Purpose: Retail Sales Indices measure sales of retail enterprises of different types and sizes on a monthly basis. Furthermore, it is aimed to follow the development in monthly and yearly basis, to have data consistent with the European Union regulations, to ensure the possibility of international comparisons on Retail Trade Sector.
In addition to measuring the development of Retail Trade sector the indices are also considered as indicators of consumer confidence and household demand. For this reason, it is accepted as one of the most important indicators to monitor the economic condition.
Retail Sales Indices are involved in European Principal Economic Indicators (PEEIs). The indices are also considered as an important economic indicator in other developed countries besides the EU.
Coverage: All the enterprises which give VAT declaration to the Revenue Administration are included in the index calculation.
Classifications: The indices are calculated according to the NACE Rev. 2 economic activity classification. The activities covered are as follows.
Computers, peripheral units and software, books, telecommunications equipment, etc.
Audio and video equipment, hardware, paints and glass, electrical household appliances, furniture, etc.
Geographical coverage: The whole country (Turkey) is covered.
Economic activity coverage: The index covers the “Division 47 - Retail Trade (Except Motor Vehicles and Motorcycles)” of NACE Rev.2 activity classification.
The activity groups covered according to the European Union Short Term Statistics regulations are as follows.
A- Reference period and periodicity: The reference period is the period until the last day of each month on the first day and the frequency of the survey is monthly.
Turnover (VAT excluded): Turnover comprises the total value of goods and services invoiced by enterprise in reference month and this corresponds to market sales of goods and services supplied to third parties. Turnover includes invoiced by unit vis-a-vis its customer (exception of VAT and deductible taxes linked to turnover) other all taxes and duties. Turnover also includes all other charges (transport, packaging, etc.) passed on to the customer, even if these charges are listed separately in the invoice.
Turnover does not include price decline, discount and allowance, recycling package. The income which is classified in the company’s account as other business income, financial income and extraordinary income are excluded in turnover. Business subventions obtained from the government are also excluded.
1- Index type: A simple index is used which is calculated by dividing the relevant levels by the base year averages.
Calculation of volume index: Indices measuring retail sales are produced with constant prices. Volume measurement is obtained by adjusting turnover data from price effects.
In calculation of Retail Sales Indices at current prices are deflated by price relatives. For this purpose, CPI results produced at "Classification of Individual Consumption According to Purpose (COICOP)" level are calculated according to NACE Rev.2 level. "Household Budget Survey" data is used for this transition.
As a result of deflating current price Turnover Index by price relatives at appropriate levels, Retail Sales Volume Index with constant prices is reached. Since the price indices used are compiled as VAT included, the Turnover Indices are also calculated in VAT included form before deflation process. Thus, the possible changes in the VAT rates do not affect the volume measure.
4- Impact and Contribution analysis: Impact and contribution analysis are done on enterprise basis by sectors.
Data sources: VAT declarations obtained from the Revenue Administration are used as the data source for the compiling of retail sale indices.
Aggregation: Retail Sales Indices are aggregated for food, drinks and tobacco; non-food (except automotive fuel); automotive fuel activities of NACE Rev.2 classification and for Retail Trade in general.
Data compilation: VAT declarations are compiled monthly from Revenue Administration.
The Revision Information Form regarding the revisions to be carried out in the current year for the statistics produced in the scope of this press release can be accessed from the link below.
The seasonal adjustment of Retail Sales Indices is carried out using TRAMO-SEATS methodology. The software that is used for the application of this method is JDemetra+ developed by the National Bank of Belgium (NBB) in cooperation with the Deutsche Bundesbank and Eurostat in accordance with the Guidelines of the European Statistical System.
Seasonal and calendar adjustment process of Retail Sales Indices begins at the end of each year with the identification of the models of next year. This specified model structure is kept fixed throughout the year to adjust seasonally and/or calendar effects. At the end of the year, just like the previous year, specification of econometric estimation models for the following year is done. The identified process repeats itself in a cyclical manner each year.
The indices are seasonally and calendar adjusted at retail trade in general, food, drinks and tobacco, non-food (except automotive fuel), computers, peripheral units and software, books, telecommunications equipment, etc., audio and video equipment, hardware, paints and glass, electrical household appliances, furniture, etc, non-food, retail trade (except automotive fuel), non-specialised shops and automotive fuel activities. While all subtitles of Retail Sales Indices contain both seasonal effects, 20 subtitles contain calendar effect.
The approach in seasonal and calendar adjustment for Retail Sales Indices is indirect. Namely, the individual subtitles of retail trade series are seasonally adjusted and then aggregated to derive seasonally and calendar adjusted totals. The advantages of the indirect approach are easy calculation of contributions to growth from components of main aggregates and retaining additivity.
Seasonal adjustment procedure is subject to revisions over time because of the re-estimation of seasonal component as new observations are added. These revisions are implemented on the data of the last three years excluding the current year.
Adjusted data has been published in 3 different ways.
“Calendar adjusted” data is derived from unadjusted data by removing calendar and holiday originated effects. Calendar adjusted data should be used in comparisons regarding the same month/period of the previous year.
“Seasonally adjusted” data is derived from unadjusted data by removing effects originating from seasonal effects. Seasonally adjusted data should be used in comparisons regarding the previous month/period.