Analysis of the differential treatment effects across targeted subgroups and contexts is a critical objective in many evaluations because it delineates for whom and under what conditions particular programs, therapies or treatments are effective. Unfortunately, it is unclear how to plan efficient and effective evaluations that include these…

Practitioners and policymakers often want estimates of the effect of an intervention for their local community, e.g., region, state, county. In the ideal, these multiple population average treatment effect (ATE) estimates will be considered in the design of a single randomized trial. Methods for sample selection for generalizing the sample ATE to…

In cluster randomized evaluations, a treatment or intervention is randomly assigned to a set of clusters each with constituent individual units of observations (e.g., student units that attend schools, which are assigned to treatment). One consideration of these designs is how many units are needed per cluster to achieve adequate statistical…

A randomized experiment that measures the impact of a social policy in a sample of the population reveals whether the policy will work on average with universal application. An experiment that includes only the subset of the population that volunteers for the intervention generates narrower "proof-of-concept" evidence of whether the…

The purpose of this paper is to introduce the Five-Level Qualitative Data Analysis (5LQDA) method for ATLAS.ti as a way to intentionally design methodological approaches applicable to the field of evaluation. To demonstrate my analytical process using ATLAS.ti, I use examples from an existing evaluation of a STEM Peer Learning Assistant program.…

The Benefit Offset National Demonstration (BOND) tested a $1 reduction in benefits per $2 earnings increase above the level at which Social Security Disability Insurance benefits drop from full to zero under current law. BOND included a rare and large "population-representative" experiment: It applied the rule to a nationwide, random…

Randomization of large number of participants to different treatment groups is often not a feasible or preferable way to answer questions of immediate interest to professional practice. Single case designs (SCDs) are a class of research designs that are experimental in nature but require only a few participants, all of whom receive the…

Treatment effect estimates from a "regression discontinuity design" (RDD) have high internal validity. However, the arguments that support the design apply to a subpopulation that is narrower and usually different from the population of substantive interest in evaluation research. The disconnect between RDD population and the…

Evidence-based interventions hold promise for reducing gaps in health equity across diverse populations, but evidence about effectiveness within these populations lags behind the mainstream, often leaving opportunities to fulfill this promise unrealized. Mismatch between standard intervention outcomes research methods and the cultural and…

Tiered evidence initiatives are an important federal strategy to incentivize and accelerate the use of rigorous evidence in planning, implementing, and assessing social service investments. The Social Innovation Fund (SIF), a program of the Corporation for National and Community Service, adopted a public-private partnership approach to tiered…

In policy evaluations, interest may focus on why a particular treatment works. One tool for understanding why treatments work is causal mediation analysis. In this essay, I focus on the assumptions needed to estimate mediation effects. I show that there is no "gold standard" method for the identification of causal mediation effects. In…

Interest in the regression discontinuity (RD) design as an alternative to randomized control trials (RCTs) has grown in recent years. There is little practical guidance, however, on conditions that would lead to a successful RD evaluation or the utility of studies with underpowered RD designs. This article describes the use of RD design to…

Heterogeneity between and within people necessitates the need for sequential personalized interventions to optimize individual outcomes. Personalized or adaptive interventions (AIs) are relevant for diseases and maladaptive behavioral trajectories when one intervention is not curative and success of a subsequent intervention may depend on…

This article discusses the nonuse, misuse, and proper use of pilot studies in experimental evaluation research. The authors first show that there is little theoretical, practical, or empirical guidance available to researchers who seek to incorporate pilot studies into experimental evaluation research designs. The authors then discuss how pilot…

Traditionally, evaluation has primarily tried to answer the question "Does a program, service, or policy work?" Recently, more attention is given to questions about variation in program effects and the mechanisms through which program effects occur. Addressing these kinds of questions requires moving beyond assessing average program…