Skip directly to local search Skip directly to A to Z list Skip directly to navigation Skip directly to site content Skip directly to page options
CDC Home

PRS Efficacy Criteria for Best-Evidence (Tier I) Risk Reduction (RR) Community-level Interventions (CLIs)

Intervention Description

  • Clear description of key aspects of the intervention

Quality–Study design

  • Prospective study design
  • Appropriate and concurrent control/comparison arm
  • ≥ 4 communities per arm or appropriate power analysis indicating that a smaller number of communities was adequate (i.e., 2 or 3 communities per arm)
  • Select similar communities (units) for assignment
    • To minimize selection bias before assignment regardless of assignment methods (randomization or not); use methods such as systematic, a-priori approaches to choose intervention and control communities that are similar (e.g., matching or stratification on factors related to important/appropriate community characteristics)

Quality–Study implementation and analysis

  • Sample individuals from assigned communities in acceptable ways (e.g., random, systematic) and use identical methods and eligibility criteria for selecting participants in each community, study arm, and data collection wave
    • If demographic differences are identified a priori, differential selection (e.g., over-sampling based on demographics) may be used to achieve equivalence between study arms on those factors
  • Follow-up assessment ≥ 3 months post completion of entire time-specific CLI or post full implementation of on-going CLI with recall not referring to pre-intervention period
    • “Post full implementation of an on-going CLI” means after all components of the CLI have been started or put in place in communities
  • If cohort, at least 70% retention rate at a single follow-up assessment for each study arm
    • If cohort chart review, ≥ 70% success rate in matching medical records
  • Comparison between intervention arm and an appropriate comparison arm
  • Analysis of communities (units) and analysis of individuals within the communities as originally assigned regardless of contamination or logistic/implementation issues
  • Analysis of communities (units) regardless of community level of intervention exposure
  • Analysis of individuals within the communities (units) regardless of individual level of intervention exposure
  • Use of appropriate cluster-level analyses, e.g., adjusting for ICC
  • 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 a=.05 (or more stringent) and a 2-sided test
  • Either no statistical differences in baseline levels of the outcome exist or baseline differences are controlled for in the analysis, regardless of allocation method (e.g., randomization, non-randomization)
    • No differences on baseline levels of the outcome means reporting no significant difference between groups on BL relevant outcomes or match/stratify/statistically adjust participant data by using propensity scores or relevant outcome covariates (regardless of assignment methods - RCT or non-RCT)

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, consistent condom use with anal/vaginal sex, unprotected anal/vaginal sex, proportion of anal/vaginal sex acts protected, injection drug use, sharing or borrowing needles/works) 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

Additional Limitations to Evaluate:

  • No evidence that additional limitations resulted in a fatal flaw:
    • A fatal flaw has occurred when the overall evaluation of limitations resulted in considerable bias, thus substantially reducing the confidence of the findings
    • Examples of limitations to check for possible fatal flaw:
      • Group non-equivalence in baseline measures of important demographics or risk factors
      • Differential Retention (for cohort studies): (1) association between study arms and characteristics related to retention or attrition; OR (2) more than minimal rate of differential retention (> 10%)
      • Differential Refusal: At baseline for cohort studies; by wave for serial cross-sectional studies: (1) association between study arms and characteristics related to refusal; OR (2) more than minimal rate of differential refusal rate (> 100)
      • Intervention activities did not match with the intervention concepts or guiding theories intended to produce the desired outcomes
      • Did not clearly describe issues related to generalizability
      • Effects only found within a potentially biased subset analyses
      • Substantial missing data (> 10% or missing data plus loss to attrition does not exceed acceptable limits for retention alone)
      • Too many post hoc analyses (even with Bonferrroni corrections)
      • Pilot study or very small sample size per study arm (< 50)

Back to Efficacy Criteria

Top of Page

 

Get Tested


Find an HIV testing site near you.

Search location, such as: "Atlanta, GA", or "30033".

For more information, please visit gettested.cdc.gov

Please contact GETTESTED-Webmaster@cdc.gov with any comments, suggestions, or concerns.


Syndicate This Content Podcast button Tell us what you think button CDC-INFO
USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO