Verbal IQ and Performance IQ on an old report, and what replaced them

0 The short answer

Verbal IQ and Performance IQ were the two half scores printed beside the Full Scale IQ on Wechsler adult reports from the 1939 Wechsler-Bellevue through the WAIS-III, and the WAIS-IV, published in 2008, stopped reporting both. On the WAIS-III the Verbal IQ summed six subtests and the Performance IQ five, and several of those subtests tapped working memory or speed rather than verbal or visual reasoning. Pearson's manual tells examiners to substitute the Verbal Comprehension Index and the Perceptual Reasoning Index, which use three subtests each, so an old Verbal IQ is a related score and not the same one.

1 What Were Verbal IQ and Performance IQ on a Wechsler Report?

Verbal IQ and Performance IQ were two separate IQ scores, each computed from its own group of subtests, reported next to a Full Scale IQ that combined both groups. The arrangement began with the Wechsler-Bellevue Intelligence Scale of 1939. In the third edition of the book that introduced it, Wechsler described a Full Scale made of five verbal tests and five performance tests, so that verbal and performance abilities carried equal weight. The verbal tests in his tables were Information, Comprehension, Arithmetic, Digit Span and Similarities. The performance tests included Picture Arrangement, Picture Completion, Block Design, Object Assembly and Digit Symbol.

The word "performance" had a plain meaning. A verbal subtest asks the person to answer in words, for example to define a term or explain how two things are alike. A performance subtest asks the person to do something with materials in hand, such as assembling blocks or arranging picture cards, so that the answer is an action. Boake's history of the Wechsler scales traces the subtests to tests developed between 1880 and World War I, among them the Binet-Simon scales, language-free performance testing of immigrants and school children, and group testing of military recruits. The structure that Wechsler built in 1939, Boake notes, remained almost unchanged through later revisions.

That continuity is why so many people hold a report with the two numbers. The WAIS-III, published in 1997, still gave a Verbal IQ and a Performance IQ, as Kaufman, Lichtenberger and McLean point out in a paper on its factor structure. Children tested on the Wechsler Intelligence Scale for Children before its fourth edition also received the pair, according to a Pearson technical report on the General Ability Index, which lists the original WISC (1949), the WISC-R (1974) and the WISC-III as scales that included a Full Scale IQ plus a Verbal IQ and a Performance IQ.

Two features of these reports matter for what follows. First, the two scores were deviation IQs, ranked against people of the same age on a scale with an average of 100, so a Verbal IQ of 115 and a Performance IQ of 100 described a standing relative to peers and not a count of items correct. The page on how IQ scores are normed explains that logic, and the page on the standard deviation of 15 explains the unit. Second, the labels "verbal" and "performance" described the format of the task, which is a different thing from the ability the task draws on. Block Design is a performance subtest by format, yet the ability it draws on is visual and spatial reasoning, and Digit Span is a verbal subtest by format, yet the ability it draws on is working memory. That mismatch between format and ability is the thread that runs through the rest of this page.

The page on what a verbal IQ test measures covers how a verbal index is built today. This page covers the old pair.

2 Why Did Wechsler Split the Scale in Two?

Wechsler split his scale into a verbal part and a performance part because he believed that tests of words and reasoning used alone gave an incomplete picture of intelligence, and not because he believed there were two kinds of intelligence. The reasoning is on the page in his third edition of 1944. He argued that the tests he called performance tests were an attempt to capture more than narrow verbal and abstract skill, and he wrote that tests of verbal ability and abstract reasoning, when used alone in a general intelligence examination, give only an incomplete picture of a person's capacity for effective adjustment and achievement (Wechsler, 1944, pages 11 and 12).

