The research aim is to contribute to scholarly inquiry on best practices for institutional leaders in health care organizations who are leading improvement work. The goal is to investigate how a specific sustainable continuous improvement methodology--lean management (LM)--is experienced by leaders charged with implementing it to improve health care locally. Adult development can be understood as stage-based theory of growth across the human life-span and has been successfully applied to enhance understanding of how adults approach uncertainty and complexity, yet it has not been applied to understand how institutional leaders go about understanding, implementing, and leading improvement work via LM. The primary research focus is how improvement leaders in an academic health care organization describe the implementation experience of LM and how, if at all, LM varies as a function of improvement leaders' stage of development, as represented by their assessed action-logic. This study represents the first step in an exploratory agenda to integrate adult developmental theory with LM application in health care by first understanding how LM's application in hospital settings may vary with individual project leaders' stages of development and how their descriptions of LM implementations during key implementation points within an advanced and internally offered Black Belt training program may match the intent of LM as a systemic, principle-based approach to health care change within an organization implementing it as organization-wide strategy for improvement. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]