Intervention impact is calculated based on population reach and intervention effect size that are rated separately and combined into a single score based on the following:
Reach Score Effect Size Score Combined Intervention Impact Score

1 = Low Reach – The study or studies excluded or probably excluded a high proportion of members of the defined target population (i.e., defined according to demographic and/or risk factor characteristics). The intervention tested was not representative of the target population.

1 – Small 1
3 – Medium 2
5 – Large 3

3 = Moderate Reach – The study or studies excluded or probably excluded a small but significant proportion of members of the defined target population. The intervention tested may be only partially representative of the target population.

1 – Small 2
3 – Medium 3
5 – Large 4

5 = Broad Reach – The study or studies included virtually all relevant members of the defined target population. The intervention tested was representative of the target population.

1 – Small 3
3 – Medium 4
5 – Large 5
Updated: 4/12/2010