Preventing Mental, Emotional, and Behavioral Disorders Among Young People:  Progress and Possibilities (2009)

Recommendation on Criteria for Establishing Strong Evidence of Effectiveness¹

“Federal and state agencies should prioritize the use of evidence-based programs and promote the rigorous evaluation of prevention and promotion programs in a variety of settings in order to increase the knowledge base of what works, for whom, and under what conditions.  The definition of evidence-based should be determined by applying established scientific criteria.

In applying scientific criteria, the agencies should consider the following standards:

• Evidence for efficacy or effectiveness of prevention and promotion programs should be based on designs that provide significant confidence in the results.  The highest level of confidence is provided by multiple, well-conducted randomized experimental trials, and their combined inferences should be used in most cases.  Single trials that randomize individuals, places (e.g. schools), or time (e.g., wait-list or some times-series designs), can all contribute to this type of strong evidence for examining intervention impact.
• When evaluations with such experimental designs are not available, evidence for efficacy or effectiveness cannot be considered definitive, even if based on the next strongest designs, including those with at least one matched comparison.  Designs that have no control group (e.g., pre-post comparisons) are even weaker.
• Programs that have widespread community support as meeting community needs should be subject to experimental evaluations before being considered evidence-based.
• Priority should be given to programs with evidence of effectiveness in real-world environments, reasonable cost, and manuals or other materials available to guide implementation with a high level of fidelity.”