A comparison of unguided vs guided case-based instruction on the surgery clerkship

Guided case-based instruction is an effective and efficient means of learning for third year medical students on the surgery clerkship. Compared with an unguided format for teaching biliary disease, we observed greater student satisfaction as well as a more efficient utilization of student as well as faculty time with the guided instruction.

While case-based instruction (CBI) has become an extremely popular teaching modality during the first 2 years of medical school, there has been little published regarding its utilization during the clinical years of medical school. The purpose of our study was to compare guided CBI (G-CBI) to unguided CBI (UG-CBI) during the surgery clerkship.

From July 2007 to July 2008, we utilized a UG-CBI format to teach biliary disease, formerly taught by a standard lecture. The unguided style is used by our institution for the first 2 years of medical school education, where the role of the facilitator is minimal. From July 2008 to December 2010, we changed to a G-CBI format where 5 different clinical scenarios were presented that all dealt with some form of biliary disease. A Likert-like scale was used to analyze student opinion comparing guided to the traditional unguided format. Questions regarding biliary disease contained in the National Board of Medical Examiners (NBME) shelf examination, given to all students at the end of the rotation, were also compared between the 2 groups. Cohen's d statistic was used to assess effect size.

The study took place at the University of Arizona College of Medicine.

There were 88 students in the UG-CBI group and 146 in the G-CBI group.

Ninety-six percent of the students preferred G-CBI over the unguided format utilized during the basic science years. Eighty-two percent felt that the guided format sessions were a more efficient method of instruction and 91% of students agreed or strongly agreed that time was more efficiently utilized in preparing for the case discussion during the guided format. Shelf examination scores analyzing biliary disease questions (2-4 per examination) showed a moderate size effect favoring the G-CBI, although the numbers were too small to draw definite conclusions in this regard.

G-CBI is more suited for the surgery clerkship than the UG-CBI utilized during the first 2 years of medical school. Lack of a clinical knowledge base among the students rotating on the surgery clerkship as well as time limitations for both the student and clinical faculty favor this more efficient means of learning.