Pathology

Intervention (counseling)

Internal validity

Clinical psychology

Risk analysis (engineering)

Engineering

Nursing

External validity

Psychology

Psychometrics

Process management

Reliability engineering

Computer science

Management science

Face validity

Medicine

Social psychology

Annual Review of Public Health

Interventional researchers face many design challenges when assessing intervention implementation in real-world settings. Intervention implementation requires holding fast on internal validity needs while incorporating external validity considerations (such as uptake by diverse subpopulations, acceptability, cost, and sustainability). Quasi-experimental designs (QEDs) are increasingly employed to achieve a balance between internal and external validity. Although these designs are often referred to and summarized in terms of logistical benefits, there is still uncertainty about (a) selecting from among various QEDs and (b) developing strategies to strengthen the internal and external validity of QEDs. We focus here on commonly used QEDs (prepost designs with nonequivalent control groups, interrupted time series, and stepped-wedge designs) and discuss several variants that maximize internal and external validity at the design, execution and implementation, and analysis stages.

Selecting and Improving Quasi-Experimental Designs in Effectiveness and Implementation Research