Cover-copy-compare is a self-management intervention strategy developed to improve students' academic performance, particularly in spelling. In academic intervention research, it is often assumed that students are completing the intervention as intended, yet this is seldom examined during intervention implementation or subsequent data analysis. The primary aim of this study was to retrospectively examine students' cover-copy-compare permanent products to assess their ability to adhere to the intervention and to examine whether intervention adherence influences intervention effectiveness. A secondary data analysis of 86 third-grade students participating in two randomized controlled trials examining the efficacy of cover-copy-compare on writing productivity was conducted. Results indicated that students' adherence to the cover-copy-compare intervention was high, and students' preintervention spelling performance and intervention adherence emerged as statistically significant predictors of students' postintervention spelling performance. Limitations of the study and implications for assessing students' intervention adherence are discussed.