Purpose: Recently, the American College of Graduate Medical Education included medical decision-making as a core competency in several specialties. To date, the ability to demonstrate and measure a pedagogical evolution of medical judgment in a medical education program has been limited. In this study, we aim to examine differences in medical decision-making of physician groups in distinctly different stages of their postgraduate career., Methods: The study recruited physicians with a wide spectrum of disciplines and levels of experience to take part in 4 medical simulations divided into 2 categories, abdominal pain (biliary colic [BC] and renal colic [RC]) or chest pain (cardiac ischemia with ST-segment elevation myocardial infarction [STEMI] and pneumothorax [PTX]). Evaluation of medical decision-making used the Medical Judgment Metric (MJM). The targeted selection criteria for the physician groups are administrative physicians (APs), representing those with the most experience but whose current duties are largely administrative; resident physicians (RPs), those enrolled in postgraduate medical or surgical training; and mastery level physicians (MPs), those deemed to have mastery level experience. The study measured participant demographics, physiological responses, medical judgment scores, and simulation time to case resolution. Outcome differences were analyzed using Fisher exact tests with post hoc Bonferroni-adjusted z tests and single-factor analysis of variance F tests with post hoc Tukey honestly significant difference, as appropriate. The significance threshold was set at P < .05. Effect sizes were determined and reported to inform future studies., Results: A total of n = 30 physicians were recruited for the study with n = 10 participants in each physician group. No significant differences were found in baseline demographics between groups. Analysis of simulations showed a significant ( P = .002) interaction for total simulation time between groups RP: 6.2 minutes (±1.58); MP: 8.7 minutes (±2.46); and AP: 10.3 minutes (±2.78). The AP MJM scores, 12.3 (±2.66), for the RC simulation were significantly ( P = .010) lower than the RP 14.7 (±1.15) and MP 14.7 (±1.15) MJM scores. Analysis of simulated patient outcomes showed that the AP group was significantly less likely to stabilize the participant in the RC simulation than MP and RP groups ( P = .040). While not significant, all MJM scores for the AP group were lower in the BC, STEMI, and PTX simulations compared with the RP and MP groups., Conclusions: Physicians in distinctly different stages of their respective postgraduate career differed in several domains when assessed through a consistent high-fidelity medical simulation program. Further studies are warranted to accurately assess pedagogical differences over the medical judgment lifespan of a physician., Competing Interests: Declaration of Conflicting Interests:The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: For M.L.M.C., R.L.G., and R.A.A., a percentage of time was paid by the subcontract grant with Zin Technologies, Inc. M.D.G. and A.S. served as a consultant paid by the subcontract grant with Zin Technologies, Inc. The other authors declared no potential conflict of interest to disclose., (© The Author(s) 2020.)