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NCJ Number: 52180 Find in a Library
Title: QUASI-EXPERIMENTAL APPROACH TO ASSESSING TREATMENT EFFECTS IN THE NONEQUIVALENT CONTROL GROUP DESIGN
Journal: PSYCHOLOGICAL BULLETIN  Volume:82  Issue:3  Dated:(MAY 1975)  Pages:345-362
Author(s): D A KENNY
Corporate Author: American Psychological Assoc
United States of America
Date Published: 1975
Page Count: 18
Sponsoring Agency: American Psychological Assoc
Washington, DC 20002-4242
Harvard University
Cambridge, MA 02138
National Science Foundation
Arlington, VA 22230
Grant Number: GS-30273X
Type: Report (Study/Research)
Format: Article
Language: English
Country: United States of America
Annotation: AFTER A DISCUSSION OF THE POSSIBILITIES FOR SAMPLING ERROR AND BIASED SELECTION WHEN USING NONEQUIVALENT CONTROL GROUP EXPERIMENTAL DESIGN, FOUR STATISTICAL TESTS OF TREATMENT EFFECT ARE EVALUATED.
Abstract: NONEQUIVALENT CONTROL GROUP DESIGN CONSISTS OF PRETREATMENT AND POSTTREATMENT MEASURES OF A DEPENDENT VARIABLE WITH BIASED ASSIGNMENT TO TREATMENT GROUPS. DIFFERENT STATISTICAL TECHNIQUES USED TO ADJUST FOR THIS NONRANDOM ASSIGNMENT ARE THE ANALYSIS OF COVARIANCE, ANALYSIS OF COVARIANCE WITH RELIABILITY CORRECTION, RAW CHANGE SCORE ANALYSIS, AND STANDARDIZED CHANGE SCORE ANALYSIS. THE STRENGTHS AND WEAKNESSES OF EACH TECHNIQUE ARE ASSESSED, AND APPROPRIATE APPLICATION IS ILLUSTRATED. IT IS CONCLUDED THAT IF ASSIGNMENT TO TREATMENT GROUPS IS BASED ON PRETEST SCORES, ANALYSIS OF COVARIANCE IS APPROPRIATE. SELECTION BASED ON STABLE GROUP DIFFERENCES AND SELECTION THAT OCCURS MIDWAY BETWEEN PRETEST AND POSTTEST NECESSITATES CHANGE SCORE ANALYSIS. PROBLEMS WHICH OCCUR WITH RETROSPECTIVE MEASUREMENT OF THE TREATMENT AT POSTTEST AND POSSIBLE RIVAL HYPOTHESES OF CHANGES IN THE TREATMENT-EFFECT CORRELATIONS ARE DISCUSSED. VARIOUS SIGNIFICANCE TESTS PROPOSED BY RESEARCHERS ARE REVIEWED. IT IS WARNED THAT COMPENSATORY EDUCATION PROGRAMS CAN BE MADE TO LOOK MISTAKENLY INEFFECTIVE IF THEY ARE ANALYZED BY AN INAPPROPRIATE STATISTICAL TECHNIQUE RATHER THAN BY STANDARDIZED CHANGE SCORE ANALYSIS. THE USE OF QUASI-EXPERIMENTAL DESIGN AND THE IMPORTANCE OF GOOD STATISTICAL ANALYSIS TO THE EVALUATION OF REAL-WORLD SITUATIONS IS EXAMINED. REFERENCES ARE PROVIDED. TABLES AND FIGURES ILLUSTRATE THE MATHEMATICAL DISCUSSION AND AN APPENDIX DETAILS THE CALCULATIONS SUPPORTING DATA IN ONE OF THE TABLES. (GLR)
Index Term(s): Effectiveness; Evaluation; Evaluative research; Research methods; Statistical analysis; Statistics; Treatment
To cite this abstract, use the following link:
http://www.ncjrs.gov/App/publications/abstract.aspx?ID=52180

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