Problem-based learning instruction versus traditional instruction on self-directed learning, motivation, and grades of undergraduate computer science students

A problem-based learning (PBL) teaching method was compared with a traditional lecture-based teaching method to determine the effects on undergraduate Computer Science (CS) students' self-directed learning (SDL) and programming assignment grades. An integrated construct of SDL included (a) SDL readiness, (b) SDL skills, (c) SDL performance, and (d) students' course motivation. Quasi-experimental designs were used to compare a PBL teaching method and a traditional lecture-based method in two sections of a CS1 course taught by the same instructor. Each of the SDL components and grades were measured for students experiencing traditional instructional methods and problem-based learning methods. Readiness was measured with the Self-Directed Learning Readiness Scale, skills with the Motivated Strategies for Learning Questionnaire-Part B, performance with time spent on SDL tasks, and course motivation with the Motivated Strategies for Learning Questionnaire-Part A. The grade measurement was the course instructor's percentage score given to students' programming assignments. Results showed that the effect of teaching method was statistically significant for the SDL performance measure with the PBL section demonstrating greater performance. The effect of teaching method was not significant on SDL readiness, skills or course motivation measures. A lack of statistical differences between the two methods for these measures was attributed to no effect of PBL on students' SDL or small sample size resulting in reduced statistical power or lack of student engagement in PBL resulting in ineffective treatment. The effects of method, time, and method x time interaction were significant on the grades measure. The traditional teaching method group had higher grades than the PBL group. Both teaching methods exhibited declining grades over time. Factors such as increased difficulty of assignments and stricter grading schemes over time or differing characteristics of group members such as prior CS knowledge, age, time spent on assignments, and competing employment and other course demands were identified. Recommended future study includes improved measures of students' SDL practices rather than students' own perceptions, assessment of student practice of PBL, and qualitative study of students' motivation and SDL performance.