Table 3

Application of the procedures to counter-balance some common research malpractices

ALLAnswerNo answerp Value
NPer centNPer centNPer cent
Number of systematic reviews11810080683832
Search of unpublished trials and/or test for publication bias0.914
 Publication bias discussed only or not mentioned393326331334
 Unpublished trials searched OR publication bias tested564739491745
 Unpublished trials searched AND publication bias tested23191519821
Contact with authors of the studies0.427
 Study authors not contacted453828351745
 Study authors contacted for method or unspecified reason1513121538
 Study authors contacted for unreported outcomes584940501847
Duplicate publications0.057
 Not searched or not mentioned373121261642
 Searched and found, not referenced OR no mention of results716054681745
 Searched, found and referenced10856513
Sponsors of the studies0.809
 Not mentioned917763792874
 Information extracted21181316821
 Information extracted and subgroup analyses performed654525
Conflicts of interests of study authors0.703
 Not mentioned1139677963695
 Information extracted543425
 Information extracted and subgroup analyses performed000000
Ethical approval of included studies0.481
 Not mentioned11597779638100
 Information extracted333400
 Information extracted and subgroup analyses performed000000
Number of procedures applied0.403
  1 or 2 procedures484134431437
  3 or 4 procedures564738481847
  5 procedures332313
 Median (IQR)2.5 (1–3)2.5 (2–3)2.5 (1–3)
Explicit mention of misconduct by reviewers0.296
 No, or not mentioned1119474933797
  • Answer: reviews in which extracted data were confirmed by reviewers. No answer: reviews in which extracted data were not confirmed by reviewers. p Value testing the null hypothesis of equal distribution between the reviews for which the authors responded to our inquiry and those who did not (χ2 test). Percentages may not add-up to 100% because of rounding errors.