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…

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…

The Hawthorne and placebo effects in educational experiments were examined over a 20-year period, as reported in the ERIC, Dissertation Abstracts International, and Psych Info data bases. The literature searches identified 325 studies in education employing the relevant control procedures, and each study was coded for the type of placebo…

Discussed problems and deficiencies in past research on clinical diagnosis, pertaining to sampling problems with regard to clinical subjects studied, adequacy of control groups, base rates, clinical versus statistical significance, lack of cross-validation, and problems due to reliance on inadequate schemes of classification. Future research is…

Concluded that studies of coaching for the Scholastic Aptitude Test were methodologically flawed but that some definite regularities could be identified. These regularities indicated size of score effects was related to amount of student contact time in coaching programs. (Author/DB)

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.…

This review focuses on the effects of multiple contacts with respondents on studies of response rates to mail surveys. After screening articles on research criteria, such as the presence of original research and sufficient reporting detail, 28 studies remained of the original 208 identified. The difference in response rate between treatment and…

The Walsh and Carballo evaluation of the effectiveness of transitional bilingual education programs in five Massachusetts communities, has the following flaws: (1) the sample of school districts studied suffered from "self-selection bias"; (2) the sample does not include a single large, urban school district; (3) the student samples…

This article assimilates and critically reviews 10 reports between 1960 and 1980 in which hypnosis was used with non-retarded children, aged 6 to 17, who had learning problems. Studies are reviewed in terms of the major deficit focused on by the researchers, i.e., reading deficits, self-concept and academic achievement, academic behavior problems,…

H.H. Spitz argues that interesting results from the preschool intervention of the Abecedarian Project continue to be disregarded. C.T. Ramey reiterates his earlier objections to Spitz's conclusions, and H.H. Spitz rejoins with specific objections to Ramey. (SLD)

Reexamines definitions of and explanations for the Hawthorne Effect in research subjects. Notes that the Hawthorne Effect was tested in a study of the effectiveness of paired classroom reading among students. Challenges the notion that subject's behavior is modified by participation in research. Reviews various research studies that question the…

A review of the literature suggests that choice of control group may have affected the policy implications of the major evaluations of governmental training programs. It is argued that the usual evaluation designs underadjust for preprogram differences between trainees and the control group and thus yield biased estimates of program impact.…

A meta analysis of 93 research reports on school desegregation and black achievement was conducted to determine (1) why the study results differed as to apparent desegregation effects; and (2) whether some desegregation plans produced greater achievement gains than others. An analysis indicated that inconsistencies in research findings were mainly…

The Elementary and Secondary Education Act Title I Evaluation and Reporting System is a method for giving a federally funded project in reading or math an overall score on its cognitive effectiveness. This System introduced the Normal Curve Equivalent (NCE) as an aid in aggregating Title I program scores across states and nationwide regardless of…