Identifying student difficulties with basic data structures

To be effective instructors and CS education researchers, we must identify and understand student difficulties surrounding core computing topics. This study examines student difficulties with the basic data structures commonly found in CS2 courses. Initial exploration of student thinking began with think-aloud interviews with students. These interviews centered on open-ended questions that were iteratively improved upon based on analysis of interview transcripts. The revised open-ended questions were then posed to 249 students during an end-of-term final exam study session. Using the explanations and justifications included by students, responses to the questions were coded and summarized. This work characterizes the difficulties revealed by student responses, and provides details of their prevalence among the examined student population.