His starting point was dissatisfaction with the instruments of his day. Wechsler wrote that the Army Alpha and Beta group tests, given to more than a million men, were the most thoroughly standardized group tests yet devised. Of the Alpha test he wrote that its merit was a rapid examination and classification of many people in a short time, and that it did not furnish means for an individual diagnosis. He was then chief psychologist at Bellevue Psychiatric Hospital, where individual adult diagnosis was the daily task. Boake adds that Wechsler's choice of subtests can be understood partly from his clinical experience in World War I.

The most direct statement of his view comes in his discussion of what an examiner should do when a person's two scores differ. Wechsler considered three options: prefer one of the two results, take the higher one, or average them. He rejected the first because it assumes there are different kinds of general intelligence and implies that performance tests are relatively unimportant as measures of general intelligence. He wrote that his scale was constructed on the hypothesis that a person shows intelligence by the ability to do things as well as by the way the person can talk about them. He rejected the second, taking the higher score, because he did not believe that any test that is predominantly verbal or nonverbal can alone completely measure general intelligence. He chose the third, so that the Full Scale gave equal weight to the two kinds of task (Wechsler, 1944, pages 137 and 138).

Read closely, that is an argument for a single general score built from two kinds of evidence. The split was a design for coverage, with two sets of tasks that approach the same underlying capacity from different sides. Wechsler did not present it as proof that verbal and performance abilities are separate faculties. The page on the g factor describes the general factor that a Full Scale score is meant to estimate, and the page on the history of IQ testing places his scale between Binet and the modern batteries.

There is one caution in the same passage that readers of old reports tend to miss. Wechsler wrote that it would be unfair to use a combined verbal and performance scale on people with motor or visual defects or a special language handicap, and that for such people it is often better to use one type of scale rather than the other. He saw the two halves as useful partly because one half could be set aside when the other was blocked by a handicap. That use survives today in a different form, which the section on the WAIS-5 returns to.

3 What Did a Gap Between the Two Scores Mean?

A gap between Verbal IQ and Performance IQ was common even among people with no known difficulty, and Wechsler's own standardization data show that a difference of several points was typical. In the same book Wechsler reports that examiners were struck by differences between the two IQs, and that some saw the fact as an advantage and others as a limitation. It raised the question of whether verbal and performance items could legitimately be combined in a single scale. The cases that drew attention were those with differences of 10 to 15 points or more. Some of those people had psychomotor or foreign language handicaps, but many had no special defect that could be named.

To find out how the matter stood among people drawn from the general population, Wechsler examined the differences in his standardization sample. The mean difference between the Verbal and Performance IQ was 8.4 points among 590 cases aged 20 to 49 and 9.1 points among 520 cases aged 10 to 16. He noted that these differences could not have been predicted from the correlation between the two batteries, which he gave as .83, nor from their mean IQs, which for the whole population were 100.75 for the Performance IQ and 100.11 for the Verbal IQ (Wechsler, 1944, pages 136 and 137). These figures describe the first Wechsler scale, normed in the 1930s, and not the WAIS-III or any current test. They do show the basic fact about two imperfectly correlated scores, which is that gaps of several points are ordinary.

The practical lesson follows his method, which was to ask how the matter stood among normal subjects, and it holds for any pair of scores. A difference between two IQs of the same person is not a finding until it is compared with how often differences of that size occur in the norm group. A report that prints a 12 point gap without saying how common that gap is has not told the reader whether it matters. The sibling page on index score differences answers the question of how large a gap between index scores is unusual on current tests, and this page leaves that question to it.

Two further points belong with the history. The size of a gap says nothing about its cause, and no group statistic of this kind amounts to a diagnosis of any person. And Wechsler himself noted that large gaps often accompanied psychomotor or foreign language handicaps, and equally that many large gaps had no nameable cause.

Later authors disagreed about how much weight the pair could bear, and the factor analyses below bear on that disagreement directly. First it helps to see how the index scores came to sit beside the pair.

