Measuring test-retest reliability (TRR) of AMSTAR provides moderate to perfect agreement – a contribution to the discussion of the importance of TRR in relation to the psychometric properties of assessment tools

Background!#!Systematic Reviews (SRs) can build the groundwork for evidence-based health care decision-making. A sound methodological quality of SRs is crucial. AMSTAR (A Measurement Tool to Assess Systematic Reviews) is a widely used tool developed to assess the methodological quality of SRs of randomized controlled trials (RCTs). Research shows that AMSTAR seems to be valid and reliable in terms of interrater reliability (IRR), but the test retest reliability (TRR) of AMSTAR has never been investigated. In our study we investigated the TRR of AMSTAR to evaluate the importance of its measurement and contribute to the discussion of the measurement properties of AMSTAR and other quality assessment tools.!##!Methods!#!Seven raters at three institutions independently assessed the methodological quality of SRs in the field of occupational health with AMSTAR. Between the first and second ratings was a timespan of approximately two years. Answers were dichotomized, and we calculated the TRR of all raters and AMSTAR items using Gwet's AC1 coefficient. To investigate the impact of variation in the ratings over time, we obtained summary scores for each review.!##!Results!#!AMSTAR item 4 (Was the status of publication used as an inclusion criterion?) provided the lowest median TRR of 0.53 (moderate agreement). Perfect agreement of all reviewers was detected for AMSTAR-item 1 with a Gwet's AC1 of 1, which represented perfect agreement. The median TRR of the single raters varied between 0.69 (substantial agreement) and 0.89 (almost perfect agreement). Variation of two or more points in yes-scored AMSTAR items was observed in 65% (73/112) of all assessments.!##!Conclusions!#!The high variation between the first and second AMSTAR ratings suggests that consideration of the TRR is important when evaluating the psychometric properties of AMSTAR.. However, more evidence is needed to investigate this neglected issue of measurement properties. Our results may initiate discussion of the importance of considering the TRR of assessment tools. A further examination of the TRR of AMSTAR, as well as other recently established rating tools such as AMSTAR 2 and ROBIS (Risk Of Bias In Systematic reviews), would be useful

AMSTAR 2 is only partially applicable to systematic reviews of non-intervention studies : a meta-research study

Objectives: A measurement tool to assess systematic reviews 2 (AMSTAR 2) was originally developed for systematic reviews (SRs) of health-care interventions. The aim of this study was to assess the applicability of AMSTAR 2 to SRs of non-intervention studies. Study design and setting: This was a meta-research study. We used 20 SRs for each of the following four types of SRs: Diagnostic Test Accuracy reviews, Etiology and/or Risk reviews, Prevalence and/or Incidence reviews, and Prognostic reviews (80 in total). Three authors applied AMSTAR 2 independently to each included SRs. Then, the authors assessed the applicability of each item to that SR type and any SR type. Results: Researchers unanimously indicated that 7 of 16 AMSTAR 2 items were applicable for all four specific SR types and any SR type (items 2, 5, 6, 7, 10, 14 and 16), but 8 of 16 items for any SR type. These items could cover generic SR methods that do not depend on a specific SR type. Conclusion: AMSTAR 2 is only partially applicable for non-intervention SRs. There is a need to adapt/extend AMSTAR 2 for SRs of non-intervention studies. Our study can help to further define generic methodological aspects shared across SR types and methodological expectations for non-intervention SRs