The U.S. Environmental Protection Agency (EPA) reregistered Bt corn in 2001 with mandatory Insect Resistance Management (IRM) requirements in order to promote sustainable use by farmers. Since then studies report IRM compliance rates ranging from 80 to 90 percent. Using survey data from Minnesota and Wisconsin, we show that previous compliance rate estimates are likely too high because they do not use a comprehensive measure for compliance. With a more comprehensive measure, we find compliance rates ranging between 60 to 75 percent.