4 How Did Index Scores Come to Sit Beside the Pair?

Index scores were added next to the Verbal IQ and Performance IQ first for children, on the WISC-III, and then for adults, on the WAIS-III, so for years a single report printed both systems side by side. According to the Pearson technical report on the General Ability Index, the WISC-III introduced four index scores for narrower domains: Verbal Comprehension, Perceptual Organization, Freedom from Distractibility and Processing Speed. Together with the Full Scale IQ, the Verbal IQ and the Performance IQ, that made seven composite scores on one report.

The same report explains why the extra scores were useful, and in doing so it records the weakness of the old pair in the publisher's own words. A practitioner could describe verbal ability with the Verbal Comprehension Index in place of the Verbal IQ when Arithmetic, a working memory subtest, differed from the verbal comprehension subtests by an amount that was unusual in the standardization sample. A practitioner could likewise describe perceptual ability with the Perceptual Organization Index in place of the Performance IQ when Coding, a processing speed subtest, differed unusually from the perceptual organization subtests. In both cases the old score had absorbed a subtest from a different domain, and the index score was the cleaner summary.

The adult scale followed the same path. Kaufman, Lichtenberger and McLean report that the WAIS-III manual presents four-factor solutions, that later research validated four-factor solutions in a variety of samples, and that the four factors consistently correspond to the four index scores the test yields. They add that the WAIS-III still provided Verbal and Performance IQs in addition to the indexes. A full WAIS-III report therefore carried a Full Scale IQ, a Verbal IQ, a Performance IQ and four indexes. The Pearson report notes that the General Ability Index, a score built from the verbal and perceptual subtests alone, was also applied to the WAIS-III, and the page on the General Ability Index describes how it is used now.

This dual system had a cost that anyone holding an older report can see. Two numbers that both seemed to describe verbal ability, the Verbal IQ and the Verbal Comprehension Index, could disagree within one report. A person with strong verbal comprehension and weaker working memory could show a modest Verbal IQ and a higher Verbal Comprehension Index, because only the first contained working memory subtests. The explanation was in the manual and not on the summary page.

The WISC-IV, published in 2003, ended the arrangement for children. The Pearson report states that in that edition the dual IQ and index score structure was no longer used. The adult scale did the same five years later, and Canivez's review of the WAIS-IV in the Buros Mental Measurements Yearbook records that the Verbal IQ and the Performance IQ were no longer provided, as with the WISC-IV. Before turning to the reasons, it helps to look at what the factor analyses of the WAIS-III had found, because the retirement of the pair was argued from that evidence.

5 What Did Factor Analysis Show About the Two-Part Split?

Factor analysis of the WAIS-III standardization data supported four clusters of subtests that match the four index scores, and the two-factor Verbal and Performance structure was supported in one analysis and rejected in another. Factor analysis groups subtests by how their scores rise and fall together across many people, and each group is called a factor. Confirmatory analysis tests a structure specified in advance and compares how well rival structures fit. Exploratory analysis lets the grouping emerge from the data. The two methods can disagree, and Canivez's review cites a study by Frazier and Youngstrom showing that confirmatory procedures tend to support more factors than common exploratory criteria do, a point that returns in the section on whether the retirement was right.

The supportive reading of the pair comes from Kaufman, Lichtenberger and McLean. They factor analyzed the total WAIS-III sample of 2,450 people aged 16 to 89 using principal factor analysis with two and three factors extracted. They viewed the two-factor solutions as a construct validation of Wechsler's two separate IQs. They also found that the Working Memory subtests tended to load higher on the Performance factor than on their intended scale, which was the Verbal scale. Their coefficients of congruence between like-named factors across different Wechsler batteries consistently exceeded .90 and usually reached .98, so the same pair of factors recurs from one battery to the next. Even this supportive result contains the problem, because working memory subtests that were assigned to the Verbal IQ behaved like part of the other group.

