Many studies in mathematics education research occur with a nonrepresentative sample and are never replicated. To challenge this paradigm, I designed a large-scale study evaluating student conceptions in group theory that surveyed a national, representative sample of students. By replicating questions previously used to build theory around student understanding of subgroups, cyclic groups, and isomorphism with over 800 students, I establish the utility of replication studies to (a) validate previous results, (b) establish the prevalence of various student conceptions, and (c) reexamine theoretical propositions. Data analyzed include 1 round of open-ended surveys, 2 rounds of closed-form surveys, and 30 follow-up interviews. I illustrate the potential of replication studies to refine theory and theoretical propositions in 3 ways: by offering alternate interpretations of student responses, by challenging previous pedagogical implications, and by reevaluating connections between theories.