Block Design measures an individual’s ability to analyze and synthesize an abstract design and reproduce that design from colored plastic blocks. Spatial visualization and analysis, simultaneous processing, visual-motor coordination, dexterity, and nonverbal concept formation are involved. The students use logic and reasoning to successfully complete the items.

Similarities measures logical thinking, verbal concept formation and verbal abstract reasoning. Two similar but different objects or concepts are presented, and the student is asked to tell how they are alike or different.

Digit Span measures short-term auditory memory and attention. The digits have no logical relationship to each other and are presented in random order by the examiner. The student must then recite the digits correctly by recalling them in the same order. On the second part of this subtest the student must remember the order in which digits are presented, but recite them in reverse order.

Picture Concepts measures categorical, abstract reasoning, and the items here increase in difficulty. Students are asked to look at two (or three) rows of pictured objects and indicate (by pointing) the single picture from each row that shares a characteristic in common with the single picture(s) from the other row(s).

Coding measures visual-motor dexterity, associative nonverbal learning, and nonverbal short-term memory. Fine-motor dexterity, speed, accuracy and ability to manipulate a pencil contribute to task success; perceptual organization is also important.

Vocabulary measures the students’ verbal fluency and concept formation, word knowledge, and word usage. Here’s one subtest in which prior knowledge does play a role.

Letter-Number Sequencing measures attention span, short-term auditory recall, processing speed and sequencing abilities. The task involves listening to and remembering a string of digits and letters read aloud at a speed of one per second, then recalling the information by repeating the numbers in chronological order, followed by the letters in alphabetical order.

Matrix Reasoning measures visual processing and abstract, spatial perception and may be influenced by concentration, attention, and persistence.

Comprehension is not just ordinary reading comprehension; this subtest measures the students’ common-sense social knowledge, practical judgment in social situations, and level of social maturation, along with the extent of development of their moral conscience.

Symbol Search requires the student to determine whether a target symbol appears among the symbols shown in a search group. Memory is not a primary requirement for success on this task; perception and recognition are the two prime requirements, in addition to speed, accuracy, attention, and concentration. The symbols are geometric forms, rather than familiar letters or numbers.

Picture Completion measures a student's ability to recognize familiar items and to identify missing parts. The student's task is to separate essential and nonessential parts from the whole. It is necessary to observe each item closely and concentrate on picture detail. Students must name or indicate the missing part by saying the name of the part or by pointing to it.

Cancellation measures visual vigilance/neglect, selective attention, and speed in processing visual information in accordance with previous attempts along the same line.

Information measures general cultural knowledge, long-term memory, and acquired facts. Here’s another subtest that challenges students to remember what has been taught previously in school.

Arithmetic measures numerical accuracy, reasoning and mental arithmetic ability. Mental arithmetic and story problems play an important part in the student’s success.

Word Reasoning measures verbal abstract reasoning requiring analogical and categorical thinking, as well as verbal concept formation and expression.

Perceptual Reasoning Index measures perceptual and organizational skills, reflecting ability to interpret reason with, and/or organize visually perceived material.