WISC-V Subtest & Index Reference — CHC Theory

Score Classification Ranges

Classification	Standard Score	Scaled Score (subtests)	Percentile	Interpretation note
Very Superior	130+	17–19	98th+	Exceptionally high; significantly above same-age peers
Superior	120–129	15–16	91st–97th	Well above average for age
High Average	110–119	13–14	75th–90th	Above average; a relative strength
Average	90–109	8–12	25th–73rd	Within typical range for age
Low Average	80–89	6–7	9th–23rd	Below average; borderline range — monitor in full profile context
Low	70–79	4–5	2nd–8th	Significantly below average; notable weakness
Very Low / Extremely Low	≤69	1–3	Below 2nd	Well below average; interpret with behavioral observations and adaptive data

Standard scores: M=100, SD=15 · Scaled scores: M=10, SD=3 · WISC-V uses "Extremely Low" for SS ≤69; many Texas FIE reports use "Very Low" for consistency with WJ-V language.

Verbal Comprehension Index

VCI | Standard Score, M=100 SD=15

Measures the ability to access and apply previously acquired word knowledge, verbal reasoning, and crystallized intelligence. Reflects language development, vocabulary breadth, and the ability to reason with verbal information. Highly dependent on educational opportunity and language exposure.

CHC: Gc (Crystallized Intelligence) — acquired knowledge through verbal reasoning and language

Classroom Connection High VCI supports reading comprehension, vocabulary acquisition, and verbal instruction. Low VCI may reflect limited language exposure, a language-based LD, or EL factors — interpret carefully in context.

Similarities

CORE

What it measures

Student identifies how two concepts are alike (e.g., "In what way are a cat and a dog alike?"). Requires verbal abstract reasoning and categorical thinking.

CHC: Gc — Lexical Knowledge, Language Development; Gf — Inductive Reasoning

Low score in the classroom

Difficulty categorizing concepts, making connections across subjects, and understanding thematic relationships in text. May struggle with compare/contrast tasks and verbal analogies.

Vocabulary

CORE🔠 DYSLEXIA

What it measures

Student names pictured objects (younger ages) and defines words orally. Assesses breadth and depth of vocabulary and word knowledge.

CHC: Gc — Lexical Knowledge, Language Development

Low score in the classroom

Limited vocabulary affects reading comprehension, oral language, and the ability to express ideas in writing. Students may substitute general words for precise terms or misunderstand content-area vocabulary.

🔠 Vocabulary knowledge is a key protective factor in dyslexia; strong Gc with low decoding scores supports a language-based LD profile. Discrepancies between vocabulary and word-reading fluency are diagnostically meaningful.

Information

SUPP

What it measures

Student answers general knowledge questions about history, science, geography, and culture. Reflects breadth of educational/cultural knowledge accumulated over time.

CHC: Gc — General Information, Language Development

Low score in the classroom

Limited background knowledge can impede reading comprehension and content-area learning. May reflect limited educational opportunity, EL background, or infrequent reading. Low scores should be interpreted cautiously for students from underrepresented backgrounds.

Comprehension

SUPP

What it measures

Student answers questions about everyday situations and social conventions (e.g., "Why do we have traffic laws?"). Measures practical social knowledge, common sense reasoning, and verbal expression of reasoning.

CHC: Gc — General Information; Gk — General Knowledge

Low score in the classroom

May struggle applying reasoning to real-world contexts, understanding cause-and-effect in text, and interpreting social situations. Relevant to understanding pragmatic reasoning in students suspected of ASD or social-emotional difficulties.

Visual Spatial Index

VSI | Standard Score, M=100 SD=15

Measures the ability to evaluate visual details, understand part-whole relationships, and mentally manipulate visual information. Reflects visuospatial reasoning and the ability to construct and analyze visual-spatial patterns.

CHC: Gv (Visual Processing) — spatial visualization, mental rotation, and visual-spatial reasoning

Classroom Connection VSI supports geometry, maps, diagrams, and understanding spatial concepts. Generally less central to dyslexia profiles — a deficit here alongside intact language skills may suggest a non-verbal learning profile.