The critical reading comes from García, Ruiz and Abad, who compared several structural models by confirmatory factor analysis in the Spanish standardization sample of the WAIS-III, with 1,369 people. A model with four first-order factors, which they named Verbal, Perceptual Organisation, Working Memory and Processing Speed, had the best fit in every age group and in the total sample. The models with one, two and three factors fit worse, and for them the RMSEA fit index was always above .1, a value usually read as unacceptable. In a hierarchical analysis a general factor accounted for about 58 percent of the variance, while the four group factors together accounted for about 14 percent. The authors concluded that the Verbal and Performance IQs do not seem to make sense, because the two-factor model does not fit the data well. The same paper cautions that the four indexes are themselves strongly influenced by the general factor.

These two papers do not contradict each other as much as they first appear to. Both find that the four index scores correspond to real clusters of subtests, and both find working memory subtests behaving differently from the other verbal subtests. They differ on whether a two-factor description is adequate: one analysis, exploratory and run on the total WAIS-III sample, called it a validation of Wechsler's design, and the other, confirmatory and run on a Spanish adaptation, called it a poor fit compared with four factors. Neither is the last word, and the later work on the WAIS-IV shows that the four-factor structure is not the last word either.

What the analyses do agree on is the point Wechsler made in 1944 from a different direction. A large general factor runs through every subtest, so the two halves are not independent abilities. The page on what IQ measures describes that general factor and the broad abilities below it, and the page on the CHC model gives the names used for those broad abilities in current practice.

6 Why Did the WAIS-IV Stop Reporting Verbal IQ and Performance IQ?

The reasons on the record are practical and structural, and no single source that this page could open gives one stated reason for the adult scale, so the answer is a set of documented strands and not a quotation. The WAIS-IV technical and interpretive manual is a commercial publication that this page did not have, and so it reports what appears in Pearson's published materials, in independent reviews and in the technical report for the children's version.

The first strand is the cleaner summary. For the WISC-IV, the Pearson technical report states that eliminating the dual structure reduced concerns about the influence of working memory and processing speed when summarizing verbal comprehension and perceptual reasoning abilities. The same report says the WISC-IV Full Scale IQ includes more of the influence of working memory and processing speed than its predecessor did, to reflect research suggesting that both are important contributors to overall intellectual functioning. The adult scale made the same pair of moves. According to the Pearson product page for the WAIS-IV, read on October 13, 2026, the WAIS-IV Full Scale IQ uses all ten core subtests and increases the contribution of processing speed, because Coding and Symbol Search are both core subtests.

The second strand is the number of subtests. The same Pearson page acknowledges that the Verbal Comprehension Index and the Perceptual Reasoning Index come from fewer subtests, three each, than the WAIS-III Verbal IQ and Performance IQ, which used six and five. It states that their reliabilities are nonetheless comparable to or higher than those of the old scores. Reliability here means the consistency of a score, and the page on reliability and validity explains how it is judged. Dropping subtests from a composite normally lowers reliability, so the claim that three subtests do as well as six rests on the three being more homogeneous, which fits the idea that the old scores mixed domains. That is our reading of the claim and not a statement Pearson makes.

The third strand is the subtests themselves. Canivez's review lists the goals the manual gave for the revision: updating theoretical foundations, increasing developmental appropriateness, increasing user-friendliness, enhancing clinical utility and improving psychometric features. It records that Object Assembly and Picture Arrangement were dropped, which left Block Design as the one remaining subtest with manipulative objects, and that Visual Puzzles, Figure Weights and Cancellation were added. It adds that the content and structure of the WAIS-IV are explicitly related to current conceptions of intelligence in the work of Carroll, Cattell and Horn, with reference to the hierarchical nature of intellectual measurement. A scale built around that theory has no natural place for a score defined by the format of the task.

The fourth strand is the factor evidence reviewed above, with its own caveats. Canivez notes that the technical manual presents confirmatory analyses only, and that the proportions of variance explained by the general factor and by each first-order factor are absent from it. Nelson, Canivez and Watkins describe the replacement of the Verbal IQ and Performance IQ by the Verbal Comprehension Index and the Perceptual Reasoning Index as among the most substantive changes to the core battery, and they warn that changes this large may mean the new test measures different constructs than its predecessor. That warning is the basis for the next sections, which compare what the old and new scores contain.

