, then that node is chosen as the head. If not, then the next node is compared. A sensor node whose energy is more prominent than the mean remaining energy is identified as the CH.

Data Transmission Procedure
In the TABU-MSEEC protocol, the TABU technique is employed in order to make the network more energy-saving. A cluster in the network is chosen on the basis of its energy parameter and these clusters gather details from their members and send it to the sink [17,18]. For the transmission phase, the TABU technique is used, which makes the network more methodical and reliable. In order to perceive the optimal solution,the initial solution is produced by the TABU search achievably and simultaneously.The inceptive solution becomes the best solution and the current solution is placed in the TABU list which is the memory list and is usedinorder to avert the cycling. The first selected element in the list is replaced by a novel oneif the existing list is already filled. Step 2: In order to producethe neighbourhood solutions, the 2 opt method is utilized which is performed by swapping the position of two randomly selected solutions. By doing so,"n*(n-1)/2" sequences are generated. The framework is initiated with a randomly generatedpreliminary solution and travels from one neighbour to anotherwhile continuously altering the value of the objective functions. E.g., let the initial sequence be (1,2,……a,…b……n).After exchanging the positions of the two solutions, the newly obtained sequence will be(1,2,……b,…a,….n), which will become the new solution for every iteration in the list. Step 3: In accordance with the aspiration criteria, the neighbourhood solution is found and the current solution is then amended in the TABU list. If the solution is good when compared to the existing optimum solution, then it is updatedin the list and the solution is monitoredto verify if itis a TABU. If it is, then choose the next ideal solution and if it is not, then the existing oneis updated as the present solution and updated in the list.
The process of steps from 1 to 3 is repeated with a specific iterated step and the lastvalue of shortest route among the entire network is given as the output.

Begin
Select a preliminary solution i in solution space. to be dead when their energy parameters value is zero. For the evaluation, the radio energy model that was proposed byHeinzelman [21] is utilised. Results of MSEEC arerelated with TABU-MSEEC protocol.They are assessed on the basis of these parameterswhich are mentioned below in Table 4.  On applying the TABU search mechanism, the following results are obtained. For the simulation,the MATLAB 2013a tool is used for easy computing of results.All results were compared with the basic multi-level protocol which has high energy efficiency and stability. The performance metrics used in the results show that the proposed TABU based MSEEC protocol is stable for a longer time,has higher energy efficiency and higher throughput when compared to basic multi-level clustering protocols. For simulation, we analyse the results based on two conditions i.e. with static nodes and moving normal nodes with each round.

Evaluation of MSEEC and TABU-MSEEC in terms of alive nodes
It is the amount of individual types of nodes and also the aggregate amount of nodes which has not used their entire energy.This measurement demonstrates the entire lifespan of the system. All the more essentially, it providesa portion of the covered area  Hence, it may be concluded from the comparison in Table 1that the optimum results are obtained when the energy value of nodes is increasing. This also indicates that TABU-MSEEC has more valuable results than the MSEEC protocol.  Similarly, for TABU-MSEEC, FND begins at around 3050 rounds, whereas LND begins at around 17000: because the TABU takes time to find the best solution initially.

Evaluation of MSEEC and TABU-M-SEEC in terms of dead nodes
The performance of MSEEC and TABU-MSEEC protocol is also determined on another parameter; dead nodes. Here, the dead node parameter is calculated among NNs, ANs, SNsand the total nodes in the network.  This is because the advanced nodes and super nodes lose their lifeslower than the normal nodes.

Evaluation of MSEEC and TABU-MSEEC in terms of throughput
Throughput is the amount of data packets which are obtained at the sink. It is considered as the totaldata which is transferred through the network, the total data sent from ANs or SNs to the BS. It can also be considered as the total data sent from the NNs to the ANs and SNs.When the proposed protocol is compared with existing protocol, it can be seen that the proposed protocol shows improved throughput.  received at the BS. The network's lifespan is goodwhen the death rate of the nodes is less and vice-versa. When the alive nodes are high, it will send more data to theBS.
It has been shown that TABU-MSEEC proved to be better than MSEEC. In MSEEC,the packets which aresent to the BS is at 12050 rounds while for TABU-MSEEC it is after 17000 rounds.

Evaluation of MSEEC and TABU-MSEEC in terms of remaining average energy
It is the amount of energy left with sensor nodes. It is computed in the beginning of each round during execution of the algorithm. This parameter helps to determine the stability period, consumption of energy and lifetime of WSNs. The residual energy is a major parameter to be considered for WSNs, that is calculated using Where E rr (Nd) is the energy of Nd th node for n th round.
Here,it is seen from the results that the average energy consumed is around 2200 rounds in MSEEC, whereasforTABU-MSEEC, it occurs even after 3500 rounds in the case of NNs.In the case of ANs, the average energy consumed is after 7500 rounds in MSEEC,while it occurs in the case of TABU-MSEEC even after 11500 rounds.
In the case of super nodes the average energy consumed is after 12000 rounds in MSEEC,while it occurs in the case of TABU-MSEEC even after 17000 rounds.Here, the observations reveal that the performance of TABUsearch is very high when compared to the MSEEC protocol because TABU search chooses the most effective solution.

CONCLUSION AND FUTURE DIRECTIONS
The TABU-MSEEC protocol presents an improvement over the MSEEC protocol. The method adopted for transmission is governed by the candidate solution of the TABU.
If the proposed solution has greater effectivenessthanthe existing optimum solution, then it is updated into the TABU list and the solution is judged to be a TABU.If it is TABU, then the 2 nd best solution is selectedfor the steps and if it is not TABU, then the solution is updated as the existing solution and the TABU list is updated. This approach may lead to a greater stability period and makes the network more efficient.
The proposed techniqueis better than the existing one since the remaining energy in the network is increased by 62% compared to normal nodes in MSEEC, 65% compared to advanced nodes in MSEEC and 70% compared to super nodes in MSEEC.
The network lifetime is also enhanced by 70.8% when compared to MSEEC. The simulated results shows the improvements of TABU-MSEEC over MSEEC. The FND is delayed by 1450, 1950 and 3500 rounds in NN, ANand SN respectively. Also, the LND is delayed by 100, 4200 and 5000 rounds in NN, AN and SN respectively. As a future work, the gathered data can be utilized to decide the impact of the path loss in applications that rely upon RSSI and the path loss exponent, for example, RSS-based confinement and energy analysis and also work on clustering and routing with other bio-inspired algorithms like cuckoo search, flower pollination, spider monkey optimization, Glow-worm and Meerkat Clan Algorithm.


Technology-enhanced Auditing in Voluntary Sustainability Standards: The Impact of COVID-19

: The ongoing COVID-19 pandemic has had a significant impact on the certification and auditing services of Voluntary Sustainability Standards (VSS). The traditional approach to auditing—on-site visits—has been significantly curtailed, and it is unclear when, and under what conditions, it might resume in full. The purpose of this paper is to study the initial responses to COVID-19 of leading VSS—a group of 21 standards that are members of ISEAL, a global membership organization for VSS. This is a qualitative study, and data are collected from publicly-available sources (i.e., official announcements, policy amendments, derogations) in order to inductively analyze how individual VSS have adjusted their certification services in response to travel bans and lockdowns. The emphasis of the analysis was understanding the role of technologies in the VSS responses to the COVID-19 crisis. The findings demonstrate significant uptake of remote auditing and information and communications technology (ICT), even though that uptake is constrained by limiting conditions and it is not currently expected by VSS to extend beyond the crisis. Lessons learned from the crisis are discussed, and the potential for remote auditing during this period to encourage the adoption of more advanced technologies (such as artificial intelligence and satellite monitoring) in certification services is explored. A set of research questions to guide future work grounded in the analysis is also provided.

