The goal of this research study was to assess the effectiveness of the use of the Clinical Integrative Puzzle (CIP) assessment as an online training tool to advance illness script formation for diagnostic problem-solving in the didactic phase of medical education. The main research question in the study was: Is there a statistically significant difference in illness script formation between first-year physician assistant students who use the CIP as a practice tool and first-year physician assistant students who do not use the CIP as a practice tool? The target population was first-year physician assistant students. The methodology of the research study was quasi-experimental. Research participants included first-year PA students from two accredited PA programs in the U.S. Statistical analysis used the multivariate analysis of covariance (MANCOVA) and multiple regression. The test of between-subject effects indicated that significant differences exist between the control group and the experimental in both SCT scores and SCT test-taking time [ F(1,17) = 1.36, alpha < 0.025, partial eta[superscript 2] = 0.074] and [F(1,17) = 1.47, alpha < 0.025, partial eta[superscript 2] = 0.080], respectively. The effect sizes were medium for both variables with eta[superscript 2] = 0.074 and eta[superscript 2] = 0.080. The multiple regression correlation coefficient between CIP engagement and the combined variables of SCT score and SCT test-taking time revealed no statistically significant relationship between the variables [ R[superscript 2] = 0.598, R[superscript 2][subscript adj] = 0.197, F(2,8) = 2.225 with p = 0.170 and alpha < 0.05]. Although the participants in the experimental group utilized the CIP only 1.96 days, the results point to a slightly greater approximation of diagnostic expertise as defined by the speed of accurate diagnosis than the control group. It is, therefore, possible that a more robust use of the CIP in future studies would result in a more significant difference in illness script formation between the experimental group and the control group. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]