7 What Do the WISC-IV, WAIS-IV and WAIS-5 Report Instead?

The current Wechsler adult scales report a Full Scale IQ and a set of index scores, each tied to a cognitive domain, and none of them reports a Verbal IQ or a Performance IQ. The table lays out what each edition printed, using only the documents cited in the last column.

The WAIS-IV is the hinge. Canivez's review lists 15 subtests, 10 of them core. The Verbal Comprehension Index and the Perceptual Reasoning Index are each built from three subtests, and the Working Memory Index and the Processing Speed Index from two each. Supplemental subtests exist for each index, two of them for the Perceptual Reasoning Index. The General Ability Index uses the six verbal comprehension and perceptual reasoning subtests and leaves out working memory and processing speed, so it can be useful when the Full Scale IQ is pulled by those two. Indexes and the Full Scale IQ sit on a scale with an average of 100 and a standard deviation of 15, according to the review. The page on the WAIS-IV goes through the subtests, and the page on the General Ability Index explains the pairing.

The WAIS-5 goes one step further. Pearson's overview brochure gives a publication date of 2024, an age range of 16 through 90 years and 11 months, and a primary battery of ten subtests that appraise five domains: verbal comprehension, visual spatial, fluid reasoning, working memory and processing speed. The old Performance IQ family therefore now spreads over two primary indexes. Pearson's ancillary index flyer lists Block Design and Visual Puzzles under an expanded visual spatial index, and Matrix Reasoning and Figure Weights under an expanded fluid index. Pearson's comparison flyer gives the Full Scale IQ as seven subtests and the primary index scores as five, against four on the WAIS-IV. The pages on the WAIS-5, its subtests and how it differs from the WAIS-IV cover the details.

One WAIS-5 ancillary score deserves a note because it can look like the Performance IQ returning. Pearson lists a Nonverbal Index among its ancillary scores, and the comparison flyer describes it as being for examinees with expressive language difficulties, alongside a Nonmotor Index and a Motor Reduced Processing Speed Index for motor difficulties. The brochure describes these scores as measures of ability not confounded by expressive language or motor problems. This is the use Wechsler had in mind in 1944 when he wrote that one half of the scale could be better for a person with a language or motor handicap. It is not the same thing as a Performance IQ, because it is an optional score for particular circumstances and not one of two routine halves of every report.

Read as a sequence, the editions show a steady move away from format and toward domain. The Verbal IQ and Performance IQ named how a task was answered, and the index scores name what the task is thought to measure. The five WAIS-5 domains line up closely with the broad abilities in the CHC model, and the page on cognitive domains in IQ testing lists them with the subtests that sample them.

8 How Should You Read an Old Verbal IQ and Performance IQ Today?

Read an old Verbal IQ as a related score to the Verbal Comprehension Index and an old Performance IQ as a related score to the Perceptual Reasoning Index, never as the same number, and use the index pages of the old report before the summary page. The Pearson product page for the WAIS-IV, read on October 13, 2026, quotes the WAIS-IV Administration and Scoring Manual, page 5, which says that the terms VCI and PRI should be substituted for the terms VIQ and PIQ in clinical decision making and in other situations where the old scores were used. That is the publisher's own instruction, and it is the nearest thing to an official translation. It is a statement about which term replaces which, and not a conversion formula.

The table sets the old scores beside their nearest current counterparts and states what differs.

Three habits keep the reading honest. The first is to find the edition and the year of testing, which are printed on the first page, because every comparison depends on them. The second is to read the index section of an older report, where the four index scores sit, because a WAIS-III report that printed those four already contains scores that carry the current names. The third is to avoid converting. This page found no official conversion table between the old pair and the new indexes in the sources it opened. Any figure presented as a conversion is an estimate whose error is not published, and the page on how IQ scores are normed shows why scores on different norms do not map one to one.