Introduction
The COVID-19 pandemic has spread across the globe with devastating human and economic consequences [1]. The pandemic has changed the everyday habits of people around the world, and the new realities of lockdowns and social distancing have accelerated the uptake of technologies. The demand for communication software such as Microsoft TEAMS and ZOOM has been unprecedented [2], as hundreds of millions of people have abruptly been required to work remotely from home.
As countries begin to reopen their economies, the early signs suggest that these business practices have already reshaped the 'new normal' in the aftermath of the pandemic. For instance, reports from China after its reopening suggest that the way people work is likely to change; new office designs now accommodate rules requiring "six feet" of social distancing, and more corporations are integrating remote working into their daily operations. Importantly, multinational corporations that operate in China (e.g., VW, Starbucks) are scrutinizing the restart there to adjust their operating practices in countries that have not yet reopened [3]. The responses so far suggest that the pandemic is likely to accelerate the adoption of new operational practices, including the adoption of technologies. In this paper, the impact of COVID-19 on the adoption of technologies is investigated in the context periodic third-party surveillance audits to ensure the organization remains in conformance with the requirements over time. The analysis is based on data from a set of leading VSS that was collected from publicly-available sources (official announcements, policy amendments, derogations or similar; up to April 30, 2020). The analysis of the responses serves as a springboard to discuss the research question, focusing on what the crisis will mean for the future of VSS and to what extent the crisis will accelerate the uptake of new practices, such as remote auditing or more advanced forms of technology-enhanced auditing [11].
Studying the impact of COVID-19 in the context of VSS and how those VSS have adopted technologies for auditing in response to the crisis is important for several reasons. First, the idea of remote audits has been developing in accreditation and certification services for some time. Yet the uptake of these practices has been slow [12,13]. VSS are generally seen as lagging behind technological trends [14], and, as Herding and Fischer (2015) observe, the "underlying certification process nowadays remains remarkably similar to 20 years ago." Some VSS have been exploring technologies, while accreditation bodies have been defining the circumstances and considerations under which ICT may be used. For instance, the International Accreditation Forum produced IAF MD 4:2018, a document explaining the use of Information and Communications Technology (ICT) for auditing and assessment purposes [9]. The ISEAL innovations fund has also supported many projects exploring the increased use of technology in VSS [15]. It is interesting to study whether VSS have adopted technologies for auditing in response to the pandemic and whether this is viewed by VSS as a temporary measure or something potentially more lasting. Second, organizational responses during crises (caused by exogenous shocks such as natural disasters [16,17]) provide insights into organizational resilience [18] as well as into the future restructuring of industries and operating practices [19]. Moreover, there is very little research to address the role of IT in organizational resilience [20]. The COVID-19 pandemic therefore provides an interesting empirical setting to study the adoption of technologies in auditing. Third, VSS are representative of other certification and accreditation areas, for instance, the ISO 9001 certification for quality management, which is the world's most widely-applied voluntary management system standard. ISO 9001 and other ISO standards share many governance principles with VSS, such as a common standard as a reference point, audits by arms-length third parties, and oversight by accreditation bodies. Moreover, in April 2020, ISO and IAF produced guidance on remote audits that aligns with the practices discussed in this paper in the context of VSS [10]. Studies on VSS and their use of technologies in auditing can therefore have implications for a very broad set of standards, certifications, and accreditation that are essential mechanisms for international trade [21]. The paper thus provides important contributions with respect to studying the adoption of remote audits in widely-used VSS in the empirical setting of the emerging COVID-19 crisis.
The article is structured as follows. In Section 2, VSS and the underlying principles of VSS' operations, including the auditing function and the uptake of technologies for auditing, are discussed. In Section 3, the data collection process and data analysis used in this study are explained. In Section 4, the data analysis is provided. In particular, the analysis focuses on the introduction of remote audits, the guiding principles, and key challenges that emerged during the early stages of the crisis. In Section 5, the paper discusses the long-term implications for auditing practices in VSS and contribution to the literature. This section also provides key questions to guide future research in this area. The paper concludes that the crisis has accelerated the uptake of remote auditing and that VSS need to continue to embrace the principles of technology-enhanced auditing.

Background
As noted earlier, Voluntary Sustainability Standards (VSS) are a "collective of organizations responsible for the activities involved in the implementation of a [sustainability] standard, including standard-setting, capacity building, assurance, labelling, and monitoring and evaluation." There are other terms that are used in the literature, such as sustainability standard-setting organizations (SSOs; [14]), eco-labelling schemes [22], or eco-labels [23]. In the literature that focuses on policy development, the term VSS is used more frequently, as, for example, in a report by the International Institute for Sustainable Development [24] or in the report by the United Nations Forum of Sustainability Standards [25]. The key attributes of VSS are that they are led by private actors (NGOs, firms, or industry consortia; [5]) and that they use information (typically certification/labelling) to create market incentives for sustainable production [25].
There are many reasons why companies choose to obtain VSS certification or why customers consider them in their purchasing decisions [26,27]. From a theoretical perspective, VSS serve as a mechanism to reduce information asymmetry [28] in the domain of sustainable products and provide a signal of a usually hidden sustainable attribute of a product [29,30]. For instance, the FSC label on outdoor furniture indicates that it was manufactured using wood sourced from a sustainable forest. The critical aspect of signaling is the credibility of the signal [28]. Credibility in the context of VSS is manifested by their governance of standard-setting, implementation, monitoring, and labelling processes [4,[31][32][33]. VSS are typically developed through a multi-stakeholder consultation process, in which "the expertise, skills and finance of non-profit and for-profit organizations are pooled" [34]. Similar to all multi-stakeholder initiatives, the credibility of VSS rests on both their input and output legitimacy [35]. As Mena and Palazzo (2012, p. 536) explain, input legitimacy concerns issues related to stakeholder inclusion, procedural fairness of deliberations, promotion of a consensual orientation, and structural and process transparency. Output legitimacy, on the other hand, is derived from high coverage, high efficacy, and a guarantee of "good enforcement and monitoring of their rules" [35].
Standard-setting is the foundation of all VSS, as their fundamental role is to define the sustainability requirements that organizations have to meet. The credibility of standard-setting is developed through a multi-stakeholder standard development process [35,36], which focuses on building input legitimacy, as well as by formulating reference points that address sustainability in substance focused on output legitimacy. In terms of implementation and monitoring, VSS ensure their credibility by defining the rules of monitoring (auditing) and by creating multiple tiers of governance with other independent institutions. For example, accreditation bodies such as Social Accountability Accreditation Services (SAAS), IOAS (formerly International Organic Accreditation Service), and Assurance Services International (formerly Accreditation Services International) were established in order to oversee organizations that provide certification (i.e., conformity assessment bodies). Moreover, VSS usually determine a set of auditing procedures for an initial audit (i.e., the time when a firm is first certified), surveillance audits (which occur during the period for which a certificate was issued; typically three years), and recertification audits (i.e., when a firm needs to renew its certification for the next cycle). More recently, an increasing number of VSS have started to collect evidence of their impact [37], which is used to further strengthen the credibility of their standards.
The actual governance practices, however, differ across VSS [7], and the credibility of VSS are questioned in academic studies [7,31,38,39]. These credibility concerns are in part related to perceived audit inconsistencies. Although certification bodies typically argue that the audit quality of any of their clients should be similar [40], a number of studies of voluntary standards have shown that this is not the case [41,42]. In studies of widely-used management system standards, such as ISO 9001 and ISO 14001, it has been argued that these inconsistencies can arise, at least in part, from the conflicts of interest between clients and certification bodies [43][44][45]. A key concern is that the clients serve as the "paymasters" [46] of the certification bodies, meaning that the audits are typically "contracted and paid for by the company that wishes to become certified" [47]. Weak auditing regimes can result in unworthy firms receiving certification and erode the signaling power of the certification. Certified firms that have only "ceremonially" adopted a standard [48] can lead to a "decoupling" between the stated and real practices within a certified firm [49], thus damaging a standard's credibility. A key focus of the literature on voluntary standards is the issue of "symbolic" vs. "substantive" implementation [48]. These concerns can partially be mitigated by high levels of transparency in the certification process, and several VSS, such as FSC, MSC, and RSPO, make considerable information regarding their processes publicly available. To help strengthen the veracity of audits, and, thus, granting certification to firms that have only ceremonially adopted a standard, there is a growing stream of literature focusing on the use of technologies to strengthen the credibility of VSS [11,14,50]. Adoption of new technologies is one of the pillars to increase credibility in certification [14].
The certification industry has been pondering the role of information technologies in auditing for a while. For instance, the IAF has included remote auditing in their guidelines on audit time [51], and has also provided a "mandatory document" on the use of ICT in remote assessment [9]. The IAF documents focus on the conduct of a remote audit, where technologies are used in the context of existing audit processes. Essentially, ICT replicates the characteristics of the traditional, on-site, in-person audit process, "where demonstration of evidence, conformity or traceability can be confirmed via electronic means" [8].
There is also a growing interest in the literature on technology-enhanced auditing (TEA). In TEA, technologies are employed to enhance audits rather that replicate traditional auditing processes, with an emphasis on improving the veracity and timeliness of audits [11]. Therefore, TEA aims to improve the mechanics (e.g., improve supply chain tracking) and performance (i.e., consistency of audits) of the traditional auditing process [50]. TEA has emerged as an important issue in managing financial audits [52], non-financial audits in the context of environmental management and social responsibility [11], and as an important strategic resource in supply chain management [53]. It is also increasingly being discussed in the context of VSS [14,54]. At a basic level, remote audits involve technologies such as audio-visual equipment, videoconferencing, or drones, with the desired outcome of essentially replicating an on-site visit. At a more advanced level, technology-enhanced audits can include Big Data and artificial intelligence to enhance what is typically done in a traditional audit. TEA can also help facilitate a shift from retrospective audits to real-time, continuous audits [55]. As part of this study on the response to the COVID-19 crisis, the focus is on remote audits. However, the findings in the broader context of TEA are also discussed.
The above discussion demonstrates that auditing is one of the foundations of VSS credibility. Auditing is particularly critical in enforcing and monitoring the implementation of VSS, such as in distinguishing between certifications that have been substantively vs. ceremonially implemented. There is a growing body of literature highlighting that technology can be used to support and enhance auditing [11,13,14,52]. However, there are few empirical studies that specifically investigate the adoption of remote or technology-enhanced auditing in VSS. Moreover, the COVID-19 pandemic provides an interesting empirical setting to study the adoption of technologies in auditing. During crises, organizations are pushed to their limits to address the crisis and need to demonstrate their ability to resist and respond to a shock and to recover [18]. Often, their response is constrained by restricted resources and under time pressure. In such an environment, novel approaches often emerge [56]. Organizational resilience literature often scrutinizes organizational responses during crises (caused by exogenous shocks such as natural disasters, [16,17]) to provide insights into organizational resilience, as well as into future restructuring of industries. Recent work in the resilience field highlighted the lack of studies on the role of IT in response to disaster [20], which is also addressed in this paper.

