Norms provide a summary of test performance for a group of examinees. The group (referred to here as the reference group) is typically a large sample of examinees that is representative of the examinee population of interest. Norms are developed using the reference group, and then applied to the scores of individual examinees to summarize their performance relative to the performance of the reference group.

National norms are norms that are developed using a nationally representative sample of examinees that are at the age or educational level for which the test is developed. National norms provide a basis for evaluating performance for all examinees nationwide. National norms are created by conducting national norming studies. Because national norming studies are a difficult undertaking, they tend to be conducted fairly infrequently.

National norming studies for the ASVAB Testing Program are typically conducted every 15-20 years. The current national norms for the ASVAB were implemented in 2004. A nationally representative sample consisting of about 6,000 American youths aged 18-23 was utilized in the creation of the norms. These youths were identified from a screening of over 90,000 housing units, as part of the Profile of American Youth 1997 (PAY97) study. In the summer and fall of 1997, the CAT-ASVAB was administered to study participants under standardized conditions. The performance of this reference group was then used to develop new norms for the ASVAB.