Critical thinking skills (CTS) have been emphasized in educational curricula and professional development of physical therapists. Studies assessing the measurement and development of CTS in healthcare professionals have primarily focused on students enrolled in professional phases of allied health educational programs. Despite the breadth of research regarding CTS, evidence relating to the level of CTS required for a specific profession and the standardized measures of CTS is inconsistent. The purpose of this study was to explore the differences in CTS between experienced physical therapists and novice physical therapists as assessed by the California Critical Thinking Skills Test (CCTST) (Facione, Facione, & Winterhalter, 2010). The novice group was comprised of 16 therapists, and the experienced group was comprised of 21 therapists. Using a web-based application, all 37 participants completed the CCTST 2000. The t test was used to analyze the group differences in overall CCTST scores and sub-scores of deduction, induction, analysis, inference and evaluation. A Pearson correlation test was used to investigate the relationship between age and experience with respect to the CCTST scores. No statistically significant difference in the overall CCTST score or CCTST sub-scores was noted between the novice group and the experienced group. Mild, but not statistically significant, inverse relationship between age and CCTST overall score and all CCTST sub-scores as well as between years of experience and CCTST overall score and sub-scores of induction, deduction and evaluation was observed. Based upon the consistency of the results from this study with other quantitative studies and the inconsistency of the results from this study with prior qualitative studies, one may conclude that the use of a standardized, discipline neutral quantitative assessment tool is not sufficient to measure CTS in healthcare professionals. In combination with findings from other studies and findings from this study, development of CTS in healthcare providers appears to be dependent upon a complex interdependency of a multitude of factors. Secondary to the limited sample size, one should use caution in generalizing the results from this study to a larger population. [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.]