Patient- focused research is a methodology that involves the regular measurement of patient progress in treatment and the provision of feedback to clinicians to allow modification of interventions to maximize outcomes. A critical component of patient focused research endeavors is the availability of psychometrically sound assessment questionnaires, and one such measure is the Outcome Questionnaire (OQ-45.2). This investigation was comprised of three studies. Study 1 examined the factor structure and internal consistency of the Progress Questionnaire (PQ), an adaptation of the OQ-45.2, in 278 patients seeking psychotherapy and/or medication management services at a large, urban outpatient mental health clinic. Study 2 examined the factor structure and internal consistency of the OQ-45.2 in a sample of 450 patients receiving outpatient psychotherapy in numerous locations. Study 3 examined the temporal stability of the factor structure of the OQ-45.2. The PQ and OQ-45.2 were found to possess desirable estimates of internal consistency, similar to those previously reported for the OQ-45.2. The theoretically derived three factor structure of the OQ-45.2 was submitted to Confirmatory Factor Analysis (CFA) and found to be implausible for the PQ and the OQ-45.2. The studies next turned to exploratory procedures so as to investigate the empirical factor structures of the questionnaires. Results of a Principle Components Analysis (PCA) with Promax rotation revealed that the PQ was comprised of ten correlated factors accounting for 60% of the observed variance. Similarly, the OQ-45.2 was comprised of nine correlated factors accounting for 62% of the observed variance. The sample size in Study 2 permitted validation of this factor structure through CFA. The nine factor model provided significantly improved fit to the three factor model previously tested but was still implausible. Study 3 found that the ninefactor structure obtained with baseline data was not stable when imposed on a sample of data from the fourth assessment. The results suggest that the PQ is statistically less effective than the OQ-45.2, and further use of the modified version is not recommended. Possible explanations for the poor fit of the factor structures are offered, and guidelines are provided for future psychometric studies examining the OQ-45.2.Ph.D., Clinical Psychology -- Drexel University, 200