Serious mental illness (SMI) is a persistent mental health condition that significantly impacts functioning in multiple life domains, especially the work domain (Dunn, Wewiorski, & Rogers, 2010). Difficulties with work functioning and finding or maintaining employment can be detrimental to the health-related quality of life and overall well-being of individuals with SMI. The staggering low rates of employment (20% to 25%) for people with schizophrenia and related disorders exert a heavy health and economic burden to society. In the United States, annual costs are estimated at $ 113 billion on mental health treatment alone (Centers for Disease Control and Prevention, 2011; Mark, Levit, Vandivort-Warren, Buck, & Coffey, 2011; Mechanic, Bilder, & McAlpine, 2002), with the majority of individuals served expressing a desire to secure employment as a recovery goal (National Alliance on Mental Illness, 2015). Effective vocational rehabilitation services can lead to better employment outcomes and community integration for individuals with SMI (Cook et al., 2007), yet these practices are not widespread as only a small minority of those with SMI have access to evidence-based programs in psychiatric rehabilitation (Corrigan, 2004; Substance Abuse and Mental Health Services Administration, 2015).To improve recovery outcomes, the field of mental health is implementing a paradigm shift by encouraging consumers to be self-determined and active participants in all aspects of the treatment and rehabilitation process, including medication, interventions, and employment (Corrigan et ah, 2012). Using principles of self-determination to guide mental health services can foster self-determined motivation, thus reducing mental health symptoms and enhancing treatment engagement (Saperstein, Fiszdon, & Bell, 2011; Strauser, 2014). The theory of self-determination (SDT; Deci & Ryan, 1985) describes how human beings achieve goals, reach self-actualization, and experience a higher quality of life while in treatment, healthcare, or other contexts that support the realization of fundamental human needs, including competency, autonomy, and relatedness or feelings of connectedness to others (Reeve, Nix, & Hamm, 2003; Ryan & Deci, 2000). Self-determined individuals are more capable of dealing with setbacks or difficulties related to their goals, whereas individuals less self-determined are prone to giving up, especially if contingent rewards are removed. For people with SMI, experiencing substantial personal (e.g., premorbid occupational functioning, cognitive functioning, severity of illness) and contextual barriers (e.g., work disincentives, perceived workplace stigma) to gainful employment, can be difficult to overcome without a self-determined recovery goal to sustain engagement in vocational rehabilitation services (Fitzgerald et ah, in press).Competency is a key construct in the SDT framework. In recent research, it has been found to be significantly associated with outcome expectancy, treatment adherence, and vocational rehabilitation outcomes (Chou, Ditchman, Pruett, Chan, & Hunter, 2009; Corbiere, Mercier, & Lesage, 2004; Fitzgerald, Chan et ah, 2015; Ventura, Salanova, & Llorens, 2015). People with SMI, in particular, may encounter negative experiences that contribute to low work-related competence, such as nonworking role models, self-stigma, perceived job discrimination, disruption in education, and unconstructive opinions from co-workers (Corbiere et ah, 2004; Larson, 2008). With longer periods of unemployment, perceived competence declines even further and the barriers to employment may seem insurmountable. Improving one's vocational competency can facilitate the process of overcoming barriers to employment and can result in concrete action steps toward competitive employment. In order to further evaluate and implement practices focusing on self-determination as a framework in psychiatric rehabilitation settings, it is important to develop and validate brief, reliable and valid measures to operationalize competency along with other SDT constructs. …