Background: Several different measures have been proposed to solve persistent validity problems, such as high task-sampling variability, in the assessment of students' expertise in 'doing science'. Such measures include working with a-priori progression models, using standardised item shells and rating manuals, augmenting the number of tasks per…

Background: Complexity models have provided a suitable framework in various domains to assess students' educational achievement. Complexity is often used as the analytical focus when regarding learning outcomes, i.e. when analyzing written tests or problem-centered interviews. Numerous studies reveal negative correlations between the complexity of…