The table "Weighted Student Participation Rates by School Type and Subject Area" shows the weighted student participation rates of eligible students. The set of eligible students consists of the selected students, after removing the excluded students. For a given session, a makeup session was called for when, for various reasons, more than a predetermined tolerable number of eligible students were absent from the originally scheduled session to which they were assigned. The participation rates given in the table express the number finally assessed as a percentage of those initially eligible in the participating schools. Participation rates are shown for public and private schools separately.
The combined impact of school nonparticipation and student absenteeism from sessions within participating schools is summarized in the table "Weighted Participation Rates by Subject Area, Grade, and Reporting Population." It shows the school participation rates before and after cooperating substitute schools are added and the student participation rates after absentee sessions are added. The two overall participation rates are the student participation rates multiplied to the before-substitution school participation rate and the after-substitution school participation rates respectively. The results show that, consistent with earlier rounds of NAEP, the overall level of participation decreases substantially with the increase in the grade of the students. Analysis is typically performed separately by grade and subject type, and NCES standards regarding acceptable potentials for bias are expressed in terms of weighted participation rates. The school and student participation rates decrease as grade increases for each subject, while participation rates by reporting population are essentially the same.
The procedures for substituting for nonparticipating schools or imputing for them through weighting and the procedures for imputing for absent students through weighting were designed to reduce the biases resulting from school and student nonparticipation.
|Subject area||Grade||Reporting population||School participation||Student participation||Overall participation|
|Before substitution||After substitution|
|SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2000.|