Table 1. Criteria for assessing the risk of bias of studies included
Pre-Post study Design21
  1. Was the study question or objective clearly stated?
  2. Were eligibility/selection criteria for the study population prespecified and clearly described?
  3. Were the participants in the study representative of those who would be eligible for the test/service/intervention in the general or clinical population of interest?
  4. Were all eligible participants that met the prespecified entry criteria enrolled?
  5. Was the sample size sufficiently large to provide confidence in the findings?
  6. Was the test/service/intervention clearly described and delivered consistently across the study population?
  7. Were the outcome measures prespecified, clearly defined, valid, reliable, and assessed consistently across all study participants?
  8. Were the people assessing the outcomes blinded to the participants' exposures/interventions?
  9. Was the loss to follow-up after baseline 20% or less? Were those lost to follow-up accounted for in the analysis?
  10. Did the statistical methods examine changes in outcome measures from before to after the intervention? Were statistical tests done that provided p values for the pre-to-post changes?
  11. Were outcome measures of interest taken multiple times before the intervention and multiple times after the intervention (i.e., did they use an interrupted time-series design)?
  12. If the intervention was conducted at a group level (e.g., a whole hospital, a community, etc.) did the statistical analysis take into account the use of individual-level data to determine effects at the group level?
Prospective cohort study design23
  1) Representativeness of the exposed cohort  
  2) Selection of the non-exposed cohort
  3) Ascertainment of exposure
  4) Demonstration that outcome of interest was not present at the start of the study
  1) Comparability of cohorts on the basis of the design or analysis controlled for confounders
  1) Assessment of outcome
  2) Was follow-up long enough for outcomes to occur
  3) Adequacy of follow-up of cohorts
Randomized controlled trial study design22
  1) Random sequence generation
  2) Allocation concealment
  3) Selective reporting
  4) Other sources of bias
  5) Blinding (participants and personnel)
  6) Blinding (outcome assessment)
  7) Incomplete outcome
Int J Med Educ. 2021; 12:101-124; doi: 10.5116/ijme.6097.ccc0