Validity of NAT Study

Monday, June 13, 2011, 8:11
NTS, Test Prep
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Validity of NAT Study By:

Dr. Douglas Trimble, Director of Assessment and Institutional Research
Forman Christian College University.

Comparing the NAT to the SAT (in the USA), we see that it fares very well at Forman Christian College: it correlates .36 with first year GPA (FYGPA), which is the same as the SAT (.35). Despite the lack of systematic predictive validity analysis of the NAT, it does appear to have good predictive validity. Because SAT and high school GPA correlate only .28, Korbin, Patterson, Shaw, Mattern, and Barbuti (2008) concluded that they appear to be measuring distinct aspects of academic promise and both can yield valuable information. The same appears to be the case with the NAT, which only correlates .27 with the composite BISE total; thus BISE and NAT are helpful.

USA 2006-2007 N = 151,316		FC College 2008-2009 N = 495-574 for BISE and 52-64 for A Level
SAT & High School GPA	0.28	NAT & BISE Composite	0.27
SAT & High School GPA & FYGPA	0.46	(NAT + BISE Composite) & FYGPA (NAT + A Level) & FYGPA	0.49 0.48
SAT & FYGPA High School GPA & FYGPA	0.35 0.36	NAT & FYGPA BISE Composite & FYGPA A Level & FYGPA	0.36 0.46 0.37

Note:FYGPA is the first year grade point average after two semesters of university work. SAT is the combined Critical Reading, Mathematics, and Writing sections. The NAT was combined statistically with the BISE exams or A Level exam by converting them z-scores. Data from the USA was reported in Korbin, J. L., Patterson, B. F., Shaw, E. J., Mattern, K. D., & Barbuti, S. M. (2008). Validity of the SAT for predicting first-year college grade point average (Research Report No. 2008-5). New York: College Board. Retrieved May 21, 2009 from
” Validity of SAT Test ” (PDF)

The predictive power of using the Composite BISE to predict FYGPA (r = .46) is similar to the SAT and high school GPA (.46) to predict FYGPA. By adding the NAT and BISE Composite together to predict FYGPA, then the correlation increases to .49. The NAT likewise increases our FYGPA predictive precision when it is combined with the A Level exam results from .37 to .48. We have therefore decided to use an equally weighted combination of NAT and BISE score (or A Level marks) to make admissions decisions.