Chestnut Global Partners developed the coaching version of the Workplace Outcome Suite (WOS) to measure the effectiveness of coaching interventions in helping to address a range of workplace issues. For this purpose the original 25-item version of the WOS, developed in 2009, was slightly modified to provide outcome information on the coaching process. While the changes were modest, there was some concern that they might adversely affect the psychometric characteristics of the 25-item tool compromising its validity and reliability. Prudence requires the coaching version of the WOS be evaluated to assure results are equivalent with those of the original WOS. Data from 309 clients, provided with disease management coaching services for depression and diabetes, were analyzed. Various methods, including reliability analysis, confirmatory factor analysis, and correlational studies, were included in the study. The results of these analyses showed that the coaching tool performed slightly better than the original WOS. The instrument was shown to be extremely reliable, particularly for a short scale. The analysis revealed that the 25-item coaching version of the WOS can be used to test the efficacy and effectiveness of a coaching program without concern for significant measurement error. Results suggest that psychometric studies of the original 25-item WOS can also reflect clinical change from the workplace health programs coaching version even with samples as small as 50 clients.