***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Although r and omised trials are important for evidence -based medicine , little is known about their overall characteristics . We assessed the epidemiology and reporting of method ological details for all 519 PubMed -indexed r and omised trials published in December , 2000 ( 383 [ 74 % ] parallel-group , 116 [ 22 % ] crossover ) . 482 ( 93 % ) were published in specialty journals . A median of 80 participants ( 10th-90th percentile 25 - 369 ) were recruited for parallel-group trials . 309 ( 60 % ) were blinded . Power calculation , primary outcomes , r and om sequence generation , allocation concealment , and h and ling of attrition were each adequately described in less than half of publications . The small sample sizes are worrying , and poor reporting of method ological characteristics will prevent reliable quality assessment of many published trials When reading a clinical research article , the clinician must judge if the reported findings and conclusions are valid before applying them to patient care . This concern is legitimate given the wide range of study validity in the clinical literature . In this article , the authors present many validity markers that signify the quality of the information reported from a study , such as authors hip , bias , confounding , statistics , r and omization , controls , blinding , and the logical framework of scientific investigations The statistical adequacy of all papers published in the period 1976 - 80 describing clinical trials of five non-steroidal anti-inflammatory and two analgesic drugs introduced into the UK market in 1978 and 1979 has been assessed using a checklist of simple criteria . Most trials were reported to be r and omised and double-blind . Trial design s were less satisfactory in other important respects ; the sample size of most trials was inadequate to demonstrate superiority of the new drug compared with an active control therapy . The period of treatment assessment was short in view of the likelihood of prolonged prescription of drugs in these classes . It is suggested that licensing authorities should dem and higher st and ards of clinical trial evidence offered in support of new drugs Recent empirical evidence supports the importance of adequate r and omization in controlled trials . Trials with inadequate allocation concealment have been associated with larger treatment effects compared with trials in which authors reported adequate allocation concealment . While that provides empirical evidence of bias being interjected into trials , trial investigators rarely document the sensitive details of subverting the intended purpose of r and omization . This article relates anonymous accounts run the gamut from simple to intricate operations , from transillumination of envelopes to search ing for code in the office files of the principal investigator . They indicate that deciphering is something more frequent than a rate occurrence . These accounts prompt some method ological recommendations to help prevent deciphering . R and omized controlled trials appear to annoy human nature -- if properly conducted , indeed they should In the r and omized , placebo-controlled , physician-blinded Canadian cooperative trial of cyclophosphamide and plasma exchange , neither active treatment regimens ( group I : IV cyclophosphamide and prednisone ; group II : weekly plasma exchange , oral cyclophosphamide , and prednisone ) were superior to placebo ( group III : sham plasma exchange and placebo medications ) using the blinded , evaluating neurologists ' assessment s of disease course ( primary analysis ) . All patients were examined by both a blinded and an unblinded neurologist at each assessment in this trial . We compared the blinded and unblinded neurologists ' judgment of treatment response and analyzed the clinical behavior of patients who correctly guessed their treatment . The unblinded ( but not the blinded ) neurologists ' scores demonstrated an apparent treatment benefit at 6 , 12 , and 24 months for the group II patients ( not group I or placebo ; p < 0.05 , two-tailed ) . There were no significant differences in the time to treatment failure or in the proportions of patients improved , stable , or worse between the group II and group III patients who correctly guessed their treatment assignments and those who did not . Physician blinding prevented an erroneous conclusion about treatment efficacy ( false positive , type 1 error ) A system has been constructed to evaluate the design , implementation , and analysis of  r and omized control trials ( RCT ) . The degree of quadruple blinding ( the r and omization process , the physicians and patients as to therapy , and the physicians as to ongoing results ) is considered to be the most important aspect of any trial . The analytic techniques are scored with the same emphasis as is placed on the control of bias in the planning and implementation of the studies . Description of the patient and treatment material s and the measurement of various controls of quality have less weight . An index of quality of a RCT is proposed with its pros and cons . If published papers were to approximate these principles , there would be a marked improvement in the quality of r and omized control trials . Finally , a reasonable st and ard design and conduct of trials will facilitate the interpretation of those with conflicting results and help in making valid combinations of undersized trials BACKGROUND The interpretation