Five methods for computing significant individual client change and improvement rates: support for an individual growth curve approach.
Interest has been renewed in methods for determining individual client change. Currently, there are at least 4 pretreatment-posttreatment (pre-post) difference score methods. A 5th method, based on a random effects model and multiwave data, represents a growth curve approach and was hypothesized to be more sensitive to detecting significant (p < .05) change than the pre-post methods. The change rates produced by the 5 methods were compared in a sample of 73 older outpatients with 3 to 5 assessments per client on a measure of well-being (H. J. Dupuy, 1977). Results indicated that the growth curve approach improvement rate was the highest (68.5%). The growth curve and the Edwards-Nunnally (63.0%) methods produced significantly (p < .05) higher improvement rates than the other 3 methods, with 1 exception.
Speer
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DC
Department of Aging and Mental Health, Florida Mental Health Institute, University of South Florida, Tampa 33612-3899, USA.
Greenbaum
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PE
D000223:Adaptation, Psychological; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007206:Individuality; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D010552:Personality Assessment / Q000706:statistics & numerical data*; D010553:Personality Development; D011594:Psychometrics; D011613:Psychotherapy; D011788:Quality of Life; D016896:Treatment Outcome