Sample
There are numerous Voluntary Sustainability Standards (VSS), though an exact count is elusive. For example, the Ecolabel Index (http://www.ecolabelindex.com), which self-identifies as the "largest global directory of ecolabels" tracked "458 ecolabels in 199 countries, and 25 industry sectors" at the end of April 2020. At the same point in time, the International Trade Centre's Standards Map (http://www.standardsmap.org) listed over "210 standards, codes of conduct, [and] audit protocols addressing sustainability hotspots in global supply chains". This study was limited to VSS that are listed as 'full members' of ISEAL. As it explains on its website [57], ISEAL is a "global membership organization for credible sustainability standards." ISEAL's list of full members includes 22 VSS, which operate in sectors such as forestry, agriculture, and fisheries, among many others. Assurance Services International (ASI), which is an assurance provider, is excluded from this study, leaving a total of 21 VSS. An overview of the members and a basic description of the scope of their activities is provided in the Table A1 in Appendix A. This sample provides a useful setting for this research as these VSS represent exemplars in the certification industry, whose practices are likely to be followed by others in a crisis like COVID-19. These VSS also have the resources to be able to adopt new approaches, including new technologies to support auditing, to ensure the credibility of their operations.

Data Collection Procedure
The data for each VSS included in this study were obtained from their official websites (the links for each website are available from ISEAL's database of full-members). The websites were searched for any COVID-19 related information. Typically, a "COVID-19 Response" link appeared on the VSS's home page. In every case, those links were followed, but search engines were also used with the keywords "COVID-19" and "coronavirus" to make sure that no relevant information was missed.
The search provided several outputs: basic announcements that informed certified firms about upcoming changes, interim policies, and derogations. Some VSS provided information on the broader impact of COVID-19 on the operations of certified firms. For instance, the MSC reported on Samherji, an Icelandic MSC certified seafood company, which offered their employees extended time at sea as a form of quarantine [58]. Other VSS provided information regarding the impact of COVID-19 on international trade and labor-related issues; for instance, Fair Trade International (FT International) provided reports on the impact on major commodities, such as coffee and bananas. Some VSS opted to create support funds to address their clients' critical needs; e.g., Fair Trade USA reported on the increased flexibility of their Community Development Funds [59].
These examples illustrate the range of data collected; however, it is important to stress that the information provided by individual VSS varied widely. While some of the responses to the COVID-19 crisis went beyond the use of remote auditing, the focus of the analysis is on the research question. In terms of data collection for this paper, the focus has therefore been on the impact of COVID-19 on auditing and how individual schemes adjusted the rules governing the certification services of Certification Bodies (CBs) within the VSS assurance program in response to travel bans and lockdowns. All announcements and related policies were downloaded for the analysis.

Analysis
Qualitative analysis was conducted on all collected data [60]. The focus was on understanding the procedural steps taken by VSS and the role of technologies in their response rather than the narrative around those steps (i.e., the focus was not on how the response was framed in the announcements).
The analysis was initially done on a random sample of eight VSS, followed by the analysis of all 21 VSS. The aim of this pilot analysis of eight selected VSS was to explore the data set and to define an analytical framework. The analytical approach was inductive and used the logic on an emerging coding scheme [61]. The analysis was guided by the research question and notes were taken of instances that explain those adjustments. The initial analysis explored if the response was different across VSS and, therefore, whether a comparative analysis of the responses amongst VSS would be helpful. It was observed from the pilot analysis that (a) there was observable difference between the responses (e.g., some schemes offered remote audits; others not) and (b) the underlying nature of the responses were broadly consistent between VSS in cases where remote auditing was adopted. The data contained details on actions taken, including amendments of rules and guidelines on remote auditing, which was in line with the aims of the study's research question.
After finalizing the pilot analysis, the framework for coding of the data of all 21 VSS in the sample was defined (Table 1). Some data are in quantitative form (e.g., # of VSS that allowed remote auditing), yet most of the data are qualitative (e.g., guidance of remote audits). In line with the usual practices in qualitative research [62], the paper provides examples and quotes from the dataset (for instance, quotes from interim policies and or website) as part of the discussion of the findings. The findings section also reports the quantitative findings. What rules and/or advice did the VSS put forward for remote auditing? What were the differences between initial, surveillance, and recertification audits?

