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Differential Ability Scales (DAS) Elliott, 1990

The DAS is an individual cognitive abilities test, developed and improved from the British Abilities Scales, for students of ages 2 through 17. It includes verbal, nonverbal (fluid reasoning), nonverbal/spatial, achievement, and special diagnostic tests. The DAS probably measures intellectual ability better than many competing tests because the special diagnostic tests are not included in the verbal, nonverbal, spatial, and total scores. The DAS was carefully normed on a stratified, random, national sample of 3,475 students. It is designed to be interpreted by both individual subtests and clusters of subtests, not merely by the total score, which is an important consideration for students with unusual patterns of strengths and weaknesses. Different subtests are used at the lower preschool, upper preschool, and school-age levels. It is handy to be able to compare the achievement tests to the cognitive ability tests within a single instrument, but unfortunately the achievement subtests measure only oral reading of words, written spelling, and math computation.

Verbal Subtests:

  • Verbal Comprehension: following oral instructions to point to or move pictures and toys.
  • Naming Vocabulary: naming pictures.
  • Word Definitions: explaining the meaning of each word. Words are spoken by the evaluator.
  • Similarities: explaining how three things or concepts go together, what they all are (e.g., house, tent, igloo; love, hate, fear)

Nonverbal/Spatial Subtests

  • Block Building: imitating constructions made by the examiner with wooden blocks.
  • Picture Similarities: multiple-choice matching of pictures on the basis of relationships, both concrete (e.g., two round things among other shapes) and abstract (e.g., map with globe from among other round things).
  • Copying: drawing pencil copies of abstract, geometric designs.
  • Recall of Designs: drawing pencil copies of abstract, geometric designs from memory after a 5-second view of each design.
  • Pattern Construction: copying geometric designs with colored tiles or patterned cubes. There are time limits and bonus points for fast work. An alternative "untimed" procedure uses time limits, but no speed bonuses.

Nonverbal (Fluid Reasoning) Subtests

  • Matrices: solving visual puzzles by choosing the correct picture or design to complete a logical pattern.
  • Sequential and Quantitative Reasoning: figuring out the mathematical relationship that relates the numbers in each of two pairs of numbers and applying that rule to another number to complete the third pair.

Early Number Concepts

  • Early Number Concepts: oral math questions with illustrations counting, number concepts, and simple arithmetic.

Achievement Subtests

  • Basic Number Skills: paper-and-pencil math computation.
  • Spelling: written spelling of dictated words, like a school spelling test.
  • Word Reading: accuracy of reading increasingly difficult words aloud from a list.

Diagnostic Subtests

  • Matching Letter-Like Forms: multiple-choice matching of shapes that are similar to letters.
  • Recall of Digits: repeating increasingly long series of digits dictated at two digits per second.
  • Recognition of Pictures: seeing one, two, or three pictures for five seconds or four pictures for ten seconds and then trying to find those pictures within a group of four to seven similar pictures.
  • Recall of Objects-Immediate: viewing a page of 20 pictures, hearing them named by the evaluator, trying to name the pictures from memory, seeing them again, trying again to name all the pictures, and repeating the process once more. The score is the total of all the pictures recalled on each of the three trials, including pictures recalled two or three times.
  • Recall of Objects-Delayed: trying to recall the pictures again on a surprise retest 15 to 20 minutes later.
  • Speed of Information Processing: the student scans rows of figures or numbers and marks the figure with the most parts or the greatest number in each row. The score is based on speed. Accuracy does not count unless it is very poor.