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Rehab Measures: Differential Aptitude Test

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Title of Assessment

Differential Aptitude Test 



Instrument Reviewer(s)

Initially reviewed by Timothy P. Janikowski, PhD and his University at Buffalo Rehabilitation Counseling Master’s students, Janel Anthony & Anthony Yammarino (4/10/2015)

Summary Date



The Differential Aptitude Tests (DAT) is a multiple aptitude test battery designed to measure Grades 7-12 students' and some adults' ability to learn or to succeed in selected areas. 


  • The DAT first published in 1947 and has multiple forms and levels. The DAT contains eight scales: Verbal Reasoning (VR), Numerical Ability(NA), Abstract Reasoning (AR), Perceptual (Clerical) Speed and Accuracy (PSA), Mechanical Reasoning (MR), Space Relations (SR), Spelling (Sp). and Language Usage (LU). Nine scores are provided, one for each scale and a composite score from VR and NR--the Scholastic Aptitude score (SA)
  • All the tests except PSA are multiple-choice. In MR, problems are presented using drawings. Users may choose to score the tests by hand, by scanner, or to have them scored by The Psychological Corporation.
  • Maximum and minimum standard scores not established in research, but reported in DAT manual
  • The DAT is linked to the Career Interest Inventory to assist with vocational counseling and planning.

Area of Assessment

Attention and Working Memory; Cognition; Executive Function; Language; Processing Speed; Reading Comprehension; Reasoning and Problem Solving 

Body Part

Not Applicable 

ICF Domain

Activity; Participation 



Assessment Type

Performance Measure 

Length of Test

60 Minutes or More 

Time to Administer

Subtest times vary from 12-25 minutes, up to 3 hours required to administer all parts.

Number of Items

Varies by Subtest & Form 

Equipment Required

Paper & Pencil for Standard Administration
Computer, Keyboard, & Mouse for Computerized Administration

Training Required

Level B credentials required. Training in test administration and scoring is required.

Type of training required

Reading an Article/Manual; Training Course 


Not Free 

Actual Cost

$20 per test for booklet, answer document, directions, and practice test materials; $20 for norms booklet; $20 for technical manual; $1.50 for scoring each answer document

Age Range

Child: 6-12 years; Adolescent: 13-17 years 

Administration Mode




Populations Tested

● Students Grades 7-12
● Entry level college students

Standard Error of Measurement (SEM)

First Year Secondary School Students (Evers & Mur, 2000)

All SEM values were calculated used Standard Deviations & ICC from the above citation:

  • SP: SEM= +/- (4.57 - 4.13)
  • LU: SEM= +/- (3.53 - 3.19)
  • VR: SEM= +/- (3.53 - 3.19)
  • AR: SEM= +/- (3.34- 2.56)
  • SR: SEM= +/- (4.08 - 3.13)
  • MR: SEM= +/- (3.79- 2.91)
  • NA: SEM= +/- (2.72- 2.09)
  • PSA: SEM= +/- (3.09- 2.37)

Minimal Detectable Change (MDC)

Not Established

Minimally Clinically Important Difference (MCID)

Not Established

Cut-Off Scores

Not Established

Normative Data

The 5th edition of the DAT was normed on a sample of 84,000 students in grades 7 to 12.        

First Year Secondary School Students (Evers & Mur, 2000)

  • SP: Mean= 55.6 (8.8)
  • LU: Mean= 25.3 (6.8)
  • VR: Mean= 16.1 (6.8)
  • AR: Mean= 31.5 (8.1)
  • SR: Mean= 29.1 (9.9)
  • MR: Mean= 36.7 (9.2)
  • NA: Mean= 16.8 (6.6)
  • PSA: Mean= 28.2 (7.5)

Boys & Girls in UK Secondary Schools (Lynn, 1992)

Means are available for males and females for all DAT subsets.

13-14 year olds:

  • Males: Mean= 13.6 to 54.8
  • Female: Mean= 12.0 to 56.3

14-15 year olds:

  • Male: Mean= 15.8-57.9
  • Female: Mean= 14.4 to 62

15-16 year olds:

      Male: Mean= 18.1 to 63.1

      Female: Mean= 16.3 to 67.9

 16-17 year olds:

      Male: Mean= 26.9 to 76.1

      Female: Mean= 22.9 to 78.8

17-18 year olds:

      Male: Mean= 30.2 to 81.4

      Female: Mean= 25.8 to 86.0

The test reports results in percentile rankings based on age and gender and Stanines with a mean of 5 and SD of 2

Test-retest Reliability

Unknown Population (French & Beaumont, 1991)

  • Language Usage Test: Excellent (ICC = 0.89)
  • Spelling Test: Excellent (ICC = 0.91)

Interrater/Intrarater Reliability

Not Established

Internal Consistency

(Evers et al., 2000)

  • Excellent for AR, SR, MR, NA, PSA, subscales: Cronbach’s alphas= 0.83 - 0.90
  • Adequate for SP, LU, VR subscales: Cronbach’s alphas= 0.73 - 0.78

(Wang, 1993)

  • Excellent internal consistency coefficients computed with the K-R 20 formula (For all DAT subsets r varied from 0.82-0.95)

(Alkhadher, et al. 1998)

  • Excellent internal consistency computed with the KR20 for both computerized and pencil forms (males – r varied for all DAT subsets from 0.85-0.94) and (females – r varied for all DAT subsets from 0.79-0.94)
  • Excellent split-half reliability coefficients for males and females, respectively (For all DAT subsets r varied from 0.89-0.95)