Technological guidance
What advice was given about the use of technologies in auditing?
What are the recommended technologies for remote audits? What guidance was provided on the use of technologies? What problems and difficulties were expected?

Policies issued and their content
What policies specific to COVID-19 were produced during the response to the COVID-19 pandemic?
Was there a new policy introduced? What was the validity of the new policy? What were the differences in the content of the policies between VSS?
One observation worth mentioning is that the level of detail provided by VSS varied. For instance, the Forest Stewardship Council (FSC) provided detailed guidelines on remote audits, which were also grounded in IAF Guidelines. The Alliance for Water Stewardship (AWS), on the other hand, provided a short announcement and relied on direct communication with their clients. This is noted in order to highlight that, in this study, the aim was not to evaluate the actions of VSS per se. Moreover, the fact that one VSS provided more (or less) information than another does not necessarily signify the quality of their response. It is possible, for example, that small VSS do not rely on external communication as much as a large VSS, such as the FSC. Another observation worth mentioning is the consistency in the adoption of remote auditing. The overall guidance and underlying principles were fairly consistent. The differences were largely due to the different level of detail that was disclosed. Despite this limitation, the data facilitated the development of an understanding about the response and provided supporting evidence to discuss the impact of the COVID-19 crisis on VSS and, consequently, a discussion of the future adoption of technologies and remote auditing.

Findings
The travel restrictions and lockdowns left the VSS with three basic options: (1) suspend all auditing activities until the restrictions are lifted, (2) introduce remote audits during the crisis, or (3) a combination of both. In general, the move towards suspension or remote auditing was impacted by two factors: (1) a client being in an area of a health risk due to COVID-19 (demonstrated through verifiable public sources; e.g., official travel warnings or restrictions) or (2) the auditors were banned from travelling by internal policies or based on restriction of public authorities at their location.
Only one VSS did not provide any statement on COVID-19, nine VSS opted to suspend auditing without offering remote audits, ten VSS offered remote audits, and one VSS stated that they will consider remote audits. A statement from AWS provides a representative example for the VSS that opted to suspend their certification activities, while also offering an extension of the validity of their certification: "We are providing a two-month extension period on surveillance and re-certification audits to AWS until 1 June 2020. We are continuously monitoring and reviewing the situation and will keep you updated with the latest developments".
In other VSS, the decision to postpone or to audit remotely was considered on a case-by-case basis based on consultations between clients, certification bodies, and the VSS. Overall, 11 VSS permitted remote auditing during the COVID-19 crisis. One additional VSS was open to considering remote auditing on a case-by-case basis, but did not issue a blanket permission for it. The following sub-sections summarize the VSS responses with respect to remote auditing, the use of technologies, and policies amendments during the early stages of the pandemic.

Remote Audits
Within the subset of VSS that allowed for remote audits, the response was broadly consistent. VSS reacted by developing guidelines and rules for remote audits (some VSS refer to remote audits as "desk audits") and initiated remote auditing practices. In many instances, the rules were set in new or amended policies. For example, ASC provided the following in their March 18, 2020 version of ASC Policy for Audits During the COVID-19 Outbreak: "The policy sets out various scenarios including surveillance audits (which must be carried out on an annual basis throughout a farm's certification) as well as re-certification audits and initial audits. In some cases, audits may be carried out remotely, or partly remotely where some, but not all, auditors are able to attend. In other cases a farm's certification may be extended if it is not possible to carry out a re-certification audit within the required timeframe. Further details on these scenarios, the possible options, and the requirements for these options, can be found in the full policy document." As in the ASC case noted above, many VSS have accepted that surveillance audits may be conducted remotely. However, not all VSS decided to permit remote auditing in surveillance audits. For instance, the FSC stipulated that under the following circumstances, a remote audit is not possible (FSC-DER-2020-001): "open major CARs [Corrective Actions Requests], supply chain integrity issues (e.g., integrity investigations involving the certificate holder/production sector or trading species), subcontracting / outsourcing of certified activities in response to the coronavirus outbreak, ongoing complaints" Recertification audits were typically delayed through the provision of an extension and/or replaced by surveillance audits. Remote audits, however, have not been deemed acceptable for initial certification and all VSS, with one exception, opted to postpone the initial certification. In the one exceptional case, ASC permitted the conduct of initial and re-certification audits for applicants in countries listed as low and medium risk (based on ASC's social profile of countries; this is explained on page 8 of the ASC Policy for Audits During the COVID-19).
In some cases, decisions on remote audits were contingent on the types of evidence required to support the audits. For example, the Aluminum Stewardship Initiative defined its rules based on objective and observation evidence (Interim Policy regarding Audits, Audit-Related Travel and Coronavirus; p. 2) "Objective evidence that can be reviewed remotely includes documentation and some testimonials. For example, interviews of management, staff/workers and stakeholders may be possible and appropriate, depending on access to web-based communications (or similar) and the health of the individuals. General principles for interviewing in the ASI Assurance Manual still apply. Objective evidence that cannot be reviewed remotely is observation evidence. Verification of on-site implementation, process control and risk control where relevant in applicable ASI Standards cannot be audited using remote audit techniques." Several VSS offered explicit direction on the steps auditors and certification bodies would need to take in order to maintain the integrity of their audits while they were conducted remotely. For example, the FSC required that all certification bodies must have a "documented policy, procedure, or both, outlining the process to be implemented in case an audit is affected by the novel coronavirus (COVID- 19) pandemic" (FSC-DER-2020-001). Moreover, the FSC was explicit that this must include: "A method for assessing whether an on-site audit can be replaced with a desk audit, A description of the desk audit methods to be applied in the case of Forest Management and Chain of Custody, A process to implement the reporting and record keeping requirements of this derogation." The Roundtable on Sustainable Biomaterials (RSB) established conditions on granting permissions for remote audits, noting that an explicit request was required and it must address the scope of the certification, including detail on the affected facilities, the inputs and outputs being certified, and the documents that would be reviewed (Reactive Guidance on RSB-PRO-70-001: Audit schedule changes due to conditions beyond the control of POs and CBs). The RSB also required submission of a proposed agenda, as well as clarification on the "systems that the auditors will be able to remotely access", accompanied by an assessment by the certification body regarding "whether the documentation and systems to be provided by the operator are sufficient to conduct the audit remotely." Moreover, the RSB noted that, "If the request is granted, and the audit is carried out remotely, the following audit (within 12 months of the issuance of the certificate) shall be an on-site audit." Some VSS, such as the FSC and ASC, also established specific provisions for establishing auditors' competence. In these cases, there appeared to be a recognition that auditor competence was considered transferrable between on-site and remote audits. The ASC, for example, required (ASC Policy for Audits During the COVID-19 Outbreak): "The auditors (remote or on-site) shall have conducted at least two ASC audits in the standard that they are auditing in the same role (lead or social auditor). These two audits shall have been conducted after auditor's sign-off by the CAB. Shadow audits for initial approval shall not be considered." Their actions show that many VSS recognized the need for extraordinary action during the early stages of the COVID-19 crisis and that an increased openness to remote auditing was a foundation of their responses. However, the imposition by many of the VSS of conditions on remote auditing may also indicate that they are not yet fully comfortable with it as a replacement for traditional on-site, in-person audits.

