For each ASVAB subtest, the equation shown in Figure 6 was used to compute EAP ability estimates for applicants that completed the test during the 2009 fiscal year (FY2009; October 1, 2008 — September 30, 2009). The equation shown in Figure 5 was then used to compute PSDs (using the EAP ability estimates, and assuming a N(0,1) population distribution). The average of the squared PSDs was then computed over applicants, and substituted into the equation shown in Figure 4 to compute subtest reliability.
For AFQT scores, reliability was computed using the methodology for computing composite reliabilities reported in Gulliksen (1987; pg. 346-347, Equation 74).
Reliability estimates were computed over all FY2009 applicants, and by gender (Male, Female), ethnic group (Hispanic, Non-Hispanic), and race (American-Indian/Alaska Native, Asian, Black/African-American, Native Hawaiian/other Pacific Islander, White/Caucasian).
The sample sizes used to compute the reliability estimates across subtests and AFQT scores are given in the table below.