Purpose: Improving physicians’ critical thinking abilities could have meaningful impacts on various aspects of routine medical practice, such as choosing treatment plans, making an accurate diagnosis, and reducing medical errors. The present study aimed to measure the effects of a curriculum integrating critical thinking on medical students’ skills at Tehran University of Medical Sciences, Iran. Methods: A 1-group pre-test, post-test quasi-experimental design was used to assess medical students’ critical thinking abilities as they progressed from the first week of medical school to middle of the third year of the undergraduate medical curriculum. Fifty-six participants completed the California Critical Thinking Skills Test twice from 2016 to 2019. Results: Medical students were asked to complete the California Critical Thinking Skills Test the week before their first educational session. The post-test was conducted 6 weeks after the 2 and half-year program. Out of 91 medical students with a mean age of 20±2.8 years who initially participated in the study, 56 completed both the pre- and post-tests. The response rate of this study was 61.5%. The analysis subscale showed the largest change. Significant changes were found in the analysis (P=0.03), evaluation (P=0.04), and inductive reasoning (P<0.0001) subscales, but not in the inference (P=0.28), and deductive reasoning (P=0.42) subscales. There was no significant difference according to gender (P=0.77). Conclusion The findings of this study show that a critical thinking program had a substantial effect on medical students’ analysis, inductive reasoning, and evaluation skills, but negligible effects on their inference and deductive reasoning scores.

Purpose: Improving physicians’ critical thinking abilities could have meaningful impacts on various aspects of routine medical practice, such as choosing treatment plans, making an accurate diagnosis, and reducing medical errors. The present study aimed to measure the effects of a curriculum integrating critical thinking on medical students’ skills at Tehran University of Medical Sciences, Iran. Methods: A 1-group pre-test, post-test quasi-experimental design was used to assess medical students’ critical thinking abilities as they progressed from the first week of medical school to middle of the third year of the undergraduate medical curriculum. Fifty-six participants completed the California Critical Thinking Skills Test twice from 2016 to 2019. Results: Medical students were asked to complete the California Critical Thinking Skills Test the week before their first educational session. The post-test was conducted 6 weeks after the 2 and half-year program. Out of 91 medical students with a mean age of 20±2.8 years who initially participated in the study, 56 completed both the pre- and post-tests. The response rate of this study was 61.5%. The analysis subscale showed the largest change. Significant changes were found in the analysis (P=0.03), evaluation (P=0.04), and inductive reasoning (P<0.0001) subscales, but not in the inference (P=0.28), and deductive reasoning (P=0.42) subscales. There was no significant difference according to gender (P=0.77). Conclusion The findings of this study show that a critical thinking program had a substantial effect on medical students’ analysis, inductive reasoning, and evaluation skills, but negligible effects on their inference and deductive reasoning scores.