Use of Technologies
There was a broad recognition amongst the VSS that technology could help facilitate the shift to remote auditing during the COVID-19 crisis. The use of information and communications technology (ICT) was frequently cited as a means of collecting and verifying audit evidence. In the ASC Policy for Audits During the COVID-19 Outbreak, for example, the ASC noted several potential uses of ICT in remote auditing, including (but not limited to): " Teleconferencing using video and/or audio Sharing of data Assessment of documents through remote sharing, teleconferencing or other means Video and/or audio streaming from remote locations Records of video and/or audio and/or video stills and/or screenshots." FSC provides another example of a VSS that recognized the need for increased use of ICT, noting the need to use virtual meetings for stakeholder interviews, but also recognizing the possibility of using satellite images where possible. The use of satellite imagery for monitoring forestry coverage, for example, has previously been noted in the literature [63], and underlines that the type of technology used in remote auditing can vary between VSS. Moreover, the VSS generally recognized the possibility of both on-and off-line ICT options.
Notwithstanding those points, the VSS did broadly recognize that technology is not a panacea and a number of technical difficulties were possible. For example, in a question and answer document posted on its website (FAQs -Coronavirus-related changes in FLOCERT's [which manages certification for FT International] operations), FT International acknowledged the potential unavailability of good internet connections, something which may be particularly pronounced in developing countries. This could lead to the postponement of an audit: "[Question]: Our Internet connection is not very good and/or we do not have access to all the technology needed. What should we do in case we cannot hold the audit remotely due to these technical problem(s)?
[Answer]: Of course, technology and especially a stable internet connection that allows for a transfer of documents and information is key for the remote audit. In the preparation and scoping call with the auditor please raise and discuss all challenges you might face in this regard. Generally, different options to perform the remote audit are possible: The live interaction with the auditor is ideally done via a web-based audio or video tool. In case teleconferencing is not possible due to poor internet connection, a live interaction via telephone is an option or even via an instant e-mail exchange on an agreed date. In any case, the auditor will try to accommodate your preferred option. If the auditor realises that none of the previous options are realistic, we may need to postpone the remote audit, and this decision will then be conveyed to you thereafter." In any case, it was also recognized by some VSS that technology would not necessarily provide all of the evidence required for a remote audit. As the representative example from Linking Environment and Farming (LEAF) demonstrates, other forms of evidence that would be gathered during an on-site visit might still be required: "The preferred format of a remote audit is a video call supplemented by the business providing documentary evidence. Any technology that can include at least 3 parties can be used in order to enable remote witnessing of audits -for example, WhatsApp Call, BlueJeans, Microsoft Teams, Skype, Zoom. If this is not possible, the audit can involve a phone call supplemented by the business providing documentary and photo/video evidence" (LEAF Marque Remote Audit Protocol).
One other key concern in the shift to remote auditing raised by several VSS was data security. A strong illustrative example is provided by ASC, which developed a set of data security rules ( Table 2). For example, auditors must only record the data they require to complete the audit process and they must take special care in data storage. These rules were accompanied by an understanding that "the technology and tools shall allow auditors to confirm interviewee identity", as well as that those being interviewed "may not record the interview themselves" (ASC Policy for Audits During the COVID-19 Outbreak). Only record data with explicit consent of the interviewees. Afterwards the interviewees will verify and sign a checklist provided by the auditor containing at least the medium, date of recording, a short description and duration of storage of all that was recorded as part of the audit 6.3.3 Record only the data needed for the audit process.

6.3.4
Collect and store all data using up-to-date security practices. These measures include access control to the data collected and encrypted transmission of data, for instance when uploading and/or emailing.

6.3.5
Not store data beyond a required timeframe. The CAB shall specify how long each recorded file will be kept on the CAB's servers.

6.3.6
When the CAB and/or implementation of the certificate holder/ applicant are in doubt over these guidelines, the General Data Protection Regulation as released by the EU (May 25, 2018, https://gdpr-info.eu/) shall be referenced.

Policies Issued by VSS during the Pandemic
Nine VSS developed new policies during the early stages of the COVID-19 crisis. A complete summary of the new publicly-available policies developed in response to the pandemic is provided in Table 3. In all cases, the new policies were framed as interim policies, derogations, or exceptions, which was frequently indicated in the title of the new policy. "We are considering requests for desktop auditing and postponement of audits. All requests must be discussed with your certification bodies and they will contact Bonsucro. For Bonsucro members and potential members due to be audited after June 2020, we expect audits to be carried out as normal, however, we will continuously monitor the situation and act accordingly." These statements suggest that VSS expect that the remote practices are temporal. The decision to temporarily suspend audits only makes sense if there is an expectation that the regular auditing protocols will soon resume, while all of the decisions to permit remote auditing were accompanied with a specific end date or implication that they were permitted only during the pandemic. No VSS provided any indication that the new allowances made for remote auditing would be extended following the resumption of "business as usual." The focus of the interim policies, derogations, and exceptions were broadly consistent. The primary emphasis was on recognizing the need for flexibility in audit delays and the use of remote audits, all principally the result of travel-restrictions and the impossibility of conducting on-site audits.
Given the different areas of focus of the individual VSS, some of the amendments were also specific to the industry the standard covers. For example, the MSC provided guidance specific to the fisheries industry on chain of custody, while the Rainforest Alliance developed a policy focused on supply shortages arising from the pandemic specific to agricultural crops.
On balance, the VSS demonstrated a recognition of the extraordinary circumstances caused by the COVID-19 pandemic, but their initial responses have focused on the crisis at hand, rather than the longer-term implications that might arise from the crisis. These longer-term implications could include, for example, a greater openness to remote auditing even under "normal" business conditions. Beyond that issue, it is clear that the governance of the VSS was impacted by the COVID-19 policies, as many long-held practices were quickly modified and typical processes for standards development and modification were temporarily suspended. It is unclear from the publicly-available information if the VSS were concerned about whether these changes might hamper the credibility of their systems over the long-term, though it is important to note such concerns might be merited given the relative lack of stakeholder consultation in making the changes. These concerns must be balanced by the need to react quickly to an emerging crisis. It is fair to note that several VSS considered existing IAF requirements on force majeure and ICT when making their temporary amendments, and the credibility of VSS also rests, at least in part, and their ability to quickly react to crises so that their requirements reflect the realities faced by organizations and their auditors.

Discussion on Adoption of Technologies for Auditing
The results show that VSS were active in responding to the early stage of the COVID-19 crisis. Many VSS took unprecedented steps in rapidly modifying their governance regimes; foremost amongst those steps was a broad acceptance of remote auditing. That acceptance of remote auditing was, however, not universal, nor was it accepted for all types of audits.
Nine of the 21 VSS studied chose not to modify their existing auditing protocols to accommodate remote auditing options. It is possible that it will change if the COVID-19 crisis persists into mid-2020 or longer, but there is no indication that is the case at the time of this writing. Even in cases where remote auditing was permitted, that typically came with conditions. The use of remote auditing was typically limited to surveillance audits, an option provided by 11 VSS. Only one VSS was prepared to consider the possibility of a remote audit for an initial certification, and that came with a number of caveats. In the case of recertification audits, the solution was rather to extend the certificate until such time it was expected it would be possible to complete an on-site audit. Remote auditing was permitted with a number of requirements that were typically imposed, such as documenting changes to the audit protocol, ensuring that auditor competence could be established, and increasing provisions for data security. These requirements show that remote auditing is subject to strict oversight even in times of crisis.
All VSS expected that the modifications to their assurance systems would be temporary. All VSS either provided explicit time periods during which a remote audit would be acceptable or otherwise indicated that they expected normal auditing protocols to resume after the COVID-19 crisis. It is currently unclear when normal auditing protocols will resume across the world, and it is similarly unclear whether remote auditing will become a more established practice under normal conditions or whether it will remain as optional as part of crisis management of VSS.

