ABSTRACT
Objective: To compare knowledge retention of the two learning methods: online (OPBL) and in-class problem-based learning (IPBL). Methods: A pre and post-test study design of the three-week research project was performed in volunteered students from two-academic year. After completing the pretest, the IPBL group performed an activity test. Then the instructor held an open discussion for further explanation and clarification. Afterwards, students performed a diagnostic test to earn their achievement score. The 3-hour activities in each learning specification part took place exactly a week apart. The contrary, the OPBL group performed all tests by log on the website. The online program not only established their weaknesses and urged them to explore core knowledge, but also recorded students’ profiles. After three weeks, the post-test was arranged for both groups. Four week later, the final test was managed without prior notice. The pretest, post-test and final test forms were parallel under the same table of specifications. Results: The pretest, post-test and final test scores of the IPBL group and the OPBL group were 4.57 ± 2.92, 23.74 ± 7.58, and 12.70 ± 5.19; 4.94 ± 6.31, 31.67 ± 7.07, and 25.77 ± 5.9 respectively. The growths of knowledge after the post-test and after the final test as well as the retention of knowledge of the IPBL group and the OPBL group were 54.32%, 22.64%, and 68.32%; 76.01%, 59.63%, and 83.64% respectively. Conclusion: The OPBL yielded the better knowledge retention. The key success factors might depend on students’ achievement motive and a sense of self-actualization.