Evaluation builds an evidence base for a program when 1 or more studies provide information or data on a program’s effectiveness for a specific target population and set of outcomes. Multiple studies can provide data that can be combined, if they:
- Evaluate the effects of the same program.
- Have the same kind of comparison group (for instance, the comparison group in each study receives treatment-as-usual).
- Look at outcomes that are grouped and measured in similar ways.
- Evaluate the effects of the same program with similar populations.
- Meet similar standards of rigor, such as having low attrition and demonstrating the intervention and comparison groups are very similar or equivalent.
For others to access this information, you must make it publicly available. Many evaluations are published in journals. Others are posted on the Web as comprehensive evaluation reports.