Validation of a short questionnaire to assess the degree of complexity and structuredness of PBL problems.

Background: In problem-based learning (PBL), problems represent the starting point of students' learning activities. Therefore, the quality of these problems should be high, in that they should be of an adequate level of complexity and structuredness. Previous research has proposed several guidelines for constructing problems, but some of them are rather vague and are not based on empirical evidence.