Long-Term Implications for Remote Auditing
The shift to remote auditing during the pandemic also raises several long-term questions concerning remote auditing. For example, even during the early stages of the crisis, Fischer (2020) had already recognized that the experience with remote auditing could either exacerbate existing concerns or drive even more wide-reaching and lasting change in the auditing of VSS [12]: "So, does remote auditing sound too good to be true? Perhaps, but let's clarify what it means here. If remote means "trying to do the same thing from far away" -the truthfulness of the audit will inevitably drop overtime. It simply means that auditors won't even be able to smell that the paint is fresh. In other words, they would get less 'hints' if what they see is real and representative of a well performing company -or just a 'cover up', as this is what good auditors do. They would even be further confined in choosing where to look and what to audit. Under this scenario, after COVID-19, the auditing sector would likely move back to "traditional auditing", no matter what its well-known limitations are. By contrast, if remote means real time direct access to information (the way the term is used in IT and telecommunications), the COVID-19 crisis may create the innovations boost that the rather conservative audit sector has been in need of." There are several implications of the experience with remote auditing obtained during the COVID-19 crisis. First, it will be interesting to see whether the openness to using remote auditing during the crisis will mean that VSS are more open to using it in the future during "business as usual" conditions. This could depend, at least in part, on perceptions of the use of remote auditing during the crisis, particularly whether it is perceived to be as effective as on-site auditing. There are trade-offs in using remote auditing; although it means clients and their auditors do not need to incur the time and expense of an on-site visit, it can also be difficult or impossible to pick up cues that can inform important audit conclusions, such as body language, smells, noise, unplanned interactions, and interpersonal behavior. Prior to the COVID-19 crisis, VSS had demonstrated a clear preference for on-site audits for these, and other, reasons and it is not yet clear if the use of remote auditing during the pandemic will in any way alter those preferences. The future use of remote auditing could also depend on whether VSS are subjected to new pressures from their users and/or other stakeholders to show greater flexibility in the form of audits. These implications lead to several potential questions for future research, such as:

•
Has the experience with remote auditing during the COVID-19 crisis changed VSS' views on its applicability to their certification processes? • To what extent do VSS users and other stakeholders prefer on-site auditing to remote auditing (or vice versa)?
Second, if there is a greater openness to using remote auditing in VSS in the future, it will be important to establish the conditions under which it does and does not make sense. For example, there may be cases where it is too risky to rely exclusively on remote auditing. Would VSS, and customers relying on the signal certification to that VSS provides, be comfortable with using remote auditing to ensure conformance on issues related to food safety? Moreover, as discussed in the Background section, VSS certification is intended to provide a signal of a process, system, or product attribute [28][29][30]. If there are any concerns with, for example, the credibility of remote audits, these could undermine the credibility of the VSS certification and, over time, erode the strength of the signal that certification provides [4]. Moreover, any weakening of the signal provided by the certification could further exacerbate concerns about information asymmetry arising from a widening gap in knowledge about the certified process, system, or product between the parties making decisions based, at least in part, on that signal [29,34]. Even in cases where remote audits are deemed to not compromise safety, the question of whether they should be used for all types of audits (e.g., initial, surveillance, re-certification) will remain. This highlights that, even in cases where remote auditing is permitted, it might be restricted to certain uses. Based on the discussion above, example questions for future research could include:

•
Under what conditions is remote auditing appropriate? To what extent does the use of remote auditing change stakeholder views on credibility of the certification?
Third, it is unclear how a shift to remote auditing could impact the input and output legitimacy of VSS [34,35], another key contributor to the credibility of VSS that was discussed in the Background section. From an input legitimacy perspective, it is notable that the evidence gathered did not indicate that VSS undertook much, if any, stakeholder consultation regarding the shift to remote auditing during the COVID-19 crisis. It is possible that informal consultations with VSS' multi-stakeholder constituencies did occur in some cases, but these were not reported in the publicly-available data. Moreover, although the need to rapidly respond was understandable and necessary, the modifications were a departure from established norms for change within VSS, which emphasize thorough consultation. Consultation with VSS stakeholders, such as representatives from industry, non-governmental organizations, consumer groups, and government, is often one of the foundations of a VSS' credibility and is a precursor to procedural fairness, a consensual orientation, and transparency [64]. It will be interesting to see if the responses to the crisis have any lasting impact on the input legitimacy of the VSS or if there is a need to establish new protocols for consultation or where it might be suspended in response to future crises. In terms of output legitimacy, it will be interesting to observe the potential impact of remote auditing on views of rule enforcement and performance monitoring. For example, it will be interesting to explore whether a shift to remote auditing had any positive or negative effect on perceived audit inconsistencies, which was noted in the Background section as another key concern with respect to credibility [65]. Any concerns regarding reduced rule enforcement or lowered vigilance in performance monitoring could adversely impact the output legitimacy of VSS. These issues lead to questions such as, under what conditions are VSS and certified firms prepared to recognize that the quality of a remote audit is equivalent to, or possibly even better, than that of an on-site audit?
There are potentially other long-term ramifications of the rapid shift to remote auditing during the pandemic. Consider that some of the assurance practices that were relaxed during the crisis can potentially affect the integrity of certification services, especially if the crisis continues beyond six months (as was expected during the writing of this paper). For instance, as some VSS acknowledged, a reduction of unannounced audits was considered acceptable during the pandemic; moreover, little evidence was publicly available about witness/shadow assessments by of assurance bodies. It is worth considering whether remote auditing has weakened the governance regimes of VSS over both the short-and long-term. In any case, more development is needed to embed remote auditing as a regular practice within the certification services eco-system. With the above in mind, example questions to guide future research could include:

•
To what extent will the changes made during the pandemic impact stakeholder views of the procedural fairness, consensual orientation, and transparency of the VSS? • To what extent did the use of remote auditing change stakeholder views of rule enforcement and performance monitoring in VSS?

•
To what extent has the COVID-19 crisis caused VSS to re-evaluate their requirements?

