From a self-regulated learning perspective, adequate monitoring of own learning processes and outcomes is crucial to regulate one's own learning effectively. Research on metacognitive judgments, however, clearly indicates that students frequently overestimate their actual performance. Therefore, the present study with N = 209 undergraduate students aimed to support students in developing accurate judgments in order to improve learning processes and, eventually, performance. A quasi-experimental design with three conditions (metacognitive training, testing, and control) and five testing sessions was implemented. In addition to repeated testing plus individual feedback in the testing group, students in the metacognitive training group received psychoeducation, made item-specific judgments, and were given feedback. Over and above the positive effects of repeated testing, metacognitive training positively influenced several monitoring accuracy scores (bias, absolute accuracy, and specificity) and students' performance. Moreover, the metacognitive training group exhibited a nonlinear interindividual decrease in overconfidence. Overall, the study provided considerable evidence that monitoring accuracy and performance can be improved by means of judgment training.
