STEM educators have devoted increasing attention to discrete mathematics in recent years due, in part, to its strong connections with subjects like computer science, probability and statistics, and business management. Combinatorics problems, in particular, while useful for modeling concrete situations, are often considered to be tricky for students. To develop a better understanding of students' conceptions regarding problems involving permutations and combinations, a secondary data analysis using a grounded theory approach was performed on transcripts of student interviews obtained during an earlier study. Participants had recently completed a college-level discrete mathematics course with a passing grade. Analysis focused on answering two research questions: 1) What patterns of responses do students generate while producing solutions to combinatorics word problems? 2) What underlying conceptual ideas lead to these patterns?