Anastasya Glezerman, Ph.D.
Compiled from the WISC-IV technical manual.
WISC-IV
1. Factor structure.
| Score | Composition | Is supposed to measure |
| Full Scale IQ (FSIQ) | Subtests listed below | An estimate of overall intellectual ability |
| Verbal Comprehension Index (VCI) | SimilaritiesVocabularyComprehensionInformationWord Reasoning | Verbal abilities utilizing reasoning, comprehension, and conceptualization |
| Perceptual Reasoning Index (PRI) | Block DesignPicture ConceptsMatrix ReasoningPicture Completion | Perceptual reasoning and organization |
| Working Memory Index (WMI) | Digit SpanLetter-Number SequencingArithmetic | Attention, concentration, working memory |
| Processing Speed Index (PSI) | CodingSymbol SearchCancellation | Speed of mental and graphomotor processing |
Supplemental subtests are italicized.
2. Subtests.
| Subtest | Is supposed to measure | Also measures |
| VERBAL COMPREHENSION SUBTESTS | ||
| Similarities | Verbal reasoning and concept formation | Auditory comprehension, memory, distinction between essential and nonessential features (appropriate level of abstraction), verbal expression |
| Vocabulary | Word knowledge and verbal concept formation | Fund of knowledge, learning ability, long-term memory, degree of language development, auditory perception and comprehension, verbal conceptualization, abstract thinking, verbal expression |
| Comprehension | Verbal reasoning and conceptualization, verbal comprehension and expression, ability to evaluate and use past experience, practical judgment | Knowledge of social conventions, social judgment and maturity, common sense |
| Information | Ability to acquire, retain and retrieve general factual knowledge | Crystallized intelligence, long-term memory, ability to retain and retrieve information from school and environment, auditory perception and comprehension, verbal expressive ability |
| Word Reasoning | Verbal comprehension, analogical and general reasoning ability, verbal abstraction, domain knowledge, ability to integrate and synthesize different types of information, ability to generate alternative concepts | ?(Nothing in the manual, but think about it) |
| PERCEPTUAL REASONING SUBTESTS | ||
| Block Design | Ability to analyze and synthesize abstract visual stimuli | Nonverbal concept formation, visual perception, organization, simultaneous processing, visual-motor coordination, learning, figure-ground discrimination, visual observation, matching, visual-motor integration |
| Picture Concepts | Abstract categorical reasoning ability | Huh? |
| Matrix Reasoning | Fluid intelligence (good FSIQ estimate, no language or motor demands); tasks include : continuous and discrete pattern completion, classification, analogical reasoning, and serial reasoning | ? |
| Picture Completion | Visual perception and organization, concentration, recognition of essential details | ? |
| WORKING MEMORY SUBTESTS | ||
| Digit Span | Auditory short-term memory, sequencing, attention, concentration | ? |
| Letter-Number Sequencing | Sequencing, mental manipulation, attention, short-term auditory memory, visuospatial imaging, processing speed | ? |
| Arithmetic | Mental manipulation, concentration, attention, short- and long-term memory, numerical reasoning ability, mental alertness | Sequencing, fluid reasoning, logical reasoning |
| PROCESSING SPEED SUBTESTS | ||
| Coding | Processing speed | Short-term memory, learning ability, visual perception, visual-motor coordination, visual scanning ability, cognitive flexibility, attention, motivation, visual and sequential processing |
| Symbol Search | Processing speed | Short-term visual memory, visual-motor coordination, cognitive flexibility, visual discrimination, concentration, auditory comprehension, perceptual organization, planning and learning ability |
| Cancellation | Processing speed, visual selective attention, vigilance, visual neglect | ? |
3. Process Scores (make sure to check base rates during comparisons).
| Score | Supposed to measure |
| Block Design No Time Bonus | Excludes the speed effects from Block Design |
| Digit Span Forward | Rote learning, memory, attention, encoding, auditory processing |
| Digit Span Backward | Working memory, transformation of information, mental manipulation, visuospatial imaging |
| Longest Digit Span Forward | Controls for intrasubtest scatter on DSF |
| Longest Digit Span Backward | Controls for intrasubtest scatter on DSB |
| Cancellation Random | Random arrangement scanning efficiency |
| Cancellation Structured | Structured arrangement scanning efficiency |
4. Manual Definitions of What is Measured
Fluid Reasoning: “manipulating abstractions, rules, generalizations, and logical relationships”.
Working Memory: “ability to actively maintain information in conscious awareness, perform some operation or manipulation with it, and produce a result”. Research indicates that WM is an essential component of fluid reasoning and other executive processes and is closely related to achievement and learning.
Processing Speed: “ speed of information processing”. Research indicates that it is related to mental capacity, reading performance, development, economical reasoning, and efficient use of working memory for fluid tasks. It is sensitive to epilepsy, ADHD and TBI. Increase is correlated with age-related increase in neuronal connectivity and myelinization.
5. Special Group Studies (data on pp.75-98, inclusion criteria on pp. 146-149)
| Groups | Basic Stats (almost all groups are mostly white) |
| Gifted | N=63, Mean age = 11, Age SD = 2.3 |
| Mild Mental Retardation | N=63, Mean age = 11.9, Age SD = 3.0 |
| Moderate Mental Retardation | N=57, Mean age = 12.2, Age SD = 2.8 |
| Reading Disorder | N=63, Mean age = 10.7, Age SD = 1.5 |
| Reading and Written Expression Disorder | N=35, Mean age = 10.9, Age SD = 1.6 |
| Mathematics Disorder | N=33, Mean age = 10.7, Age SD = 1.6 |
| Reading and Written Expression and Mathematics Disorder | N=42, Mean age = 10.5, Age SD = 1.6 |
| Learning Disorder and ADHD | N=45, Mean age = 11, Age SD = 1.4 |
| ADHD | N=89, Mean age = 10.7, Age SD = 1.4 |
| Expressive Language Disorder | N=27, Mean age = 9.8, Age SD = 2.8 |
| Mixed Receptive-Expressive Language Disorder | N=41, Mean age = 10.6, Age SD = 2.9 |
| Open Head Injury | N=16, Mean age = 12.6, Age SD = 2.7 |
| Closed Head Injury | N=27, Mean age = 13.4, Age SD = 3.1 |
| Autistic Disorder | N=19, Mean age = 11.7, Age SD = 2.6 |
| Asperger’s Disorder | N=27, Mean age = 12.5, Age SD = 1.9 |
| Motor Impairment | N=21, Mean age = 10.1, Age SD = 2.4 |
