Nursing students need to think critically in order to pass their nursing courses and the critical thinking portion of the national licensure exam. To improve students' critical thinking skills, a nursing program in the southern United States recently required that 4th semester students take a 1-credit critical thinking course. This study evaluated the efficacy of that course objective. Benner's novice to expert theory, which is commonly used in nursing research when examining the development of critical thinking, served as the study's conceptual framework. This quasi-experimental study used a control-group interrupted time-series design to compare the Health Education Systems, Incorporated Assessment exam results of 46 students who did not take a course to the scores from 46 students who were required to take a critical thinking course the following semester. An independent samples t test indicated that students who completed the critical thinking course scored significantly higher than those who did not take the course (p = 0.003). This study contributes to positive social change because the findings support one strategy for developing the key skill of critical thinking among nursing students. This skill contributes to nursing students becoming more patient-centered and self-directed, and therefore, when they become nurses, more capable of caring for patients. [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.]