Effectiveness of Challenge-Based Instruction in Biomechanics

Journal of Engineering Education, Oct 2006 by Roselli, Robert J, Brophy, Sean P

On the first day of class, students in CBI courses were taught the fundamental principles of HPL, were introduced to the STAR Legacy cycle and classroom communication system, and were provided with the rationale for using challenge-based instruction. They were informed that many of the exercises they would traditionally work for homework would be completed in the classroom and some of the material traditionally covered in lectures would be assigned for homework Data showing the relation between student performance and student participation were also shared with them so they knew the importance of class attendance in a CBI course [25]. Finally, students in both sections of the course were assured that although the instructional modes between classes would be different, the overall course content would be virtually identical.

C. Comparison Studies

A baseline study was conduced during the two years preceding initiation of the current study. In this baseline condition we documented the existing instructional practice (i.e., traditional mode) using the HPL framework as a means to identify opportunities for enhancing the course. Classroom observations and post-lecture interviews with the instructor were conducted by a learning scientist to describe this baseline condition and to identify opportunities where the learning environment might be better informed by HPL methods. In addition, prior final exams were evaluated to identify where students were still weak at the end of the semester. These activities informed the kinds of challenges that were used and the types of supplementary tools that were used to support learning.

For three years after the baseline study we compared the CBI course taught in the Spring semester with the same course taught using the traditional model by a different instructor in the Fall semester. The sophomore class was randomly split in half by the Engineering School Registrar, with one-half taking biomechanics and die other half taking thermodynamics each semester. Each section had approximately 50 students and the student populations had similar demographic compositions and academic credentials. Engineering students at Vanderbilt take mechanics in their physics course during the Spring semester of the first year, so retention might be expected to be greater for students in the Fall sections, but student maturity might be greater in the Spring. To address whether a systematic difference existed between student preparation for Fall versus Spring classes, we gave a pre-test during the first week of class in the first year of the study. Students were asked to draw three free body diagrams involving various types of supports they had encountered in their introductory physics course. A simple rubric was developed that accounted for the presence, orientation, and location of each force and couple on each diagram. We hypothesized that no difference would exist in pre-test performance between the traditional and CBI class. Comparisons were made between classes for each diagram using a two-tailed Student t-test, assuming unequal variance.