Preparation for and application to medical school, as well as the subsequent medical training of matriculating students, can have an important impact on psychosocial development. The premedical baccalaureate is the traditional preparation for medical school, although many medical schools also offer a separate entry path through early assurance programs that provide conditional acceptance in the sophomore year of college. These programs may provide freedom in the remainder of the baccalaureate program to explore the liberal arts, which could be a source of differential development of non-cognitive skills among medical students. Self-authorship is defined as the ability to define one's beliefs, identity, and social relations and provides the basis to operate in a complex, ambiguous environment. Such a capacity is relevant to the medical education, where students face changing roles and expectations as they progress through four years of medical school and then graduate training. This study investigated the application of a previously validated quantitative measure of self-authorship across the new population of medical students. Principal component analysis identified a 16-item instrument that measured three dimensions and one phase of self-authorship. Content analysis of responses validated the components. The findings identified the challenges in applying a quantitative measure of self-authorship to medical students. These students may be at a different level of development and require different contexts than those in previous studies. Further research is needed to investigate differences in development across students based upon their entry path to medical school. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]