Those black or white streaks, spots, and comets zipping across the screen. We count as dropouts any loss of playback signal that is 20 decibels or more below the nominal playback level (16 decibels for extra high-grade and 8mm tapes) and lasting for 15 microseconds or longer (about one quarter of one horizontal scan on the TV screen).
Calculated two ways: (1) Number of students who were enrolled in the 8th grade but were not enrolled in the 12th grade 4 years later. Enrollment is based on average daily attendance for the school year; (2) 8th to graduation. The 1st calculation provides breakout of race and gender data; second is available only for all students.
Students in grades 7-12 who leave school before graduation and do not transfer to another school are considered dropouts. Dropout information is reported for any school with a grade 7 or higher.