Block Design

CORE

What it measures

Student uses red-and-white blocks to replicate a 2D design shown in a model or picture within a time limit. Assesses visual-spatial analysis, part-whole reasoning, and mental manipulation of visual forms.

CHC: Gv — Visualization (Vz), Spatial Relations (SR)

Low score in the classroom

Difficulty with geometry, copying from the board, understanding diagrams, and organizing written work spatially. May also affect handwriting layout and reading multi-step math problems.

Visual Puzzles

CORE

What it measures

Student selects three puzzle pieces that together form a target image. Measures the ability to mentally decompose and reconstruct abstract visual designs without a motor component.

CHC: Gv — Visualization (Vz), Spatial Relations (SR); no motor output requirement distinguishes this from Block Design

Low score in the classroom

Challenges with visualizing how parts form a whole — impacts understanding diagrams, maps, and spatial reasoning in math. Comparing Block Design vs Visual Puzzles can help tease apart visual-spatial ability from motor speed.

Figure Weights

SUPP

What it measures

Student views a balance scale and determines which option balances it. Measures quantitative and analogical reasoning through visual-spatial means.

CHC: Gf — Inductive/Deductive Reasoning; Gv — Spatial Relations (Note: also loads on FRI in some administrations)

Low score in the classroom

Difficulty with proportional reasoning, math word problems involving balance/equality, and seeing quantitative relationships. Can support interpretation of math reasoning weaknesses.

Fluid Reasoning Index

FRI | Standard Score, M=100 SD=15

Measures the capacity to detect underlying conceptual relationships among visual objects and use reasoning to identify and apply rules. Often considered a strong indicator of general learning potential because it is less dependent on prior knowledge and language background.

CHC: Gf (Fluid Reasoning) — inductive and deductive reasoning with novel information

Classroom Connection Strong FRI with weak academic achievement (especially reading) is a hallmark of dyslexia profiles — supports discrepancy-based and XBA reasoning. High FRI can also be leveraged for problem-based instruction.

Matrix Reasoning

CORE🔠 DYSLEXIA

What it measures

Student views an incomplete matrix of abstract figures and selects the missing piece. Measures the ability to identify visual patterns and apply inductive reasoning rules.

CHC: Gf — Inductive Reasoning (I); Gv — Visualization

Low score in the classroom

Difficulty identifying patterns and rules in new material, generalizing learned strategies to novel tasks, and understanding sequencing in multi-step problems.

🔠 Average or above Matrix Reasoning with significantly below-average reading is consistent with a specific learning disability profile. Supports argument that poor reading is not due to low general reasoning ability.

Figure Weights

CORE

What it measures

Student completes balance scale problems requiring quantitative-visual reasoning. Assesses inductive and analogical reasoning with quantitative content.

CHC: Gf — Inductive Reasoning, Quantitative Reasoning (RQ)

Low score in the classroom

Struggles with proportional reasoning, identifying numerical relationships, and quantitative pattern completion in math problem-solving contexts.

Picture Concepts

SUPP

What it measures

Student selects one picture from each of two or three rows to form a group with a shared characteristic. Measures categorical inductive reasoning using visual stimuli.

CHC: Gf — Inductive Reasoning (I); Gc — General Information

Low score in the classroom

Difficulty categorizing concepts across subject areas and making inferential connections during reading. Can indicate challenges with concept formation and classification.

Arithmetic

SUPP

What it measures

Orally presented math problems solved mentally without pencil/paper. Measures mental math, quantitative reasoning, and working memory for numerical information simultaneously.

CHC: Gf — Quantitative Reasoning (RQ); Gwm — Working Memory (overlaps with WMI)

Low score in the classroom

Difficulty with mental math, solving word problems without written support, and holding numerical information in mind during multi-step calculation. Low scores here alongside low WMI are particularly impactful for math instruction.

Working Memory Index

WMI | Standard Score, M=100 SD=15

Measures the ability to temporarily hold, organize, and mentally manipulate information in immediate awareness. Working memory is a strong cross-domain predictor of academic achievement — particularly for reading comprehension, written composition, and math problem solving.

