<p>Analyzing their mistakes affords students opportunities for improved learning and success in problem solving disciplines, especially when students are able to identify reasons for their errors and modify their future study behavior. To help students make appropriate adjustments, instructors must understand the language students use to describe their own academic performance. This study explores what students mean when they say they made “simple mistakes.” Eight students participated in interviews where they reviewed errors from a recent exam, explaining why errors were simple or not simple. We analyzed the interview data using Causal Attribution Theory and discovered how students’ attributions of their errors influence their classification of their errors as simple or not simple. Results include descriptions of simple and not simple distinctions for three categories of students and evidence of similarities among students within each category regarding their self-efficacy and persistence through struggle. The analysis also reveals how students plan to adjust their study approach based on their classification of their errors. Across categories, students believe simple mistakes are preventable through repetitive practice or memorization, while not simple mistakes require help seeking, but students within different categories differ in how they use these strategies. The results show that that different students can use the same language to convey very different meanings for their own error categorizations and that there is need for instructors to probe these meanings before providing guidance. Our results also provide support for previous calls for interventions aimed at retraining students’ causal attribution styles towards controllable, unstable causes.</p>