Administration of the CAT-ASVAB

Administration of the CAT-ASVAB

Created Variables

ASVAB_GS_ABILITY_EST_POS. One example of the variables that provide final ability estimates summarizing the respondent's performance on each subtest (in this case, GS stands for the General Science subtest). Available for 12 subtests. Several different types of ASVAB scores were created. The data includes final ability estimates that summarize the respondent's performance on each subtest. Because computer-adaptive testing means that respondents do not answer the same questions, their raw scores cannot be directly compared. To provide a score that can be compared across respondents, DOD created the final ability estimates using Item Response Theory (IRT). These scores are computed on a comparable scale and thus, can be compared across respondents--that is, a lower score indicates poorer performance, and a higher score indicates better performance. 

ASVAB_MATH_VERBAL_SCORE_PCT. Provides a summary percentile score variable created by NLS staff for four key subtests. This variable is similar to the AFQT score that is familiar to experienced NLSY79 users. Created by first grouping respondents into three-month age groups: the oldest cohort included those born from January through March of 1980, while the youngest were born from October through December 1984. Custom sampling weights were computed for the sample of 7,093 respondents who have scores on all four exams and were assigned for each respondent's scores. Within each three-month age group and using the sampling weights, NLS staff assigned percentiles for the theta scores for the tests on Mathematical Knowledge (MK), Arithmetic Reasoning (AR), Word Knowledge (WK), and Paragraph Comprehension (PC) based on the weighted number of respondents scoring below each score.  Percentile scores for WK and PC were added to get an aggregate Verbal score (V) for which an aggregated intra-group, internally normed percentile was then computed.  The percentile scores for MK, AR and two times the aggregated percentile for V were then summed. Finally, within each group NLS staff computed a percentile score, using the weights, on this aggregate score, yielding a final value between zero and 99. Although the formula is similar to the AFQT score generated by the Department of Defense for the NLSY79 cohort, this variable reflects work done by NLS program staff and is neither generated nor endorsed by the Department of Defense. More information about the statistical methods used to create both the IRT subtest scores and ASVAB_MATH_VERBAL_SCORE_PCT is provided in Appendix 10 in the NLSY97 Codebook Supplement.


Important Information About Using ASVAB Data

Respondents who did not take the ASVAB are assigned a -4, valid skip, in the data. For most NLSY97 variables, a valid skip indicates that the respondent was not supposed to be asked a particular question. However, all respondents were eligible for the ASVAB administration, and a valid skip for these variables means that the respondent chose not to participate.

From the summer of 1997 through the spring of 1998, most NLSY97 round 1 respondents participated in the administration of the computer-adaptive form of the Armed Services Vocational Aptitude Battery (CAT-ASVAB). In this study, also called the Profile of American Youth 1997, the Department of Defense (DOD) used the NLSY97 sample as part of a larger effort to establish new norms for the CAT-ASVAB, a military enlistment test. 

The Armed Services Vocational Aptitude Battery measures the respondent's knowledge and skills in the topical areas listed in Figure 1. The flexibility of the computer-adaptive version allows the test program to route youths through each topical series of questions according to their responses. If a respondent answers a question correctly, the next question will be more difficult; if the respondent answers the question incorrectly, his or her next question will be comparatively easier.  The CAT-ASVAB also permitted the administration of an "easy" form of the test to the youngest NLSY97 youths, those born in 1983 and 1984.  In the easy form, the first question in each section is easier than the standard form.

Figure 1. Contents of the CAT-ASVAB

Arithmetic reasoning Electronics information Numerical operations
Assembling objects General science Paragraph comprehension
Auto information Mathematics knowledge Shop information
Coding speed Mechanical comprehension Word knowledge

In addition to scores on the tests, ASVAB data available in the current data set include the following sets of variables:

  • The number of items answered in each section.
  • An estimate of the precision of the ability scores (not included for coding speed and numerical operations).
  • Answers to the "online questionnaire," which respondents answered during the ASVAB administration. The questions collected information on the respondents' school experience, family background, reasons for taking the ASVAB, and perceptions of the test-taking environment.
  • Question timings for each of the items in the online questionnaire.

These variables can be found by searching by question name in NLS Investigator for the prefix "ASVAB_".

Sample Definition and Testing Procedures

During the NLSY97 screening process, two additional nationally representative samples were identified to complete the CAT-ASVAB. The first group, the Student Testing Program (STP), consisted of students, screened during the spring and summer of 1997, who expected to be in the 10th through 12th grades in the fall of 1997. Included were many respondents who also participated in the main NLSY97 survey, as well as youths who refused to participate in or were not eligible for the NLSY97.

The second sample, the Enlistment Testing Program (ETP), was a nationally representative sample of youths 18 to 23 years old as of June 1, 1997. This group provided the normative information that will be used by the Department of Defense to determine the score distribution of military-eligible youths and will help to assess the impact of these tests on minority and female military eligibility. The sample for this group, none of whom were eligible for the NLSY97, was drawn during the same screening period. 

The administration of the CAT-ASVAB was conducted by NORC representatives according to standard ASVAB procedure guidelines; respondents were paid $75 for their participation. Groups of five to ten persons were tested under standardized conditions at more than 280 test sites throughout the United States. Many respondents took the CAT-ASVAB at Sylvan Learning Centers; others were administered the test at temporary sites including hotels, community centers, and libraries. A total of 7,127 NLSY97 respondents (or 79.3 percent of the NLSY97 sample) completed this test:  5,452, or 80.8 percent, of the cross-sectional sample and 1,675, or 74.9 percent, of the supplemental sample.

Comparison to Other NLS Surveys: The ASVAB, in paper-and-pencil form, was administered to NLSY79 respondents in 1980. Scores are available for 93.9 percent of that cohort's members.  For more information, consult the NLSY79 User's Guide.

Related User's Guide Sections College Experience
School Experience
School & Transcript Surveys
Main Area of Interest Education: Achievement Tests
Supplemental Areas of Interest Education: College Experience
Education: School Experience