This paper estimates the effects of state-imposed curriculum mandates on the test scores of public-school students who took the SAT in 2001. By 1998, 14 states had mandates that high-school students should take an economics course. For these states, the proportion of public-school students taking high-school economics was around twice that of states without mandates. The mandate may be interpreted as a regulation on input use in the education sector, potentially impairing the efficiency of schools. It is hypothesized that where there is a mandate, test scores should be lower. The merit of the mandate on scores can be assessed empirically. Using microlevel data on a large sample of students across the United States, this inquiry tests whether students' academic performances are higher or lower in states where there are mandates. This test offers a direct evaluation of the efficiency of the mandate. The mandate reduces test scores by as much as 0.25 standard deviations for those students who would not otherwise have enrolled. This paper sets out the theoretical explanation from the imposition of a mandate, describes the dataset, sets out the estimation method, and reports the results. (Contains 6 tables and 24 references.) (Author/WFA)