CHC: Gwm (Short-Term Working Memory) — capacity to hold and transform information in immediate awareness

Classroom Connection Low WMI has broad academic impact — affects every task requiring the student to hold information while doing something else. Frequently co-occurs with ADHD, dyslexia, and DLD profiles.

Digit Span

CORE🔠 DYSLEXIA

What it measures

Three components: Forward (simple recall of spoken digit sequences), Backward (recalling digits in reverse order), and Sequencing (arranging digits in ascending order). Separates rote memory from manipulation and sequencing of held information.

CHC: Gwm — Memory Span (Forward); Working Memory Capacity (Backward, Sequencing)

Low score in the classroom

Difficulty retaining and following multi-step directions, losing place during mental math, forgetting the beginning of a sentence while decoding the end, and organizing thought in oral or written expression. Backward and Sequencing are typically more sensitive than Forward for LD profiles.

🔠 Phonological working memory deficits are a core feature of dyslexia. Low Digit Span — especially Backward/Sequencing — alongside phonological awareness weaknesses strengthens the dyslexia hypothesis. Also relevant to DLD profiles.

Picture Span

CORE

What it measures

Student views a page of pictures briefly, then identifies those pictures (in order) from a larger response page. Measures visual working memory span using nonverbal stimuli — a useful complement to Digit Span for separating verbal vs visual WM.

CHC: Gwm — Memory Span (visual modality); Gv — Visual Memory

Low score in the classroom

Difficulty tracking visual sequences, remembering what was seen on a page, and retaining visual information during note-taking or copying tasks. Comparing Picture Span to Digit Span can help characterize whether WM weakness is modality-specific.

Letter-Number Sequencing

SUPP🔠 DYSLEXIA

What it measures

Student hears a mixed sequence of letters and numbers, then recalls the numbers in ascending order followed by letters in alphabetical order. Requires mental manipulation, sequencing, and dual-tracking of verbal information.

CHC: Gwm — Working Memory Capacity; requires phonological coding and sequencing

Low score in the classroom

Difficulty with tasks requiring mental organization and sequencing — following complex oral instructions, tracking narrative structure in reading, and composing organized written responses.

🔠 Requires phonological coding of letters and numbers; sensitive to phonological working memory deficits seen in dyslexia and DLD. Low LNS + low Digit Span Backward is a strong working memory pattern in language-based LD profiles.

Processing Speed Index

PSI | Standard Score, M=100 SD=15

Measures the speed and accuracy of processing simple visual information. Reflects cognitive efficiency and the ability to perform rote tasks quickly under time pressure. PSI is frequently lowered in profiles involving ADHD, dyslexia, anxiety, and fine motor difficulties.

CHC: Gs (Processing Speed) — rate of performing simple, automatic, clerical-type tasks

Classroom Connection Low PSI affects timed testing, reading fluency, written output speed, and completing multi-step tasks within time limits. Accommodations (extended time, reduced written output) are directly supported by PSI deficits.

Coding

CORE🔠 DYSLEXIA

What it measures

Student uses a key to write symbols paired with numbers (or shapes/symbols for younger children) as quickly and accurately as possible in a timed task. Requires visual scanning, symbol association, fine motor coordination, and sustained attention.

CHC: Gs — Rate of Test-Taking (R9); associative memory; fine motor; sustained attention

Low score in the classroom

Slow written output, difficulty completing timed work, reduced copying efficiency, and fatigue during writing-heavy tasks. Fine motor demands make this partially a measure of graphomotor speed.

🔠 Coding taps symbol-sound association automaticity and visual-motor speed — processes implicated in reading fluency. Low Coding alongside low CTOPP-2 RAN subtests forms a strong rapid naming / automaticity profile consistent with dyslexia.

Symbol Search

CORE🔠 DYSLEXIA

What it measures

Student scans a row of symbols and marks whether a target symbol is present among search symbols. Timed. Measures visual scanning speed, discrimination, and focused attention without significant motor output.

