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Table 2 The results of search databases, risk of bias assessment, and data extraction for SR/MA

From: Methodological steps used by authors of systematic reviews and meta-analyses of clinical trials: a cross-sectional study

VariableNumber (%)
Number of databases used in SR/MA, n = 382
 1–244 (11.5)
 3–5241 (63.1)
 6–1075 (19.6)
  > 1022 (5.8)
Searched Grey Literature Databases, n = 378186 (49.2)
Conduct a manual search, n = 380
 Always171 (45.0)
 Often92 (24.2)
 Sometimes64 (16.8)
 Seldom35 (9.2)
 Never18 (4.7)
While extracting the data, you accidentally found a new relevant paper. Did you include this paper via manual search or other sources? n = 371
 Yes351 (94.6)
 No20 (5.4)
Did you update the search to get more recent papers, n = 370
 Yes323 (87.3)
 No47 (12.7)
Tools used to evaluate the risk of bias of clinical trials, n = 351
 Cochrane Collaboration’s tool263 (74.9)
 Other (Downs & Black, CONSORT, MODIFIED JADAD, CAMARADES TOOL, Pedro, GRADE….)88 (25.1)
Number of reviewers in a team to extract the data, n = 384
 One reviewer extracts it, another or more reviewers check it116 (30.2)
 Two reviewers extract it223 (58.1)
 Three reviewers extract it20 (5.2)
 Four or more reviewers extract it25 (6.5)
The original articles give the data in only figures or graphical representation, n = 376
 Contact authors to get raw data211 (56.1)
 I did not know there is a digital software to extract it75 (19.9)
 Use a digital software to extract it77 (20.5)
 I did not extract it because I think the digital software is unreliable13 (3.5)
The data used in extracting the survival percentage. n = 356
 Raw data118 (33.1)
 Percentage estimated from Kaplan-Meier curve50 (14.0)
 I have never analyzed it177 (49.7)
 Other11 (3.1)
  1. The data is represented by the number and percentage (%). SR/MA: systematic review and meta-analysis
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