Does employer learning vary by schooling attainment? The answer depends on how career start dates are defined

• We find equal evidence of employer learning for high school and college graduates.
• This refutes a prior study that finds no employer learning for college graduates.
• We attribute the difference in findings to definitions of career start date.

We demonstrate that empirical evidence of employer learning is sensitive to how we define the career start date and, in turn, measure cumulative work experience. Arcidiacono et al. (2010) find evidence of employer learning for high school graduates but not for college graduates, and conclude that high levels of schooling reveal true productivity. We show that their choice of start date—based on nonenrollment at survey interview dates and often triggered by school vacations—systematically overstates experience and biases learning estimates toward zero for college-educated workers. Using career start dates tied to a more systematic definition of school exit, we find that employer learning is equally evident for high school and college graduates.