Appendix 2.
Assessing the strength of a body of evidence on effectiveness of population-based interventions in the Community Guide, adapted from Briss et ala.
| Evidence of effectivenessb | Quality executionc | Design suitability | Number of studies | Consistentd | Effect sizee |
|---|---|---|---|---|---|
| Strong | Good | Greatest | At least 2 | Yes | Sufficient |
| Good | Greatest or moderate | At least 5 | Yes | Sufficient | |
| Good or fair | Greatest | At least 5 | Yes | Sufficient | |
| Meets execution, suitability, number and consistency criteria for sufficient but not strong evidence | Large | ||||
| Sufficient | Good | Greatest | 1 | Not applicable | Sufficient |
| Good or fair | Greatest or moderate | At least 3 | Yes | Sufficient | |
| Good or fair | Greatest, moderate, or least | At least 5 | Yes | Sufficient | |
| Insufficientf | A. Insufficient design or execution | B. Too few studies | C. Inconsistent | D. Small |
Briss PA et. al. Developing an evidence-based Guide to Community Preventive Services – methods. The Task Force on Community Preventive Services. Am J Prev Med. 2000; 18(1 suppl): 35–43.
The categories are not mutually exclusive; a body of evidence meeting criteria for more than one of these should be categorized in the highest possible category.
Studies with limited execution are not used to assess effectiveness.
Generally consistent in direction and size.
Sufficient and large effect sizes are defined on a case-by-case basis and are based on the GUIA advisory team opinion.
These categories are not mutually exclusive and one or more of these will occur when a body of evidence fails to meet the criteria for strong or sufficient evidence.