Date of Award


Degree Type


Degree Name

Doctor of Philosophy in Psychology



First Advisor

Joseph S. Rossi


A growing number of researchers are searching for ways of integrate existing knowledge of the psychotherapy process from disparate theoretical orientations. The Transtheoretical Model of Change has been proposed by Prochaska and DiClemente as a means of providing a conceptual integration of the theoretically fragmented field of psychotherapy. Primary goals of the current study were to investigate the psychometric properties and to refine the content of seven paper and pencil instruments designed to measure key constructs associated with the Transtheoretical Model, and to use data associated with the refined instruments to investigate theoretically proposed relationships between the measured constructs.

Analysis of psychotherapy client data (N = 337) associated with the Processes of Change Questionnaire resulted in a refined, nine scale, 25-item version of this measure. An expanded 78-item version of this questionnaire which attempts to assess frequency of use of twelve hypothesized processes of change is proposed for future use. Responses to the Processes of Change (Within Sessions) Questionnaire for therapy clients (N = 102) and therapists (N = 108) were analyzed with results suggesting that these parallel 10-item measures could best be viewed as assessing frequency of general within-session process of change use. Client data (N = 310) associated with the Stages of Change Questionnaire were analyzed, resulting in a refined, four scale, 18-item version of this measure. Psychotherapy client and self-change subject (N = 170) responses, and therapist (N = 250) responses to separate versions of the Levels of Attribution and Change Questionnaire were analyzed, resulting in refined, ten scale, 33-item client and therapist versions of these measures. A final scale refinement procedure imposed on data from clients and self-changers (N = 137) resulted in a two scale, 12-item Decisional Balance Questionnaire.

Several theoretically postulated relationships between the constructs assessed by these measures were investigated, and, in general, results were supportive of the applicability of the Transtheoretical Model to change within psychotherapy. Implications of this work, both within the context of the Transtheoretical Model, as well as within the context of psychotherapy research, in general, are discussed, as are recommendations for future research.



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