The National Assessment of Educational Progress (NAEP) currently tests seventeen-year-old students enrolled in public and private secondary schools, but it does not test "out-of-school" seventeen-year-olds who have either graduated or dropped out. Estimating that one of five seventeen-year-olds is out of school, the interpretability of NAEP findings is weakened by omitting those persons from assessment. This paper considers precision and sample size, as well as sampling strategies, for assessing out-of-school seventeen-year-olds. Four types of statistics (comparisons of average scores for states, average scores for population subgroups, comparisons across states of proportions of seventeen-year-olds performing at a given level, and proportions of subpopulations performing at a given level) are considered and illustrated with tables to indicate sample sizes necessary to attain alternative target levels of precision in the statistics. Two kinds of sampling strategies are described, one based on sampling households and other places of residence and the other on sampling at younger ages for recontact at age seventeeen. It is concluded that sampling out-of-school seventeen-year-olds will be best accomplished through cooperation with other ongoing survey efforts, such as the Current Population Survey of the Bureau of the Census and the National Educational Longitudinal Studies. (LMO)