Table 1.

Issues in Moving from Efficacy to Effectiveness Trials in Prevention Research

	Efficacy	Effectiveness
Program of Research	Beginning with carefully controlled efficacy trials provides internal validity but limits generalizability, requires more steps to reach effectiveness and implementation.	Beginning with efficacy/effectiveness hybrids or pragmatic trials maintains some experimental control and also includes elements needed to understand effects in real-world contexts; more generalizable.
Intervention Design and Conceptualization	Most common design is a carefully controlled, randomized trial designed to isolate the intervention as the main source of variability. Often little attention to generalizability or transportability. Interventions should be grounded in theory.	Designs incorporate more variability in participants, interventionists, and settings; are sometimes not randomized. Ability to be implemented and engage participants in real world settings must be considered. Interventions should be grounded in theory and may include a motivational component.
Participant Selection & Characteristics	Smaller sample size. Self-selected, paid volunteers or defined sub-population. Homogeneous sample in terms of geography, community, risk factors, or other variables. Researchers in charge of recruitment of individuals or participating entities.	Larger sample size. Self-selected, paid or unpaid volunteers or defined sub-population. Heterogeneous sample needed to test generalizability, sociocultural differences in response to intervention, differential outcomes based on initial risk, and other variables. Agency personnel may assume recruitment.
Intervention Providers	Carefully trained research assistants or other individuals familiar with and committed to intervention, usually with adequate time to prepare and provide intervention.	Community lay persons or professionals in related fields with intervention-specific training who may have conflicting theoretical orientations to change and competing job duties that result in limited time for prevention and supervision.
Intervention Delivery Context	Defined location(s), such as research lab or specific classroom.	Multiple locations.
Measurement & Methodology	Randomized controlled trial (RCT) is gold standard. Assessment may be lengthy. Researchers track participants closely, minimize attrition and procedural irregularities.	Alternatives to RCT’s may be used. Assessments must be streamlined. Researchers prepare for attrition, irregularities due to multiple providers and stakeholders.
Selection of Outcomes	Primary outcome of interest is whether intervention produces preventive effects post-intervention and at variable follow-up periods.	Outcomes include preventive effects of intervention, fidelity of implementation across settings, feasibility of implementation by community providers, moderating effects, and other outcomes related to implementation and feasibility.
Cost	Often not considered at this stage of research. Intervention is generally fully supported by grant budget.	Measurement of costs of intervention delivery and estimation of cost savings of preventing negative outcomes are recommended. Intervention may be partially or fully self-supported.
Sustainability within Communities	Often not considered at this stage of research.	Feasibility within community agencies, acceptability to community members, attractiveness to providers, and other factors must be considered.