Introduction Students learn more effectively when they know what they do not know. Gaining insight into students’ metacognitive awareness is needed as misalignment between actual and self-perceived knowledge impedes their learning process. The optimal method of measuring self-perceived knowledge is still under debate. In this study, we evaluate the use of psychology-derived post-decision wagering for mapping students self-perceived knowledge.

Methods Students (n = 71) performed a pre-test on medical physiology, followed by a teacher-moderated discussion and a post-test with isomorph questions. Half of the students rated their self-perceived knowledge on each question using post-decision wagering, i. e. betting 1–5 points on the correctness of their answer, whereas the other half used a 5-point Likert scale to rate their confidence.

Results Self-perceived knowledge scores were higher for post-decision wagering (pre: 3.75 ± 0.14, post: 4.60 ± 0.07) compared with Likert scales (pre: 3.13 ± 0.08, post: 3.92 ± 0.08) despite similar actual knowledge scores. Furthermore, Likert ratings showed a near-normal distribution, whereas wagers were placed preferentially using the outer ends of the scale. Correlations between mean actual and self-perceived knowledge scores were low in both groups. On average, 8.5% of responses were classified as misconceptions, defined as highly confident incorrect answers.

Discussion Despite the presumed reliability of post-decision wagering, our findings suggest that we should adhere to the use of Likert scales as a balanced measure for self-perceived knowledge in medical education. Moreover, the prevalence of misconceptions did not alter after instruction, indicating a need for instructional