High school sizes vary by location. In urban areas almost half of all high schools are large (900 or more students), whereas in rural areas half of all high schools are very small (fewer than 300 students).

Large high schools have traditionally been considered more economical and able to support a broader curriculum than smaller ones (Lee et al. 2000). In recent years, however, research has suggested that small and moderate size high schools foster more positive social and academic environments than large high schools, especially for economically disadvantaged students (Lee and Bryk 1988, 1989; Bickel et al. 2001). This research also suggests that students in very small high schools learn less than students in "moderate" size (600–899 students) high schools (Lee and Smith 1997). This indicator profiles the distribution of high schools by size and selected characteristics.

During the 1999–2000 school year, high schools were not evenly distributed by size. Those in central cities or in urban fringe/large towns were more likely than those in rural areas/small towns to be large (i.e., to have 900 or more students), while those in rural areas/small towns were more likely than those elsewhere to be very small (to have fewer than 300 students). High schools with the highest percentages of limited English proficiency (LEP) enrollments were more likely than those with the lower percentages to be large, while those with the lowest percentages of LEP enrollments were more likely than all others to be very small. Among public high schools, those with the highest percentages of students receiving free or reduced-price lunches were more likely than those with lower percentages to be very small (see table 30-1).

Among regular high schools, a positive relationship exists between school size and the percentage of teachers who reported that apathy, tardiness, absenteeism, dropping out, and drug use are "serious" problems among students in their school. Teachers in larger schools were generally more likely to report that these problems are serious than were their peers in relatively smaller schools. When examined across locations, this pattern generally held true in central cities and rural areas/small towns, but not in urban fringe/large towns (see table 30-2).