Long-Term Implications for Technology-Enhanced Auditing
Notwithstanding the potential concerns raised above, there is the question of whether the experience gained with remote auditing during the crisis will create the opportunity and/or demand for increased use of technologies in auditing. In other words, it is as yet unclear whether this experience will open the door to increased use of technology-enhanced auditing (TEA). Apart from the question of demand, there is also the question of integrity of the current on-site auditing approach that is perceived as lacking veracity and timeliness [11,12,14]. As Gale et al., (2017) assert in the following quote: "With forest management, the audit is very much focused on management systems and processes. . . . The actual data collection of outcome and output is very limited, and whatever the forest manager says, as long as it looks reasonable, it's taken as agreed. You know, you are trying to audit 100,000 hectares in a week. The reality of you seeing anything on site is very, very limited. So you're very much reliant on the forest manager producing a map, or you produce a map, and the forest manager says, "This is what we've harvested. This is what we've restocked. Here are some timber figures." And that's pretty much trusted-99.9 percent of the time that's taken as correct." Therefore, the shift to TEA is also driven by the increased expectations in terms of input and output legitimacy of VSS. Technologies provide a different approach to create transparency and credibility [14]. Modern technologies can be used, for instance, for spot check audits of labelled products [50]. An existing example is provided by MSC, which conducts biannual DNA tests on a random sample of labelled products to confirm their origin [66]. DNA testing is also picking up in forestry to address illegal logging [67]. Drones or satellite imagining can be used to monitor remote areas or areas that are difficult to audit (as per the earlier example from forestry auditing) or that pose a health and safety risk [10]. Adoption of these practices thus has apparent benefits not only for the credibility of VSS, but also enhances emergency preparedness of VSS in times of crisis like the COVID-19 pandemic, as most of these technologies can be managed remotely. Further work is needed to embed these practices into current auditing practices.
However, the transition to TEA is challenging. An illustration of the key characteristics of TEA, compared to other forms of auditing, is provided in Table 4. In terms of approach, the key difference between TEA and other forms of auditing is in the role of technology: in TEA, technologies are a part of an auditor's decision making [52]. For instance, an auditor might use Big Data, text mining and AI as analytical and decision-making tools in TEA [68]; by contrast, in remote auditing, technologies make off-site auditing possible but do not play a role in the analysis. Another major difference between remote auditing and more advanced TEA is in challenges associated with data management: electronic data exchange (EDI) requires VSS to address data security and privacy; this is especially challenging in TEA where data can be exchanged amongst multiple parties. Furthermore, whilst remote audits (or assisted remote audits) rely primarily on ICT, TEA employs various technologies that are interlinked. The reliance on technologies is high in a TEA environment. Lastly, the competence of auditors differs significantly as well. Current rules for auditor's competence are well-established and during the crisis, VSS used this competence in remote auditing without much difference. However, in TEA, the auditor's competence differs significantly as auditors are seen as primarily analysts and must be comfortable working with a greater volume of data generated at speeds not possible in other forms of auditing [11]. As Castka et al. (2020) previously argued, research is needed to determine the impact of TEA on auditors' skills.
The potential adoption of TEA thus presents a substantial shift for VSS. Consider, for example, that VSS often operate globally and the capacity to implement TEA can vary widely. This could include issues as basic as poor internet connections in some areas, but could also include challenges such as a lack of access to capital to invest in TEA or an inability to recruit local experts to support the implementation and maintenance of the needed technologies. The fundamental point is that TEA requires a high level of technical sophistication, which could introduce challenges for both VSS and their clients. Closer collaboration between VSS stakeholders may be needed to broadly adopt TEA. Moreover, if VSS move towards greater acceptance of TEA, they may need to change aspects of their governance regimes and possibly may even need to rethink the requirements of their standards. The need to reconsider auditor competence has already been mentioned, but other issues could include considering whether existing stakeholder consultation approaches remain valid, audit frequencies should be changed, or product and process performance expectations should be modified, among other possibilities. VSS would need to make these decisions in light of potential concerns regarding the input and output legitimacy of their standards. There are many research possibilities for TEA, and many of those have been identified in a recent paper by Castka et al. (2020) [11]. Potential questions arising from the COVID-19 pandemic could include:

•
To what extent has the use of remote auditing during the COVID-19 pandemic changed stakeholder perspectives on the possibility of adopting technology-enhanced auditing? • What has the COVID-19 crisis revealed with respect to potential changes in requirements for auditor competence for remote and technology-enhanced auditing? • How does technology-enhanced auditing facilitate emergency preparedness? Note: 1 Assisted Remote Audit definition by ASC: "An audit that is conducted partly remotely and partly on-site. It typically occurs when at least one auditor (not technical expert or interpreter) of the audit team is able to be on site while the rest of the team are not due to the travel restrictions. The remote auditor shall coordinate and guide the collection of evidence with the auditor on-site".

Contributions of the Paper
The key contribution of the paper is in exploring the adoption of remote audits in VSS in the empirical setting of the emerging COVID-19 crisis. The data were collected during the relatively early stages of the crisis and responses may evolve over time, but the analysis showed a range of VSS views on adopting technologies for auditing. The analysis provided the basis for identifying numerous potential research questions on the future of remote auditing and, more broadly, technology-enhanced auditing in VSS. It also raises a number of implications for the VSS themselves, particularly with respect to the increased use of technology in their certification services and what that might mean for the long-term credibility of their efficacy, coverage, and enforcement and monitoring.
The paper contributes to the growing body of literature on VSS, specifically to veracity and timeliness of auditing and to governance of VSS, which are particularly understudied areas of VSS in the literature [7,47]. The paper provides an understanding of the uptake of technologies that can address the problems of inconsistent audits [65,69,70] and discusses the constraints in adopting these practices. It therefore adds to important theoretical perspectives that are employed in the context of VSS -such as signaling theory, institutional theory (symbolic and substantive adoption), or diffusion of innovation theory [71]. Among all these theoretical perspectives, the paper contributes by providing contextual understanding of the role of IT as an intervening variable to enhance signaling, reducing symbolic adoption, and enabling diffusion of organizational practices. The previous literature has often stated the need to address the veracity and timeliness of auditing practices, but most often this is framed from a conceptual perspective [11,13] rather than providing empirical evidence-with a few notable exceptions [14,50]. The paper also contributes to the organizational resilience literature [72,73] by providing an account of the role of IT as part of a response to an on-going crisis. In particular, it demonstrates the importance of industry preparedness in managing exogenous crises. VSS responses have shown that industry guidelines (in the context of this paper, the guidelines by IAF [8,74]) contributed to a consistent response of the VSS that chose to adopt remote auditing.

Limitations
At the time of this writing, COVID-19 is in its early stages and is still developing. It is possible that VSS responses to the crisis will continue to evolve. The policies and actions reported in this study, for example, are subject to ongoing review and revision in response to rapidly changing circumstances and the impact of the pandemic on operating environments around the world. This study presents a snapshot of VSS responses during the initial phases of the COVID-19 crisis (up to April 30, 2020) and is instructive in showing how VSS reacted to a crisis that threatened the foundation of the effectiveness of their assurance model, but the complete story has yet to be written.
The study also relies on publicly-available sources. Although most VSS included in this study were proactive in communicating through their websites, it is possible they took other actions that were not publicly-reported. For example, it was not possible to access any private communications VSS may have sent directly to their clients and stakeholders. This could have included some form of consultation with their stakeholders on the temporary modifications they made in response to the COVID-19 crisis. It is also acknowledged that the focus of this study was restricted to the actions VSS took with respect to remote auditing. Many VSS responded to the pandemic in other ways, such as recognizing the implications of potential supply shortages (e.g., Rainforest Alliance), acknowledging the potential social impacts arising from the crisis (e.g., FT International), and recognizing other actions taken by companies certified to their standards, such as product donations (e.g., Bonsucro). Finally, it was rarely possible to determine what types of technologies were used to complete remote auditing. Cases have been shared where that information was available, but further work will be needed to determine how technology was used to support the maintenance of certification services in different VSS. This could further inform ideas regarding the potential long-term implications for remote auditing and technology-enhanced auditing (TEA). Moreover, the lack of information on the use of specific technologies limits the conclusions that may be drawn regarding the future of TEA. Thinking on this issue has therefore been framed in the form of research questions, rather than propositions. Additional details on TEA are available elsewhere, particularly a report produced for ISEAL by Herding and Fischer (2015), and VSS have invested quite considerably into their capabilities alongside the ISEAL innovations fund workstream [15]. The report addresses the recent level of adoption of technologies in the context of VSS, as well as the technical and competence challenges related to adoption of TEA [54]. Castka et al. (2020) provide a comprehensive research agenda for TEA, which was developed prior to the pandemic [11]. The suggestions provided in this study may be viewed as complements, rather than replacements, for the research agendas proposed in earlier work.