If the purpose of reading the report is a decision, such as a school, work or legal question, the person making the decision decides which scores count, not the reader. The page on who can administer an IQ test explains who is qualified to interpret a Wechsler report, and the page on adult IQ testing describes how a current evaluation runs. For the question of how large a Verbal IQ and Performance IQ difference is unusual, the sibling page on index score differences gives the current base rates, and this page does not repeat them.

9 Does a Score From an Old Report Carry Forward to a Current Test?

A score from an old report does not carry forward as a number, because the new test has different subtests, different weights and newer norms that are slightly harder. Pearson's WAIS-IV product page makes the point for the move from the WAIS-III. It says the norms of the newer test are slightly harder because of the Flynn effect, and it attributes differences between the two Full Scale IQs to the difference in core subtests. It adds that about 2 percent of examinees are identified as gifted by Full Scale IQ on each edition, but that the same examinees may not be identified, because of the shift in the conceptualization of intelligence.

The Flynn effect is the rise in IQ scores over time that makes older norms easier. Trahan, Stuebing, Fletcher and Hiscock pooled 285 studies with 14,031 people since 1951 and found a meta-analytic mean gain of 2.31 standard score points per decade. For 53 comparisons involving modern Stanford-Binet and Wechsler tests, with 3,951 people, the mean was 2.93 points per decade. The WAIS-III and the WAIS-IV were published about a decade apart, 1997 and 2008. At that rate a person scored against the older norms would be expected to come out a few points higher than against the newer ones, an inference that is our arithmetic on a published rate and not a figure from either manual. The page on the Flynn effect goes through the evidence and its limits, and the sibling page on how IQ tests are made describes how a test is developed and normed, which is where norm age begins.

Four other reasons keep an old Full Scale IQ from being compared directly with a new one.

1. The composition changed. The WAIS-IV Full Scale IQ uses ten core subtests and, according to Pearson, increases the contribution of processing speed, and the WAIS-5 Full Scale IQ uses seven subtests.
2. Practice changes scores. In the WAIS-IV retest sample that Canivez summarizes, 298 people retested after 8 to 82 days, with a mean of 22 days, scored higher the second time, and the gains were greatest on the perceptual reasoning subtests, Block Design, Visual Puzzles, Figure Weights and Picture Completion.
3. People change. The page on how IQ changes with age separates the changes in what a test measures from the changes in the person.
4. Measurement error. Every score has a confidence interval, and the page on reliability and validity explains why two scores a few points apart are not different in any dependable sense.

The same reasoning applies in reverse. A Verbal IQ of 110 from the 1990s and a Verbal Comprehension Index of 110 from last year are two different numbers that happen to match, and a decision should not treat them as a measurement of change. When a current score is needed, the professional route is to retest on a current edition, as the testing standards discussed near the end of this page say.

10 How Do the Old Two Scores Map Onto the Six ACIS Indices?

ACIS reports no Verbal IQ and no Performance IQ, and it sorts the same kinds of task by the ability they draw on, into six primary indices and a Full Scale IQ. We sell a paid assessment, so treat this section as a disclosure and check it against the rest of the page. The mapping below is by ability and not by format, and it is a guide to which index a familiar task type would feed, never a conversion of one score into another.

The grouping resembles what independent analysts found when they re-examined the WAIS-IV. Benson, Hulac and Kranzler reported that a structure inspired by the Cattell-Horn-Carroll theory described test performance better than the published scoring structure did, with crystallized ability, fluid reasoning, visual processing, short-term memory and processing speed, plus a measure of quantitative reasoning. The page on the CHC model explains those abilities, and the page on what each subtest measures lists the tasks.

