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…

In experimental research, internal validity refers to what extent researchers can conclude that changes in dependent variable (i.e. outcome) are caused by manipulations in independent variable. The causal inference permits researchers to meaningfully interpret research results. This article discusses (a) internal validity threats in social and…

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…

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…

Organizational and applied sciences have long struggled with improving causal inference in quasi-experiments. We introduce organizational researchers to propensity scoring, a statistical technique that has become popular in other applied sciences as a means for improving internal validity. Propensity scoring statistically models how individuals in…

Educational researchers frequently study the impact of treatments or interventions on educational outcomes. However, when observational or quasiexperimental data are used for such investigations, selection bias can adversely impact researchers' abilities to make causal inferences about treatment effects. One way to deal with selection bias is to…

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…

Few research studies have investigated the effectiveness of instructional strategies for students in juvenile corrections. The dearth of research on effective instruction for this population may be due in part to difficulties encountered in carrying out methodologically rigorous studies in these settings. This article reports barriers and…

This article discusses the difficulties in conducting intervention research or evaluating intervention programs in a school setting. In particular, the problems associated with randomization and obtaining control groups are examined. The use of quasi-experimental designs, specifically a paired comparison design using the individual as his or her…

Describes problems in implementing placebo controls in psychotherapy including the difficulty of ensuring that therapists and their patients will view both the experimental and placebo treatments as comparably credible. Considers six research issues stemming from the definitional requirement that the placebo control for the critical and specific…

Reviews empirical studies of suicide survivors with designs that include control groups. Discusses investigations individually with respect to those in which participating survivors are friends or combination of different relationships to deceased, parents of deceased child, and spouses. Discusses commonalities of findings and most frequent…

Identifies and discusses three myths that pervade experimental counseling and psychotherapy: (1) that experimental subjects receive treatments appropriate to their clinical problems; (2) that the treatments are deployed as purported; and (3) that control groups customarily used by researchers allow them to determine the existence of a treatment…

An examination of the scientific basis of both control group designs and comparative designs in outcome research reveals that comparative designs generally have fewer threats to validity and provide a more efficient means of control for nonspecific treatment factors suggesting that comparative studies warrant a larger role in the study of…

This article discusses the use of propensity scoring in experimental program evaluations to estimate impacts for subgroups defined by program features and participants' program experiences. The authors discuss estimation issues and provide specification tests. They also discuss the use of an overlooked data collection design--obtaining predictions…

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…