<p>Over the last three decades, there has been a precipitous rise in curiosity regarding the clinical use of mindfulness meditation for the self-management of a broad range of chronic health conditions. Despite the ever-growing body of evidence supporting the use of mindfulness-based therapies for both medical and psychological concerns, data on the active ingredients of these mind-body interventions are relatively scarce. Regular engagement in formal mindfulness practice is considered by many to be requisite for generating therapeutic change; however, previous investigations of at-home practice in MBIs have produced mixed results. The equivocal nature of these findings has been attributed to significant methodological limitations, including the lack of standardized, systematic practice monitoring tools, and a singular focus on practice time, with little attention paid to the nature and quality of one’s practice. The present study used a prospective, observational design to assess the effects of home-based practice on dispositional mindfulness, self-compassion, and psychological functioning in twenty-eight people enrolled in an MBSR or MBCT program. To address some of the aforementioned limitations, the present study collected detailed weekly accounts of participants’ home-based practice engagement, including information about practice time (i.e., frequency and duration), exercise type, perceived effort and barriers to participation, and practice quality. Hierarchical multiple regression was used to examine the relative contribution of practice time and practice quality on treatment outcomes, and to explore possible predictors of adherence to at-home practice recommendations. As anticipated, practice quality and perceived effort improved with time; however, rather unexpectedly, practice quality was not a significant predictor of treatment-related improvements in psychological health. Home practice engagement, however, was predictive of change in dispositional mindfulness, in the expected direction. Results of our secondary analyses demonstrated that employment status was predictive of home practice engagement, with those who were unemployed completing more at-home practice on average. Mindfulness self-efficacy at baseline and previous experience with meditation or other contemplative practices were independently predictive of mean practice quality. The results of this study suggest that home practice helps generate meaningful change in dispositional mindfulness, which is purportedly a key mechanism of action in mindfulness-based interventions.</p> / Dissertation