More and more students attend private supplementary tutoring to improve their academic achievement. Private tutoring might be understood as a reaction to insufficient instructional quality in school, especially regarding individual support. However, it might also be possible that parents generally see insufficient grades as an indicator of lacking…

An impediment to conducting high-quality quantitative research studies in education is the paucity of valid measures of learning gains. Studies often seek to investigate students' deep, conceptual understanding yet many measures assess only surface, procedural understanding. One reason is that the development of validated measures of conceptual…