Estimation of student's programming expertise

Context: Despite the fact, that the various automated expertise metrics were proposed, we do not know which metrics the most reliably capture/reflect expertise. Goal: To define metrics for estimation of developer's expertise based on programming tasks, to evaluate which of them most reliably capture expertise, and to propose and evaluate an automatic process to compare the metrics. Method: We define three expertise metrics with respects to such characteristics as spent time, performed activities and complexity of source code. We evaluate Spearman's correlation between our expertise metrics and students' score obtained after completion of a programming course with 251 students. Results: The best (very strong) correlation is between the metrics based on complexity of source code and the student's qualification points. Conclusions: Very strong but not perfect correlation is between our estimation of student's expertise and his/her score in the second third of the course. Approximately in the middle of the course we might be able to predict students' grades.