Problem-based learning (PBL) was originally introduced in medical education programs as a form of
small-group learning, but its use has now spread to large undergraduate classrooms in various other
disciplines. Introduction of new teaching techniques, including PBL-based methods, needs to be
justified by demonstrating the benefits of such techniques over classical teaching styles. Previously,
we demonstrated that introduction of tutor-less PBL in a large third-year biochemistry undergraduate
class increased student satisfaction and attendance. The current study assessed the generic problemsolving abilities of students from the same class at the beginning and end of the term, and compared
student scores with similar data obtained in three classes not using PBL. Two generic problemsolving tests of equal difficulty were administered such that students took different tests at the
beginning and the end of the term. Blinded marking showed a statistically significant 13% increase
in the test scores of the biochemistry students exposed to PBL, while no trend toward significant
change in scores was observed in any of the control groups not using PBL. Our study is among the
first to demonstrate that use of tutor-less PBL in a large classroom leads to statistically significant
improvement in generic problem-solving skills of students.