Table 2 Risk of bias assessment tool (adapted from the Risk of Bias Tool for Prevalence Studies developed by Hoy et al. [24])
Risk of bias item | Response: Yes (Low Risk) or No (High risk) |
|---|---|
External Validity | |
1. Was the study target population a close representation of the national population in relation to relevant variables? | |
2. Was the sampling frame a true or close representation of the target population? | |
3. Was some form of random selection used to select the sample, OR, was a census undertaken? | |
4. Was the likelihood of non-participation bias minimal? | |
Internal Validity | |
5. Were data collected directly from the subjects (as opposed to medical records)? | |
6. Was an acceptable case definition used in the study? | |
7. Was the study instrument that measured the parameter of interest (e.g. prevalence of adolescent pregnancy) shown to have reliability and validity (if necessary)? | |
8. Was the same mode of data collection used for all subjects? | |
9. Was the length of the shortest prevalence period for the parameter of interest appropriate? | |
10. Were the numerator(s) and denominator(s) for the calculation of the prevalence of adolescent pregnancy appropriate? | |
11. Summary item on the overall risk of study bias Low Risk of Bias: 8 or more “yes” answers. Further research is very unlikely to change our confidence in the estimate. Moderate Risk of Bias: 6 to 7 “yes” answers. Further research is likely to have an important impact on our confidence in the estimate and may change the estimate. High Risk of Bias: 5 or fewer “yes” answers. Further research is very likely to have an important impact on our confidence in the estimate and is likely to change the estimate | |