Causal effects are commonly defined as comparisons of the potential outcomes under treatment and control, but this definition is threatened by the possibility that either the treatment or the control condition is not well defined, existing instead in more than one version. This is often a real possibility in nonexperimental or observational…

There are few high-quality studies using randomized controlled trials (RCTs) in the adventure and wilderness therapy literature. Thus, a unison call is heard for more such studies to be carried out. This article presents a Norwegian wilderness therapy research project that planned to incorporate this "gold standard" that is regarded as…

Meta-analyses are syntheses of effect-size estimates obtained from a collection of studies to summarize a particular field or topic (Hedges, 1992; Lipsey & Wilson, 2001). These reviews are used to integrate knowledge that can inform both scientific inquiry and public policy, therefore it is important to ensure that the estimates of the effect…

The studies in this special section of the "Journal of Educational Psychology" present a variety of social-psychological interventions across large numbers of classrooms and populations. They show notable benefits for many students at risk for low performance. This is the glass half-full interpretation, and we consider the strengths of…

Randomized controlled trials (RCTs) and regression discontinuity (RD) studies both provide estimates of causal effects. A major difference between the two is that RD only estimates local average treatment effects (LATE) near the cutoff point of the forcing variable. This has been cited as a drawback to RD designs (Cook & Wong, 2008).…

As a result of the 1998 reauthorization of Head Start, the Department of Health and Human Services conducted a national evaluation of the Head Start program. The goal of Head Start is to improve the school readiness skills of low-income children in the United States. There is a substantial body of experimental and correlational research that has…

This "What Works Clearinghouse Procedures and Standards Handbook (Version 3.0)" provides a detailed description of the standards and procedures of the What Works Clearinghouse (WWC). The remaining chapters of this Handbook are organized to take the reader through the basic steps that the WWC uses to develop a review protocol, identify…

Introduction: A correspondence has been seen between the level at which one can read scientific texts and his/her performance in writing this type of texts. Besides being able to read at the most complex levels, formulating research problems requires explicit training in writing. The objective of the present study was to evaluate whether…

Education research rarely lends itself to large scale experimental research and true randomization, leaving the researcher to quasi-experimental designs. The problem with quasi-experimental research is that underlying factors may impact group selection and lead to potentially biased results. One way to minimize the impact of non-randomization is…

This paper introduces an empirical strategy to estimate dynamic treatment effects in randomized trials that provide treatment in multiple stages and in which various noncompliance problems arise such as attrition and selective transitions between treatment and control groups. Our approach is applied to the highly influential four year randomized…

The third-year evaluation of the federally funded Washington, D.C. voucher program shows that low-income students offered vouchers in the first two years of the program had modestly higher reading scores after three years but showed no significant difference in mathematics. Students were randomly assigned to treatment and control groups, and the…

This article examines the effectiveness of incentives in improving survey response rates of school counselors and compares the findings with those of previously researched populations. A $1 cash incentive increased response rates for a one-wave mailing of a questionnaire, while a raffle opportunity did not. The number and length of optional…

The use of analysis of variance was examined under the assumption that the treatment had been randomly assigned to students, when in fact, the class had been the unit. Data support the idea that if one can randomly assign treatments to intact classes, consideration should certainly be given to doing so. (Author/GK)

Employed a developmental context to discuss the problem of assessing both quantitative and qualitative deficits in the behavioral profiles of various diagnostic subcategories of developmentally disabled children. Methods of appropriate matching of control groups are suggested to help delineate specific and general deficits in subgroups of…

Criteria for suitable research designs for use with large databases are suggested and analyzed. The advantages and disadvantages of several types of quasi-experimental designs are compared. Examples are taken from the authors' research with data from the Manitoba Health Services Commission. (Author/AL)