Criterion Validity (Predictive/Concurrent)

Predictive Validity

(Layton & Swanson, 1958)

  • Excellent predictive validity for VR and NA at 9th grade level when correlated to future performance on 11th grade American Council on Education Psychological Examination, Cooperative English Test, and high school rank (males – r= 0.63-0.69; females - r= 0.61-0.71)

(Gray, 1965)

  • Excellent predictive validity for VR when correlated to Military Academic Class Standing (For all DAT subsets r= 0.69-0.78)
  • Excellent to Adequate predictive validity for AR when correlated to Military Academic Class Standing (For all DAT subsets r= 0.51 - 0.68)
  • Adequate predictive validity for LU (Sentences) when correlated to Military Academic Class Standing (For all DAT subsets r= 0.41 - 0.52)

(Alkhadher, et al. 1998)

  • Adequate predictive validity for the NA test, in both computerized and pencil formats, when correlated with all the training courses and with the overall evaluation (For all DAT subsets r= 0.36-0.40)

(Berdie, 1951)

  • Adequate predictive validity for NA test when correlated to first year mathematics scores at the University of Minnesota Institute of Technology (r= 0.45)
  • Adequate predictive validity for SR test when correlated to first year drawing scores at University of Minnesota Institute of Technology (r= 0.38)
  • Poor predictive validity for the AR test when correlated with overall evaluation and with all training courses (For all DAT subsets r= 0.19-0.21)
  • Poor to Adequate predictive validity for the MR test when correlated with overall evaluation (For all DAT subsets r= 0.26-.031)

Concurrent Validity:

(Wolking, 1955)

  • Excellent concurrent validity on VR test when correlated to verbal scores on Test of Primary Mental Abilities (PMA) (r= 0.74)
  • Excellent concurrent validity on NA test when correlated to numerical scores on PMA (r= 0.63)
  • Adequate concurrent validity on SR test when correlated to spatial scores on PMA (r= 0.47)

Construct Validity (Convergent/Discriminant)

Convergent Validity:

(Doppelt & Wesman, 1952)

  • Excellent convergent validity for VR when correlated to Tests of Educational Development (TED) General Vocabulary scores (For all DAT subsets r= 0.69-0.88)
  • Excellent convergent validity for NA when correlated to TED Quantitative thinking scores (r= 0.80)
  • Adequate to Excellent convergent validity for LU (Sentences) when correlated to TED Correctness and Appropriateness of Expression scores (For all DAT subsets r= 0.57-0.89)

Content Validity

Not statistically assessed, however after thorough review and revising the test content was deemed to be appropriate considering the purposes of the DAT (Wang, 1993)

Face Validity

Not statistically assessed, but the items for each subtest appear to represent the corresponding aptitude being measured (Gray, 1965)

Floor/Ceiling Effects

Not Established


Not Established

Professional Association Recommendations



  • The DAT can be effective in a vocational assessment, determining what specialized areas one might focus in on for employment. (Layton & Swanson, 1958)
  • The DAT loses its ability to differentiate between individuals in higher education and advanced students.
  • The DAT is used in numerous international studies and has yielded results similar to the American version of the test.
  • Based upon the research articles, the DAT is a reliable and valid testing measure, however the time period of each article should be taken into consideration for future application of the DAT.


Alkhadher, O., Clarke, D. D., & Anderson, N. (1998). Equivalence and predictive validity of paper-and-pencil and computerized adaptive formats of the Differential Aptitude Tests. Journal Of Occupational And Organizational Psychology, 71(3), 205-217. doi:10.1111/j.2044-8325.1998.tb00673.x

Berdie, R. F. (1951). The Differential Aptitude Tests as predictors in engineering training. Journal of Educational Psychology, 42(2), 114-123. doi: 10.1037/h0060648

Doppelt, J. E., & Wesman, A. G. (1952). The Differential Aptitude Tests as predictors of achievement test scores. Journal Of Educational Psychology, 43(4), 210-217. doi:10.1037/h0060030

Evers, A., Nijenhuis, J. T., & Mur, J. P. (2000). Validity of the differential aptitude test for the assessment of immigrant children. Educational Psychology, 20(1), 99-115. doi:10.1080/014434100110416

French, C. C., & Beaumont, J. G. (1991). The Differential Aptitude Test (Language Usage and Spelling): A clinical study of a computerized form. Current Psychology: A Journal for Diverse Perspectives on Diverse Psychological Issues, 10(1-2), 31-48. doi: 10.1007/BF02686779

Gray, B. (1965). The differential aptitude tests in a military academic setting. The Journal of Educational Research, 58(8), 352-354. doi:10.1080/00220671.1965.10883242

Layton, W. L., & Swanson, E. O. (1958). Relationship of ninth grade Differential Aptitude Test scores to eleventh grade test scores and high school rank. Journal Of Educational Psychology, 49(3), 153-155. doi:10.1037/h0046365

Lynn, R. (1992). Sex differences on the Differential Aptitude Test in British and American adolescents. Educational Psychology, 12(2), 101-106.

Wang, L. (1993). The Differential Aptitude Test: A Review and Critique.


Wolking, W. D. (1955). Predicting academic achievement with the Differential Aptitude and the Primary Mental Ability Tests. Journal Of Applied Psychology, 39(2), 115-118. doi:10.1037/h0039856

Year published

Original Publication Date: 1947 

Instrument in PDF Format

Approval Status Approved 
Created at 9/3/2015 10:14 AM  by Jason Raad 
Last modified at 5/17/2016 3:35 PM  by Jason Raad