The Common Core of Data (CCD) public school file from which most of the sampled schools were drawn corresponds to the 2002-03 school year, some two years prior to the assessment school year. During the intervening period, some of these schools either closed, no longer offered the grade of interest, or were ineligible for other reasons. In such cases, the sampled school was coded as ineligible.
There are some jurisdictions with relatively high rates of ineligibility. Most of these occur in small states in which all schools are sampled, such as Delaware and Wyoming. These are of little concern since all schools were sampled and so the sampling error is not affected by the ineligible schools.
The one jurisdiction to note is the eighth-grade sample for Louisiana, where 20 percent of the schools were found to be ineligible. In Louisiana, ninth-grade students in high schools who had not completed the requirements for eighth grade were reported as eighth-graders to the CCD, although these students are actually taking ninth-grade classes. Thus, many high schools were sampled for the grade 8 assessment that were later found to be ineligible.