Graduates from three Northern California private universities K-12 teacher preparation programs were invited to participate in an online survey to share their perceptions of the California Teaching Performance Assessment (CalTPA) as it influenced their K-12 beginning teacher practice. Self-selected respondents further volunteered to discuss their experiences in small, researcher-led focus groups. The survey data and focus group transcripts were analyzed using the framework of Mezirow's (1991, 1997, 2000) Adult Transformational Learning Theory to identify factors most influential to forming beginning teachers' habits of mind. The focus group conversations provided personal and critically reflective perspectives that added to the knowledge base of how points of view and habits of minds were altered through the completion of the CalTPA. Evidence collected showed the CalTPA was instrumental in developing teacher candidates understanding of students in their classrooms, adaptations needed to encourage student learning, and the perceived importance of analyzing student work to determine whether students actually were learning what teacher candidates thought they were teaching. Conclusions drawn from this research indicated (a) the CalTPA became a teaching tool by which teacher candidates cohered prior learning from their teacher preparation course and field work, and (b) through completing the CalTPA many teacher candidates were able to transform preconceived beliefs and assumptions about K-12 classroom teaching. [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.]