The oldest and most venerable of the tests of specific cognitive abilities

Donald D. Hammill, Ronnie L. McGhee, David J. Ehrler

• Ages: 6-0 through 17-11
• Testing Time: 40 minutes–2 hours
• Administration: Individual
• Scoring: Paper record forms

12 subtests on the DTLA-5:

• Humanities/Social Studies
  
• Science/Mathematics
  
• Word Opposites
• Word Associations
• Geometric Matrices
• Geometric Sequences
• Sentence Imitation
• Word Span
• Design Reproduction
• Reversed Letters
• Trail Making
• Rapid Naming

Results can be combined to form 9 composites

• Cognitive Subdomains:

• Acquired Knowledge
• Verbal Comprehension
• Nonverbal Problem Solving
• Verbal Memory
• Nonverbal Memory
• Processing Speed

• Reasoning Ability
• Processing Ability
• General Cognitive Ability

Validity

DTLA-5 was normed with a large normative group of 1,383 students across the United States.  The normative sample was representative of the 2015 U.S. population in a number of cultural and regional characteristics.  Scoring is based on age levels.  Numerous steps were taken to detect and eliminate sources of cultural, gender, and racial bias. First, the effects of bias were controlled and minimized through the inclusion of minority and disability groups in the normative sample. Second, the examination of reliability and validity information was presented for all these subgroups. A particularly powerful element of content-description validity is the demonstration of excellent internal consistency reliability for the different racial, ethnic, and gender groups. Third, extensive studies of test bias (both differential item functioning and subgroup comparison studies) were conducted, indicating the DTLA-5 possesses little or no bias in regard to gender, race, or ethnicity.

Evidence of the validity of DTLA-5 test scores is provided for content-description validity, criterion-prediction validity, and construct-identification validity. Content-description validity is demonstrated through careful documentation of subtest and item selection and analysis. A particularly powerful method for content-description validity is the use of conventional item analysis procedures, which allow the identification of good items and the deletion of bad items.

Construct-identification validity is demonstrated by including studies of age differences, subgroup performance, relationship to achievement, and confirmatory factor analysis of the test’s structure. These studies indicated that the DTLA-5’s internal structure is sound and its results are valid for a wide variety of subgroups, as well as for a general population. Criterion validity was confirmed by comparing the DTLA-5 with other notable assessments.

Reliability 

Reliability of the DTLA-5 was investigated using estimates of content sampling and time sampling. Internal consistency reliability coefficients (content sampling) range from .79 to .90 for the subtests, from .87 to .95 for the subdomain composites, and from .95 to .98 for the domain and global composites. Time sampling was investigated using the test–retest technique. Test–retest coefficients range from .72 to .90 for the subtests, from .80 to .92 for the subdomain composites, and from .93 to .96 for the domain and global composites.

Normative Scores 

The DTLA-5 Online Scoring and Report System (provided as part of the DTLA-5 Complete Kit) was designed as a quick, efficient tool for (a) entering test-session data; (b) converting subtest item scores or subtest total raw scores into scaled scores; (c) converting sums of scaled scores into composite index scores, percentile ranks, and upper and lower confidence intervals; (d) comparing DTLA-5 scores to identify significant intraindividual differences; and (e) obtaining a score summary and narrative report.  Scoring was found to be very sensitive to small differences, across ability levels.

The DTLA-5 Online Scoring and Report System yields four types of normative scores: age equivalents, percentile ranks, subtest scaled scores, and composite indexes. Percentiles provide the examiner with an index that is easily understood by parents and others with whom the test results are to be shared. Subtest scaled scores are based on a distribution having a mean of 10 and standard deviation of 3. Composite indexes are based on a distribution having a mean of 100 and standard deviation of 15. Age equivalents are indexes of relative standing that translate subtest raw scores to what are commonly termed mental ages.

Access to the all-new DTLA-5 Online Scoring and Report System is now included with the purchase of each DTLA-5 Complete Kit and with the purchase of every replacement pack of Examiner Record Booklets. Inclusion of the software eliminates the need to include normative tables in the Examiner’s Manual and ensures accurate application of basals and ceilings and calculation of scores.

The Detroit Tests of Learning Abilities Fifth Edition (DTLA-5) Kit includes all items listed, including the Examiner's Manual, Picture Book 1 and 2, one package of 25 Examiner Record Forms, one package of 25 Student Response Forms, and access to the online scoring.