Intervention Description

• Clear description of key aspects of the intervention

Quality–Study design

• Prospective study design
• Appropriate and concurrent comparison arm, or historical comparison (provided it is similar to intervention arm with respect to population, setting, time frame in the epidemic, and identical with respect to follow-up interval, recall period, and outcome measures)
• Random, minimally biased, or moderately biased assignment of subjects to study arms, allowing for selection bias unrelated to the intervention or HIV risk. Assignment may be based on pre-established groups or selection into something other than the intervention, provided neither are directly related to HIV risk.

Quality–Study implementation and analysis

• At least a 1-month postintervention follow-up assessment for each study arm (with recall referring to postintervention period only)
• At least a 60% retention rate at a single follow-up for each study arm
• Comparison between intervention arm and an appropriate comparison arm
• Analysis of subjects in study arms as originally assigned, or subjects may be excluded if contamination occurs, but subjects may not be re-assigned for analytical purposes
• Analysis of subjects may be based on intervention exposure, where subjects exposed to ≤ 50% of the entire intended intervention may be excluded
• If subjects excluded due to contamination or low exposure (as described above), retention rate must be calculated based on those retained for analyses
• Analysis must be based on postintervention levels or among pre-post changes in measures
• For pre-post changes used in analysis, measures must be identical, including identical recall period
• Analysis based on an α =.05 and either a 2-sided test or 1-sided test if an a-priori direction is hypothesized
• In nonrandomized assignment, either no statistical differences in baseline levels of the outcome exist or baseline differences are controlled for in the analysis. If moderately biased assignment exists or historical comparison was used, then baseline demographics and outcome variables must be controlled for in the analysis.

Strength of Evidence–Significant positive intervention effects

• Positive and statistically significant (p ≤ .05) intervention effect for ≥ 1 relevant outcome measure
  • A positive intervention effect is defined as a greater reduction in HIV/STD incidence or risk behaviors or a greater increase in HIV protective behaviors in the intervention arm relative to the comparison arm.
  • A relevant outcome is defined as a behavior (e.g., abstinence, mutual monogamy, number of sex partners, negotiating safer sex, condom use, injection drug use, HIV testing behaviors) that directly impacts HIV risk or a biologic measure indicating HIV or STD infection (i.e., HIV or STD incidence)
• Effect at the follow-up and based on the analyses that meet study implementation and analysis criteria

Strength of Evidence–Negative intervention effects

• No negative and statistically significant (p < .05) intervention effect for any relevant outcome (A negative intervention effect is defined as a greater increase in HIV/STD incidence or risk behaviors or a greater decrease in HIV protective behaviors in the intervention arm relative to the comparison arm.)
• No other statistically significant harmful intervention effect
• For an intervention with a replication evaluation, no significant negative intervention effects in the replication study

Overall fatal flaw

• No evidence that any additional limitation was a fatal flaw
  • A fatal flaw has occurred when the limitation is thought to introduce considerable bias, thus substantially reducing the confidence of the findings
  • Examples of fatal flaws include: small sample size (< 40 participants per study arm); effects only found within a potentially biased subset analyses; substantial missing data

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