NAEP Technical DocumentationSchool Base Weights for the 2017 Assessment

The school base weight for a sampled school is equal to the inverse of its overall probability of selection. The overall selection probability of a sampled school differs by

• type of sampled school (original or substitute);
• sampling frame (new school frame or not).

The overall selection probability of an originally selected school in a mathematics, reading, or writing sample is equal to its probability of selection from the NAEP public/private school frame.

The overall selection probability of a school from the new school frame in a mathematics, reading, or writing sample is the product of two quantities:

• the probability of selection of the school's district into the new-school district sample or the Catholic diocese into the new-school Catholic diocese sample, and  
• the probability of selection of the school into the new school sample.

The new-school district sampling procedure for the 2017 national public school writing assessment is very similar to the new-school district sampling procedures for the 2017 state public schools assessment in mathematics and reading. New-school Catholic diocese sampling procedures for the 2017 national private school assessment for mathematics and reading and for writing are similar as well.

Substitute schools are preassigned to original schools and take the place of original schools if they refuse to participate. For weighting purposes, substitute schools are treated as if they were the original schools that they replaced, so substitute schools are assigned the school base weight of their corresponding original schools.

Learn more about substitute schools for the 2017 private school national assessment in mathematics and reading and substitute schools for the 2017 private school national assessment in writing.

Printer-friendly Version