Table 1 Stepwise approach for applying the reproducibility concept to systematic reviews

Step 1 (obligatory): replicate all searches in bibliographic databases and combine them in one database

Step 2 (obligatory; percentage can be increased, e.g. in case of review including a small number of studies): draw a 25% random sample

Step 3 (obligatory): perform study selection (title&abstract and full-text) in the same way as reported, and applying the same criteria as reported in the original SR

Step 4 (obligatory): extract data for the main outcomes (e.g. primary outcomes, outcomes shown in the main text only (i. e. excluding supplementary materials))

Step 5 (obligatory): assess risk of bias/methodological quality as in the original SR

Step 6 (optional^a): perform evidence synthesis as in the original SR. This might include meta-analyses (also including studies found to meet eligibility criteria not included in the original review) and applying systems for assessing the quality of evidence such as GRADE, for example