Three consequences follow for a reader holding an old report. An ACIS Verbal Comprehension Index is not a WAIS Verbal IQ, because it draws on five verbal knowledge subtests and none of the working memory or arithmetic content the old score carried. A strong Performance IQ would show up in ACIS as separate fluid reasoning, visual spatial and processing speed indices, which can differ from each other. And an ACIS report does not replace a Wechsler evaluation.

The limits matter as much as the design. ACIS is online and unsupervised, it is not a clinical or diagnostic instrument, it is not for hiring, school accommodations or admission to high IQ societies, and it is offered in English only. The report gives indices and the Full Scale IQ on the standard scale with an average of 100 and a standard deviation of 15, scaled subtest scores from 1 to 19 with an average of 10 and a standard deviation of 3, a percentile for each score and a 95 percent confidence interval, against adult norms for ages 16 to 90. The technical manual documents the instrument, and the page on professional and online tests compares what each can support.

The prices below were read on the ACIS home page on October 13, 2026 and can change. All are one time payments with no subscription. Quick is 15 dollars for 6 subtests in 3 domains and takes about 45 minutes. Optimized is 30 dollars for 13 subtests in 5 domains and takes about 110 minutes. Full Scale is 50 dollars for all 20 subtests in six domains and takes about 175 minutes. Breaks are allowed, the free trial needs no card, there is a 5 day quality guarantee, and a purchased form can be completed within 30 days. A Quick form samples only three domains, so it cannot produce all six indices.

11 Was Dropping the Two Scores the Right Call?

The evidence supports retiring the Verbal IQ and Performance IQ as a description of the WAIS-III data, and it does not show that the four index scores that replaced them are the final units either. The studies below ask the same question of both structures.

The argument for the change is that the old pair mixed domains, that the confirmatory test of the WAIS-III reviewed here found four factors fit better than two, and that the publisher reports the replacement indexes as reliable. The argument for caution is in Canivez's review: confirmatory analysis supports a theoretical structure but cannot be applied directly in clinical interpretation, and the manual omitted the variance proportions and subtest specificity that a clinician needs to judge how much an index adds.

Canivez and Watkins then supplied some of those proportions and concluded that the WAIS-IV measures general intelligence strongly and that clinical interpretation should be primarily at that level. Nelson, Canivez and Watkins found that the Full Scale IQ accounted for medium to large portions of academic achievement variance in a clinic sample, and that the four factors combined added significant variance beyond it, but that no single index added more than a trivial amount. That is a finding about achievement in referred people and does not generalize to every purpose.

Taken together, the sources do not say the old scores should have stayed, and they do not say the new indexes are the best possible units. They say that a general factor dominates, that subscores add little beyond it in the cases studied, and that the structure below it depends on method. The WAIS-5 splitting visual spatial and fluid reasoning, the CHC-style reading of Benson and colleagues, and the six ACIS indices all point in the same direction, toward domains named for abilities. The page on the g factor describes why one number carries so much of the variance.

12 What Do the Testing Standards Say About Reading an Old Score?

The Standards for Educational and Psychological Testing (AERA, APA and NCME, 2014) ask for evidence behind any interpretation of subscores and score differences, and they warn against relying on outdated scores, which is the situation of anyone reading a Verbal IQ and a Performance IQ from the 1990s. The Standards are published jointly by the American Educational Research Association, the American Psychological Association and the National Council on Measurement in Education. Standard 1.13 asks for evidence about the internal structure of a test when an interpretation depends on relationships among its parts. Standard 1.14 asks that when interpretation of subscores, score differences or profiles is suggested, the rationale and evidence be given, and its comment adds that evidence for two separate scores would not necessarily justify interpreting the difference between them. A Verbal IQ minus Performance IQ gap is exactly such a difference.

