The survey was used to gain insight into student performance before the interviews. Three reactions were analyzed, which required differing use of resources. The z-scores for two population proportions were calculated to compare student success on each problem within the spring and summer cohorts. The proportion of correct responses for the Zaitsev elimination was statistically higher using a 95% level of confidence in both the spring and 290 summer cohorts. There was no statistical difference between the Markovnikov and Hofmann proportion correct for either cohort. The association between the extent of substitution and stability is a heuristic introduced for students to gauge the reactivity and stability of alkenes.