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Age Distribution Fractions


Age Distribution Fractions for Ages 9 and 13

Age Distribution Fractions for Age 17


Age distribution fractions are estimated proportions of students in each grade that are age-eligible. The fractions are components in the school measure of size. The computation of the age distribution fractions was done differently by age group. For ages 9 and 13, a breakout by every birth-year cohort represented in the relevant grades was fully carried out. The approach was simpler for the age 17 sample, using an age range between 16- and 17-years-old, because this age definition is based on an October-September birth cohort.

Last updated 17 March 2011 (GF)
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National Center for Education Statistics -
U.S. Department of Education