The What Works Clearinghouse (WWC) Standards Briefs explain the rules the WWC uses to evaluate the quality of studies for practitioners, researchers, and policymakers. This brief explains what baseline equivalence is and why it matters. As part of the WWC review process for certain types of studies, reviewers assess whether the intervention group…

The goal of this paper is to provide guidance for applied education researchers in using multi-level data to study the effects of interventions implemented at the school level. Two primary approaches are currently employed in observational studies of the effect of school-level interventions. One approach employs intact school matching: matching…

Using meta-analysis, randomized experiments in education that either clearly did or clearly did not experience student attrition were examined for the baseline comparability of groups. Results from 35 studies suggested that after attrition, the observed measures of baseline comparability of groups did not differ more than would be expected given…

Despite the hypothesized link between arousal and behavior in persons with autism, there is a lack of idiographic research that directly assesses arousal responses to novel stimuli or social situations in this population. The current study used heart rate as a measure of sympathetic activity to compare arousal responses to the presentation of…

This review and critique of the use of comparison groups in 57 studies of mental retardation family research addresses such issues as: matching on age versus competency of the mentally retarded family member, demographic equivalence of groups, research involving siblings, research involving mentally retarded parents, and appropriateness of…

This paper reviews limitations in the interpretations of group differences in studies that use younger, language-matched controls in addition to age-matched controls to examine the role of "language level" on performance. Problems arise because of the multidimensional nature of language, extraneous age effects associated with language matching,…

Examines groups of conduct-disordered and normal children in order to (1) test the potential usefulness of observational techniques in assessing therapeutic outcomes and (2) identify possible differences between deviant children and normal peers in aggressive and prosocial behavior. (RH)

A meta-analysis was conducted on 44 educational studies that used either a (labelled) Hawthorne control group, a manipulation of Hawthorne effects, or a group designed to control for the Hawthorne effect. The sample included published journal articles, ERIC documents or unpublished papers, and dissertations. The studies were coded on 20 variables,…

This article discusses research design problems peculiar to work with intellectually disabled subjects, such as discrepancies in uses of control groups and mental age matching, definitions of subject groups and variability within and between subject groups. Suggestions for minimizing these problems are made and alternative methodologies offered.…

Ninety-two research reports involving specifically language-impaired subjects were reviewed. Analysis showed few consistent trends with respect to subject selection, subject description, and the number and types of control groups. The importance of more complete subject descriptions and matching criteria for control groups is discussed.…

Based on data gathered during their public elementary school education, two groups of 49 students in private and public schools were matched on age, ethnicity, gender, socioeconomic status and IQ. Their achievement test scores as high school seniors do not support the claim that private schools necessarily effect higher achievement. (BS)

Discusses how clinicians and researchers can critically evaluate information from efficacy studies of language intervention programs. It argues for combining both experimental and nonexperimental approaches and suggests that the use of matching in nonrandomized studies allows for comparison of groups of children participating in an intervention…