Conclusions
The paper provides an early insight into the COVID-19 crisis that rapidly developed during the early months of 2020. The impact of the crisis on human lives and economic well-being has been significant and often tragic. In the context of VSS, for example, early reports suggest devastating consequences on farmers. FT International estimates that the price of cocoa will continue to drop, which will affect the entire sector. FT International also reports widespread job losses in the flower industry throughout the developing. The focus in this paper has been on the implications for remote auditing of VSS requirements, but it is important to remember the much bigger context in which the rapid transition to remote auditing occurred.
Despite the overwhelming challenges COVID-19 has created, people and organizations across the globe have demonstrated that they can take collective action to address aspects of the situation, rapidly implement previously inconceivable change (e.g., social distancing and remote work), and, hopefully, learn from the crisis and re-evaluate what is most important. At the time of the writing of this paper, VSS were still heavily impacted by world-wide lockdowns, but it is important to stress that they have worked hard to maintain their certification services during this difficult period. This paper has provided evidence of the efforts implemented by VSS during the early stages of the pandemic. It is hoped that this work will serve not only an as account of the early actions taken to address the crisis but also as an inspiration for further adoption of technologies for remote auditing and technology-enhanced auditing in VSS. Under the right conditions, increased adoption of TEA will ensure more efficient and effective processes of certification services-and hand in hand with these improvements-increased credibility and trustworthiness that consumers have in sustainable products.
Author Contributions: Conceptualization, all authors; methodology and analysis P.C. and C.S., writing by all authors. All authors have read and agree to the published version of the manuscript.
Funding: This research received no external funding. Acknowledgments: P.C. is grateful for administrative and technical support provided by Xiaoli Zhao.
Conflicts of Interest: P.C. and C.S. declare no conflict of interest. S.F. declares a conflict of interest with several mentioned standards. However, S.F. was not involved in the analysis to avoid COI. S.F.'s involvement and expertise was essential in the conceptualization of the study. AWS is a global multi-stakeholder initiative whose mission is to lead a global network that promotes responsible use of freshwater that is socially and economically beneficial and environmentally sustainable. AWS achieves this through a global water stewardship system, centred on the International Water Stewardship Standard, that drives, recognises and rewards good water stewardship performance.

Aquaculture Stewardship Council (ASC)
ASC is an independent, international non-profit organisation that manages the world's leading certification and labelling programme for responsible aquaculture. ASC recognises and rewards responsible aquaculture through the ASC aquaculture certification programme and seafood label; promotes best environmental and social choice when buying seafood; and contributes to transforming seafood markets towards sustainability.
https://www.asc-aqua.org/ The Better Cotton Initiative (BCI) BCI exists to make global cotton production better for the people who produce it, better for the environment it grows in and better for the sector's future. BCI aims to transform cotton production worldwide by developing Better Cotton as a sustainable mainstream commodity.
BCI works across the cotton supply chain to promote measurable and continuing improvements. https://bettercotton.org/

VSS Description (as Provided by ISEAL Website) Website
Bonsucro Bonsucro is a not-for-profit initiative dedicated to reducing the environmental and social impacts of sugar cane production. The Bonsucro Standard defines a set of globally applicable principles, criteria and indicators for sugar cane production. It aims to reduce the impact of sugar cane production on the environment in measurable ways and contribute to social and economic benefits for all concerned with the sugar supply chain. The Forest Stewardship Council International Center is an international not-for-profit organisation established to promote the responsible management of the world's forests.
FSC is a certification system that provides internationally recognised standard-setting, trademark assurance and accreditation to companies, organisations, and communities interested in responsible forestry. https://fsc.org/en

GEO Foundation
The GEO Foundation is a global non-profit organisation whose main activity areas include advocacy for sustainability in and through golf, guidance and standard setting, capacity building and certification. Working in close collaboration with the industry and wider stakeholders, the GEO Foundation addresses a gap in the market where cross cutting social and environmental issues for golf are addressed in a systematic way.
https://sustainable.golf/ Global Coffee Platform (GCP) The Global Coffee Platform is a membership organisation of coffee farmers, trade and industry and civil society. Members work jointly towards improving economic, social and environmental conditions for all who make a living in the coffee sector. The Global Coffee Platform is founded on a voluntary Code of Conduct comprising basic social, environmental and economic practices in coffee production, processing and trading.

VSS Description (as Provided by ISEAL Website) Website
GoodWeave GoodWeave is a non-profit organisation that seeks to end exploitative child labour in the carpet industry and offer educational opportunities to children and support to communities affected by exploitative practices by certifying carpets and rugs free from exploitive production. To earn the GoodWeave label, rug exporters and importers must be licensed under the GoodWeave certification programme.
https://goodweave.org/ Linking Environment and Farming (LEAF) LEAF is a registered charity based in the UK which promotes sustainable food and farming and aims to 'inspire and enable prosperous farming that enriches the environment and engages local communities'. It designs and operates the LEAF Marque Standard-a global environmental assurance system recognising sustainably farmed products, which focuses on core economic, environmental and social requirements. https://leafuk.org/

Marine Stewardship Council (MSC)
MSC is a certification and eco-labelling program for sustainable seafood from wild fisheries. The council works with fisheries, seafood companies, scientists, conservation groups and the public to promote the best environmental choice in seafood globally. MSC's standards cover sustainable fishing and seafood traceability. They ensure that MSC-labelled seafood comes from, and can be traced back to, sustainable fisheries. https://www.msc.org/home

Rainforest Alliance
The Rainforest Alliance is an international nonprofit organization working to build a future in which nature is protected and biodiversity flourishes, where farmers, workers, and communities prosper, and where sustainable land use and responsible business practices are the norm. We envision a world where people and nature thrive in harmony. In January 2018, the Rainforest Alliance merged with UTZ, a global program and label for sustainable farming. Our head offices are in Amsterdam and New York, with regional offices around the world. https://www.rainforest-alliance.org/

Responsible Jewellery Council (RJC)
The Responsible Jewellery Council is a not-for-profit, standards setting and certification organisation. It has more than 1,000 Member companies that span the jewellery supply chain from mine to retail. RJC Members commit to and are independently audited against the RJC Code of Practices-an international standard on responsible business practices for diamonds, gold and platinum group metals.

Roundtable on Sustainable Biomaterials (RSB)
The mission of RSB is to ensure that the use of biomass and derived bio-products, including biofuels, delivers on their promises of climate change mitigation, economic development and energy security without causing environmental or social damage. The standard developed by the RSB consists of a set of normative documents and guidelines. It covers the entire biofuel value chain from "farm to tank". https://rsb.org/

VSS Description (as Provided by ISEAL Website) Website
Roundtable on Sustainable Palm Oil (RSPO) RSPO is a non-profit association that unites stakeholders to develop and implement global standards for sustainable palm oil. The RSPO has developed a set of environmental and social criteria which companies must comply with in order to produce Certified Sustainable Palm Oil (CSPO) and help to minimise the negative impact of palm oil cultivation on the environment and communities in palm oil-producing regions.
https://rspo.org/ Sustainable Agriculture Network (SAN) SAN is an international network of NGOs focused on helping companies, producers and donors to move forward with their sustainability agenda in a practical and efficient way. SAN provides innovative, practical and credible agricultural solutions to some of the most pressing environmental and social problems of our time.
https: //www.sustainableagriculture.eco/ Textile Exchange Textile Exchange is a global non-profit that works closely with our members to drive industry transformation in preferred fibers, integrity and standards and responsible supply networks. We identify and share best practices regarding farming, materials, processing, traceability and product end-of-life in order to reduce the textile industry's impact on the world's water, soil and air, and the human population.
https://textileexchange.org/ Union for Ethical BioTrade (UETB) UEBT is a non-profit association that promotes the sourcing of natural ingredients with respect for people and biodiversity. UEBT advances practices for biodiversity innovation and sourcing that promote sustainable business growth, local development and conservation. UEBT promotes Ethical BioTrade by offering members independent verification, technical support and networking opportunities.
https://www.ethicalbiotrade.org/ UTZ UTZ is a global program and label for sustainable farming. In January 2018, we merged with the Rainforest Alliance, an international nonprofit organization and certification program, taking the Rainforest Alliance name. Together, we are working to build a future in which nature is protected and biodiversity flourishes, where farmers, workers, and communities prosper, and where sustainable land use and responsible business practices are the norm. We envision a world where people and nature thrive in harmony. Our head offices are in Amsterdam and New York, with regional offices around the world. https://utz.org/