Skip to main content

Table 1 Number of risk of bias tools listed by study designs included

From: Risk of bias tools in systematic reviews of health interventions: an analysis of PROSPERO-registered protocols

Number of tools listedStudy designs to be included in systematic review
N (%)
RCT only
N = 175
RCT and NRS
N = 296
All protocols
N = 471
015 (8.6)31 (10.4)46 (9.8)
1156 (89.1)163 (55.1)319 (67.7)
24 (2.3)77 (26.0)81 (17.2)
3+0 (0.0)9 (3.0)9 (1.9)
Suite of tools*0 (0.0)16 (5.4)16 (3.4)
  1. NRS = non-randomized study, RCT = randomized controlled trial
  2. Included quasi-RCT
  3. Included non-randomized experimental designs, quasi-experimental studies, and observational studies
  4. *Suite of tools: the RoB tool was comprised of separate checklists for different study designs produced by the same organization, but the number of checklists to be used was not specified