Wechsler Adult Intelligence Scale Wechsler–Bellevue Intelligence Scale The Non-Verbal Performance Scale

WAIS-IV subtests grouped by index

Index	Subtest	Core?	Description	Proposed abilities measured
Verbal Comprehension	Similarities		Describe how two words or concepts are similar.	Abstract verbal reasoning; semantic knowledge
	Vocabulary		Name objects in pictures or define words presented to them.	Semantic knowledge; verbal comprehension and expression
	Information		General knowledge questions	Degree of general information acquired from culture
	Comprehension		Questions about social situations or common concepts.	Ability to express abstract social conventions, rules and expressions
Perceptual Reasoning	Block Design		Put together red-and-white blocks in a pattern according to a displayed model. This is timed, and some of the more difficult puzzles award bonuses for speed.	Visual spatial processing and problem solving; visual motor construction
	Matrix Reasoning		View an array of pictures with one missing square, and select the picture that fits the array from five options.	Nonverbal abstract problem solving, inductive reasoning
	Visual Puzzles		View a puzzle in a stimulus book and choose from among pieces of which three could construct the puzzle	Visual spatial reasoning
	Picture Completion		Select the missing part of a picture	Ability to quickly perceive visual details
	Figure Weights		View a stimulus book that pictures shapes on a scale (or scales) with one empty side and select the choice that keeps the scale balanced	Quantitative reasoning
Working Memory	Digit Span		Listen to sequences of numbers orally and to repeat them as heard, in reverse order, and in ascending order.	Working memory, attention, encoding, auditory processing
	Arithmetic		Orally administered arithmetic word problems. Timed.	Quantitative reasoning, concentration, mental manipulation
	Letter-Number Sequencing		Recall a series of numbers in increasing order and letters in alphabetical order.	Working memory, attention, mental control
Processing Speed	Symbol Search		View rows of symbols and target symbols, and mark whether or not the target symbols appear in each row.	Processing speed
	Coding		Transcribe a digit-symbol code using a key. The task is time-limited.	Processing speed, associative memory, graphomotor speed
	Cancellation		Scan arrangements of shapes and mark specific target shapes within a limited amount of time	Processing speed

it can be used as a measure of cognitive abilities that are less vulnerable to impairments of processing speed and working memory.
Index scores and scales[edit]
There are four index scores representing major components of intelligence:

• 
  Verbal Comprehension Index (VCI)
  
• 
  Perceptual Reasoning Index (PRI)
  
• 
  Working Memory Index (WMI)
  
• 
  Processing Speed Index (PSI)
  

Two broad scores, which can be used to summarize general intellectual ability, can also be derived:

• 
  Full Scale IQ (FSIQ), based on the total combined performance of the VCI, PRI, WMI, and PSI
  
• 
  General Ability Index (GAI), based only on the six subtests that the VCI and PRI comprise.
  

Standardization[edit]
The WAIS-IV was standardized on a sample of 2,200 people in the United States, ranging in age from 16 to 90.^[10] The demographic characteristics of the sample were modeled after the proportions of different groups in an analysis of data from the U.S. Census Bureau. An extension of the standardization has been conducted with 688 Canadians in the same age range.
Age range and uses[edit]
The WAIS-IV measure is acceptable for use with people who are 16–90 years of age. For people younger than 16, the Wechsler Preschool and Primary Scale of Intelligence (WPPSI, 2½–7 years, 7 months) and the Wechsler Intelligence Scale for Children (WISC, 6–16 years) are used.^[11]
Intelligence tests may be used to assess the level of cognitive functioning in individuals with psychiatric illness or brain injury. Rehabilitation psychologists and neuropsychologists use neuropsychological tests (including the WAIS-IV) to assess how the individual's brain is functioning after it has been injured. Specific subtests can provide insight into specific cognitive functions; for example, the digit span subtest could be used to look for attentional difficulties.^[11]
The Wechsler tests can also be used to identify intellectual giftedness, and are commonly accepted as qualifying evidence for high-IQ societies, such as Mensa, Intertel and the Triple Nine Society.^[12][13][14]
WASI-II[edit]
The Wechsler Abbreviated Scale of Intelligence - 2nd edition (WASI-II) is a short psychological test that was developed in 2011 by Pearson to estimate intellectual functioning in a shorter period of time than the WAIS-IV.^[15] The WASI-II only has 4 subtests: Block Design, Vocabulary, Similarities, and Matrix Reasoning, compared to the 10 core subtests that are present in the WAIS-IV. These 4 subtests have the same structure as the similarly-named subtests on the WAIS-IV, but have different questions.
The WASI-II can derive 4 composite scores from a combination of the 4 subtests. A Verbal Comprehension Index (VCI) can be dervied from the raw scores on the Vocabulary and Similarities subtests. A Perceptual Reasoning Index (PRI) can be derived from the raw scores on the Matrix Reasoning and Block Design subtests. A Full Scale IQ-2 (FSIQ-2) can be derived from the raw scores on the Matrix Reasoning and Vocabulary subtests, while a Full Scale IQ-4 (FSIQ-4) can be derived from the raw scores on all 4 subtests.