The Standards also address age. They say tests should be reviewed periodically and revised when content or language has become outdated, and they note that outdated norms need not carry the same implication as outdated content. In the chapter on psychological testing and assessment, they say that for a test that has been revised, the edition currently supported by the publisher usually should be selected, that an earlier edition is occasionally appropriate, for example in longitudinal research or when it holds subtests a later one lacks, and that professionals must guard against reliance on outdated scores, for which retesting is appropriate. A comment to Standard 6.14 says outdated scores should generally not be used except for research, although scores from past years can be useful for longitudinal assessment.

The American Psychological Association's Ethical Principles of Psychologists and Code of Conduct points the same way. Standard 9.08 asks psychologists not to base assessment or intervention decisions or recommendations on data or test results that are outdated for the current purpose. These are rules for professionals and not for the person reading a report at home, but they set the standard a reader can fairly expect.

Five questions turn those rules into a practical check on an old Verbal IQ and Performance IQ.

1. Which edition and year produced the scores, and is a current edition available?
2. Does the report print the index scores as well, and what are they?
3. How common is a gap of this size in the norm group, according to the manual?
4. For what purpose will the old scores be used, and is that purpose better served by a current score?
5. Who is qualified to interpret the report for that purpose?

None of this makes the old report worthless. It remains an accurate record of how one person performed on one test on one day, against that edition's norms. The mistake lies in treating either number as a current, interchangeable measure, or in reading a gap between them as a statement about the person.

13 Sources Behind This Page

Every figure and attribution on this page traces to one of the sources below, or is labeled as our own arithmetic or rounding. The two exceptions are the rounding of the general factor shares reported in the Spanish WAIS-III study to about 58 and 14 percent, and the inference that a decade of the Flynn effect implies a few points, which is our arithmetic on a published rate. Pearson pages were read on October 13, 2026 and can change. The WAIS-IV technical and interpretive manual was not available to this page, so statements about it come from the review and the Pearson page cited.

• Wechsler D. The Measurement of Adult Intelligence, third edition. Williams and Wilkins, Baltimore, 1944, pages 11, 12 and 136 to 138, and tables of verbal and performance subtests.
• Boake C. From the Binet-Simon to the Wechsler-Bellevue: Tracing the history of intelligence testing. Journal of Clinical and Experimental Neuropsychology, 2002, volume 24, issue 3, pages 383 to 405.
• Kaufman A S, Lichtenberger E O and McLean J E. Two- and three-factor solutions of the WAIS-III. Assessment, 2001, volume 8, issue 3, pages 267 to 280.
• García L F, Ruiz M A and Abad F J. Factor structure of the Spanish WAIS-III. Psicothema, 2003, volume 15, issue 1, pages 155 to 160.
• Canivez G L. Review of the Wechsler Adult Intelligence Scale, Fourth Edition. Buros Mental Measurements Yearbook, 2010, entry 151, beginning on page 684.
• Canivez G L and Watkins M W. Investigation of the factor structure of the Wechsler Adult Intelligence Scale, Fourth Edition (WAIS-IV): Exploratory and higher order factor analyses. Psychological Assessment, 2010, volume 22, issue 4, pages 827 to 836.
• Nelson J M, Canivez G L and Watkins M W. Structural and incremental validity of the Wechsler Adult Intelligence Scale, Fourth Edition with a clinical sample. Psychological Assessment, 2013, volume 25, issue 2, pages 618 to 630.
• Benson N, Hulac D M and Kranzler J H. Independent examination of the Wechsler Adult Intelligence Scale, Fourth Edition (WAIS-IV): What does the WAIS-IV measure? Psychological Assessment, 2010, volume 22, issue 1, pages 121 to 130.
• Trahan L H, Stuebing K K, Fletcher J M and Hiscock M. The Flynn effect: A meta-analysis. Psychological Bulletin, 2014, volume 140, issue 5, pages 1332 to 1360.
• Pearson. Wechsler Adult Intelligence Scale, Fourth Edition, product page and frequently asked questions, publication date 2008, read October 13, 2026.
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14 Frequently Asked Questions