Table 1:

Abstract filtering rules. Items were retained if any of rules 1-3 applied, and filtered out otherwise.

Rule Number	Source of Publication Type or Study Design Information	Taggers and MeSH terms relevant to study designs over the 10 reviews	Condition
Rule 1	Multi-Tagger	Case-Control Studies Clinical Study Cohort Studies Meta-analysis Practice Guideline Prospective Studies Randomized Controlled Trial Retrospective Studies Systematic Review	Above threshold that gave the optimal F18; or item not processed by Multi-Tagger (i.e., article not in English or lacking abstract)
Rule 2	Web RCT Tagger	Randomized Controlled Trial	Above 0.01 threshold for RCTs9; or item not processed by Web RCT Tagger (i.e., article not in English or lacking abstract)
Rule 3	MeSH Terms and Publication Types	Case-Control Studies Clinical Study Clinical Trial Cohort Studies Meta-Analysis Observational Study Practice Guideline Prospective Studies Randomized Controlled Trial Retrospective Studies Systematic Review	One or more relevant study design terms were applied in NLM MeSH indexing.