Table 3

Risk of bias assessment based on Downs and Black’s criteria16

AuthorYearReportingInternal validityConfounding and selection biasExternal validityPowerTotal score
Banerjee et al*9202018
Campbell et al23201612
Chigbu et al*18202017
Duan et al*28202121
Eakin et al24201817
Fokom Domgue et al25202014
Joshi et al26201520
Joshi et al*10201317
Mungo et al*19202019
Naud et al*22201614
Pinder et al*11202024
Sandoval et al*20201920
Viviano et al*21201721
Zhao et al*12202119
Zhao et al27202020
  • Subsections were scored green if over 80% of indicators met, orange if 40%–79% of indicators met and red if <40% of indicators met.

  • *Included in the meta-synthesis.