This paper describes a multi‐institutional study that used a repeated single‐criterion card sort to investigate graduating computer science students' knowledge of programming concepts. The study seeks to improve computer science instruction by gaining insight into how graduating students retain and assimilate introductory programming knowledge into their broader understanding of the discipline. A total of 291 card sorts was elicited from 65 undergraduate students in their final year of study at eight colleges and universities throughout the USA. To fully exploit the rich qualitative and quantitative aspects of the card sort data, an integrative analysis process was used that combined content analysis with two measures, normalized minimum spanning tree and edit distance, both developed specifically to analyze card sort data.