NAEP Technical DocumentationStratification by Urbanicity Classification for the 2017 State Assessment

The creation of the urbanicity classification variable was based on the NCES urban-centric locale and was defined within each explicit stratum. The NCES urban-centric locale contains the following categories:

  1. Large City: Territory inside an urbanized area and inside a principal city with population of 250,000 or more;
  2. Mid-size City: Territory inside an urbanized area and inside a principal city with population less than 250,000 and greater than or equal to 100,000;
  3. Small City: Territory inside an urbanized area and inside a principal city with population less than 100,000;
  4. Large Suburb: Territory outside a principal city and inside an urbanized area with population of 250,000 or more;
  5. Mid-size Suburb: Territory outside a principal city and inside an urbanized area with population less than 250,000 and greater than or equal to 100,000;
  6. Small Suburb: Territory outside a principal city and inside an urbanized area with population less than 100,000;
  7. Fringe Town: Territory inside an urban cluster that is less than or equal to 10 miles from an urbanized area;
  8. Distant Town: Territory inside an urban cluster that is more than 10 miles and less than or equal to 35 miles from an urbanized area;
  9. Remote Town: Territory inside an urban cluster that is more than 35 miles from an urbanized area;
  10. Fringe Rural: Census-defined rural territory that is less than or equal to 5 miles from an urbanized area, as well as rural territory that is less than or equal to 2.5 miles from an urban cluster;
  11. Distant Rural: Census-defined rural territory that is more than 5 miles but less than or equal to 25 miles from an urbanized area, as well as rural territory that is more than 2.5 miles but less than or equal to 10 miles from an urban cluster;
  12. Remote Rural: Census-defined rural territory that is more than 25 miles from an urbanized area and is also more than 10 miles from an urban cluster.

In addition to the 12 categories, the category "outside of the United States" is used, referring to Department of Defense Education Activity (DoDEA) overseas schools or Puerto Rico. For the definitions of the geographic terms used in these descriptions, please refer to the Census Bureau’s website (for example, www.census.gov/programs-surveys/metro-micro.html)

The urbanicity classification cells were created by starting with the original NCES urban-centric locale categories. Urbanicity strata were collapsed with neighboring strata until a minimum cell size criterion, in terms of the percentage of students, was met. The minimum cell size criterion varied by type of explicit stratum. The criterion for explicit strata comprising the largest TUDA districts (Los Angeles, New York City, Chicago, Miami-Dade, Houston and Clark County) was 12 percent; for the other TUDA districts, it was 18 percent; and for all other explicit strata, it was 9 percent.

The urbanicity classification variable was equal to the original NCES urban-centric locale if no collapsing was necessary. If collapsing was necessary, the collapsing scheme first collapsed within the four major strata (city, suburbs, town, rural). For example, urbanicity categories 1, 2, and 3 within city were collapsed (1 with 2, 2 with 3) if cells 1 or 3 were deficient. If the middle cell (e.g., 2) was deficient, then it was collapsed with the smaller of the two end cells. If a collapsed pair was still deficient, it was collapsed with the remaining unit within the major stratum. That is, a single city cell would be created by collapsing the large city, mid-size city, and small city cells. If a cell was still deficient after collapsing within major stratum, further collapsing across major strata occurred as needed until the deficiency was resolved. The values of the urbanicity classification variable were set equal to the cell value of the final level of collapsing.

Prior experience with this type of stratification has shown that the greatest efficiency of stratification results when cities and suburb fringe areas are always kept separate from towns and rural areas, even if the enrollment criterion is violated.

Last updated 01 April 2022 (SK)