of the results of r and omized controlled trials ( RCTs ) has traditionally emphasized statistical significance rather than clinical importance . Our aim was to assess the quality of reporting of factors related to clinical importance in a sample of published RCTs . METHODS A r and om sample of 27 ( of a total of 266 ) RCTs published in 5 major medical journals over a 1-year period were review ed by 4 independent review ers for factors considered important in the interpretation of the clinical importance of study results : identification of a clearly defined primary outcome , reporting of the expected difference between groups used in the calculation of sample size ( the delta value ) and whether it was based on the minimal clinical ly important difference of the intervention , the statistical significance of the results , presentation of pertinent confidence intervals , and the authors ' interpretation of the clinical importance of the results . RESULTS Twenty-two of 27 ( 81 % ) articles explicitly reported a single primary outcome . Of the 20 articles that included a sample size calculation , 18 ( 90 % ) reported a delta value . Two of the 18 ( 11 % ) articles explicitly stated that the delta value was chosen to reflect the minimal clinical ly important difference of the intervention . For the primary outcomes , confidence intervals surrounding the point estimates of the efficacy of the interventions were reported in 11 of 27 ( 41 % ) studies . The study results were interpreted from the perspective of clinical importance in 20 of 27 ( 74 % ) of the articles . Of these 20 reports , 5 ( 25 % ) provided justification for their clinical interpretation of the results . INTERPRETATION Authors of RCTs published in major general medical and internal medicine journals do not consistently provide their own interpretation of the clinical importance of their results , and they often do not provide sufficient information to allow readers to make their own interpretation BACKGROUND Traditional and largely qualitative review s of evidence are now giving way to much more structured systematic overviews that use a quantitative method to calculate the overall effect of treatment . The latter approach is dependent on the quality of primary studies , which may introduce bias if they are of poor method ologic quality . OBJECTIVE To test the hypothesis that the inclusion of poor- quality trials in meta-analyses would bias the conclusions and produce incorrect estimates of treatment effect . METHODS An overview of r and omized trials of antiestrogen therapy in subfertile men with oligospermia was performed to test the hypothesis . Data sources included online search ing of MEDLINE and Science Citation Index data bases between 1966 and 1994 , scanning the bibliography of known primary studies and review articles , and contacting experts in the field . After independent , blind assessment , nine of 149 originally identified studies met the inclusion criteria and were selected . We assessed study quality independently . Outcome data from each study were pooled and statistically summarized . RESULTS There was a marginal improvement in pregnancy rate with antiestrogen treatment ( odds ratio , 1.6 ; 95 % confidence interval , 0.9 to 2.6 ) . Sensitivity analyses on the basis of method ologic quality demonstrated that poor- quality studies produced a positive effect with treatment , whereas no benefit was observed with high- quality studies . CONCLUSION The results of a meta- analysis are influenced by the quality of the primary studies included . Method ologically , poor studies tend to exaggerate the overall estimate of treatment effect and may lead to incorrect inferences Systematic Review Series Series Editors : Cynthia Mulrow , MD , MSc Deborah Cook , MD , MSc The last article in this series outlined methods with which to search the literature for studies on the clinical question that generates a systematic review [ 1 ] . Herein , we discuss the subsequent steps of selecting and appraising  studies  for a review . Both of these steps involve important judgments that can influence the results of a review . In selecting studies , review ers judge the relevance of the studies to the review question . In appraising studies , review ers judge numerous features of design and analysis . Some of these judgments are easy to make ; others are more difficult and prone to error . To be confident in their decisions , review ers should use methods that are reliable ( the results do not change if the procedure is repeated ) , impartial ( not influenced by the study results ) , and explicit ( unambiguous ) [ 2 ] . These strategies for selection and appraisal are sensible , and they distinguish most systematic review s from most narrative review s. However , evidence to support the importance of some of the methods we suggest is either scant or conflicting ; readers are referred to the original research on these approaches for more details . Selecting Studies for Systematic Review s If review ers perform a comprehensive search of the literature using the methods described previously in this series [ 1 ] , they will probably have assembled a large sample of articles . This sample will include most ( ideally , all ) studies that are relevant to the review question ( that is , the sensitivity of the search will be high ) . Inevitably , because such a wide net is cast , articles not pertinent to the clinical question will be retrieved ( that is , the specificity of the search will be modest ) . Thus , the review ers ' next task is to sort through all of the potentially relevant articles and select those that will be included in the review . To do so , review ers adopt several of the tactics listed in Table 1 and Table 2 for planning and executing the selection process ( in effect , improving the specificity of the search ) ; these tactics are described below . Table 1 . Planning Study Selection Table 2 . Strategies for Selecting and Appraising Studies Begin with a Well-Built Clinical Question Review ers should ensure that the question for review includes the four elements of a well-built clinical question [ 3 , 4 ] : the patients of interest , the main interventions under investigation , the comparison interventions , and the clinical outcomes of interest . By including these four elements , review ers can better focus the selection process . Choose Selection Criteria That Fit the Clinical Question Consider a systematic review of the effectiveness of a drug treatment ( for example , a proton-pump inhibitor ) for patients with a particular disorder ( such as esophageal reflux ) . Review ers need to decide whether to include studies of patients with any symptoms of reflux , only those with classic symptoms , or only those in whom definitive diagnostic tests have confirmed the presence of reflux . In addition , review ers might choose to include studies of patients with different comorbid conditions ; patients from different demographic or geographic or cultural background s ; or patients from different health systems , such as inpatient or community population s. Similarly , review ers should use selection criteria that reflect the main and comparison interventions of interest . In our esophageal reflux example , review ers would need to decide whether to include studies of a particular drug or studies of all agents in that drug 's class and whether to include studies of any dose and regimen or only studies with a specific regimen . For the comparison interventions , the review ers would decide whether to include studies that compare the experimental drug with alternate treatments ( such as antacids or histamine-2-receptor antagonists ) , with placebo , or with both . For the clinical outcomes , review ers have analogous tasks of defining the outcomes and translating them into criteria . In our example , the review ers would start by listing each clinical outcome ( for example , whether the outcome was endoscopic or clinical and whether it focused on cure or persistence ) and then decide whether to include studies that reported any outcome or only those with certain clinical ly important outcomes ( such as improvement in symptoms at 1 year ) . After thoroughly considering each element of the review question , review ers compile a set of explicit selection criteria . When these criteria are not explicit , the results of the review are more prone to error [ 5 , 6 ] . Reporting the selection criteria used in a review is extremely important to readers because the criteria indicate the relevance of the review to the readers ' clinical practice . Specify the Types of Study Design To Be Included After creating selection criteria that appropriately reflect the review question , review ers should consider which study design s to include . Ideally , review ers choose study design s that are most likely to produce valid results . For example , to answer questions about therapy or harm , review ers may want to include r and omized trials [ 7 ] because they provide more accurate estimates of benefit or harm than do cohort studies , casecontrol studies , and case series [ 8 ] . In reality , however , r and omized trials may not be conducted to address questions of harm [ 9 ] . Therefore , review ers need to consider which study design s are likely to be available to answer their question ; this information may necessitate modification of originally conceptualized selection criteria to incorporate observational ( nonexperimental ) studies . Specify Criteria Related to Type and Form of Publication Review ers also need to consider issues related to type and form of publication . Ideally , all of the relevant studies would be published as peer- review ed journal articles . However , some completed studies may be published only as abstract s , in non-peer- review ed form , or not at all . Review ers decide whether to include these incompletely reported studies when planning their literature search . By including all articles in various stages of publication and subjecting them to rigorous critical appraisal , review ers minimize the threat of publication bias ( the preferential reporting of studies with positive results ) [ 10 - 12 ] , which could generate misleading review s. Other studies may be reported more than once . To avoid over-representing duplicate studies in the review , investigators should plan to look for and exclude duplicate publications [ 13 ] . Finally , because studies may be published in different language s and because excluding studies published in different language s may bias the results of review s [ 14 , 15 ] , articles should be included , as appropriate 
    Output:
    
The field test of the new instrument showed good criterion validity .
Participants found it useful in translating evidence from RCTs to practice .
Conclusion A new instrument for the critical appraisal of RCTs of NPs was developed and tested .
The instrument is distinct from other available assessment instruments for RCTs of NPs in its systematic development and validation .