A more detailed description of the review process and study ratings is provided in the review protocol. The protocol was initially written at the start of the review in fall 2009. The study team revised the protocol each time the review findings were updated to include more recent research.
Review Protocol, version 5.0 (613 KB)
This protocol was used to update the review findings to cover research released from July 2014 through October 2016. The protocol also introduced two new changes to the review criteria. First, to remain eligible for the review, programs must now have at least one study that was conducted within the last 20 years and that found positive, statistically significant program impacts. Second, the review team conducted outcome specific assessments of program effectiveness.
Review Protocol, version 4.0 (699 KB)
This protocol was used to update the review findings to cover research released from April 2013 through July 2014. The protocol also added a step for assessing the implementation readiness of programs that have met the review criteria for evidence of effectiveness.
Review Protocol, version 3.0 (709 KB)
This protocol was used to update the review findings to cover research released from January 2011 through April 2013. The protocol also clarified the review criteria related to cluster adjustments, attrition calculations, and effect size information.
Review Protocol, version 2.0 (1 MB)
This protocol was used to update the review findings to cover research released from January 2010 through January 2011. There were no changes to the review criteria.
Review Protocol, version 1.0 (772 KB)
This protocol was used to conduct the initial review of the evidence, which covered research released from 1989 through January 2010.