| Validity Question | Haggerty, 2011 | Taylor, 2008 | Thiele, 2013 | Dawodu, 2012 |
| 1. Was the question for the review clearly focused? | Yes | Yes | Yes | Yes |
| 2. Was the search strategy used to locate studies comprehensive? Were databases and search terms described? | Yes | No (unclear) | Yes | No (unclear) |
| 3. Were explicit methods used to select studies? | No (unclear) | No (unclear) | Yes | No |
| 4. Was there a specified and valid methods for appraisal of quality and validity of studies? | No | No (unclear) | Yes | No |
| 5. Were specific treatments, interventions, exposures described? | No | No (unclear) | Yes | Yes |
| 6. Was the outcome of interest clearly indicated? | Yes | Yes | Yes | Yes |
| 7. Were processes for data abstraction, synthesis and analysis described and applied consistently? Was variation among findings analyzed? Were heterogeneity issues considered? If studies aggregated for meta-analysis, were procedures described? | No (unclear) | No (unclear) | Yes | No (unclear) |
| 8. Were results clearly presented in narrative and/or quantitative terms? | Yes | Yes | Yes | Yes |
| 9. Are conclusions supported by results with biases and limitations taken into consideration? | No | No | No | No |
| 10. Is bias due to study’s funding or sponsorship unlikely? | Yes | Yes | Yes | Yes |