CHC: Gs — Perceptual Speed (P); visual discrimination; sustained attention

Low score in the classroom

Slow visual scanning affects timed reading tasks, finding information on a page, and completing reading comprehension assessments within time limits. Less motor-dependent than Coding — comparing the two helps separate graphomotor slowness from general visual processing speed.

🔠 Visual scanning speed underlies orthographic processing efficiency. Low Symbol Search alongside TOC weaknesses suggests slow visual symbol processing that contributes to dysfluent reading and spelling difficulties.

Cancellation

SUPP

What it measures

Student scans and marks target animal pictures among non-target objects (Random and Structured formats). Measures visual processing speed, focused attention, and the ability to scan systematically vs randomly arranged stimuli.

CHC: Gs — Attentional Speed; visual attention; inhibition

Low score in the classroom

Difficulty with visual search tasks, locating information on a page, and tasks requiring sustained visual attention. Comparing Random vs Structured formats can inform whether the student benefits from visual organization. Relevant for ADHD profiles.

Full Scale IQ & Composite Scores

FSIQ, GAI, CPI, NVI, ELI | Standard Score, M=100 SD=15

The WISC-V provides several composite scores beyond the five primary indices. The FSIQ is the primary global ability estimate. Ancillary composites allow interpretation when the profile is variable or when certain indices are contraindicated.

Full Scale IQ (FSIQ)

PRIMARY

Subtests included

Block Design, Similarities, Matrix Reasoning, Digit Span, Coding (core battery = 10 subtests total)

What it represents

Overall estimate of general intellectual ability across verbal, visual-spatial, fluid reasoning, working memory, and processing speed domains. Best single estimate of global cognitive functioning when the profile is relatively consistent.

Cautions

When index scores are highly discrepant (e.g., 30+ point spread), the FSIQ may not be a valid summary. In such cases, ancillary composites (GAI, CPI) provide more interpretable estimates. Always report and interpret index scores in dyslexia and ADHD evaluations — the FSIQ alone is insufficient.

General Ability Index (GAI)

ANCILLARY🔠 DYSLEXIA

Subtests included

VCI + FRI subtests only (excludes WMI and PSI)

What it represents

Estimates general ability with reduced influence of working memory and processing speed. Useful when WMI and/or PSI are significantly lower than reasoning abilities — common in dyslexia, ADHD, and anxiety profiles.

🔠 In dyslexia evaluations, GAI often provides a more accurate estimate of intellectual potential than FSIQ when WMI and PSI are depressed by processing speed and phonological memory deficits. GAI > FSIQ by 10+ points is clinically significant in these profiles.

Cognitive Proficiency Index (CPI)

ANCILLARY🔠 DYSLEXIA

Subtests included

WMI + PSI subtests only

What it represents

Estimates cognitive efficiency — the speed and capacity for processing basic information. CPI is separate from higher-order reasoning (captured in GAI).

🔠 GAI–CPI discrepancy is one of the most interpretable WISC-V patterns in dyslexia/SLD evaluations. High GAI + Low CPI means strong reasoning ability paired with inefficient processing — a hallmark pattern. Supports accommodations (extended time, reduced written output) and intervention targeting fluency and automaticity.

Nonverbal Index (NVI)

ANCILLARY

Subtests included

Block Design, Visual Puzzles, Matrix Reasoning, Figure Weights, Picture Span, Coding

What it represents

Global ability estimate using only nonverbal tasks. Appropriate when language barriers, expressive language impairments, or hearing impairments make verbal tasks invalid or uninterpretable.

Note for bilingual/EL evaluations

NVI can be used as a supplementary estimate in evaluations where English language proficiency limits VCI validity, though the WJ-V Batería remains the preferred instrument for Spanish-dominant students. Document rationale clearly in the FIE.

Expanded Fluid Index (EFI)

ANCILLARY

Subtests included

Matrix Reasoning, Figure Weights, Picture Concepts, Arithmetic

What it represents

Broader fluid reasoning estimate that adds quantitative and categorical inductive reasoning to the core FRI subtests. Useful when a more comprehensive Gf estimate is needed beyond the standard FRI.

🧠 WISC-V Subtest Reference