The IQ test for former gifted kids: why your not your number now

0 The short answer

A childhood gifted score was one measurement from one day on one test with that test's norms, so it should be read as good evidence about where you ranked then and as a rough forecast of where you rank now, not as your current number. Rank order is fairly stable, but it is not fixed: in the best known follow-up, scores at age 11 and age 77 correlated .63, and any group selected for a high score will, on average, score lower the next time. A new adult score from a test normed on adults is the only way to replace the forecast with a measurement, and the right test depends on whether you need a certificate (Mensa or a psychologist) or an understanding of your own profile.

1 What Did Being Labeled "Gifted" Actually Record About You?

A gifted label is an administrative decision made by a school or district, usually from one or more test scores plus other information, and it records a status at one age more than it records a number you can carry into adulthood. The National Association for Gifted Children, in its page on assessments and tests (copyright 2026, read on October 13, 2026), says tests are common tools for identification but should not be the sole source, recommends combining objective and subjective assessments, and says each district or school sets its own program criteria. That one sentence explains why two children with the same label can hold very different records. One may have been placed on a group screening score in second grade, another on an individual test given by a school psychologist, another on a teacher nomination backed by grades.

The scientific definition is just as loose. Subotnik, Olszewski-Kubilius and Worrell (2011), in a monograph for Psychological Science in the Public Interest, review how giftedness is defined and conclude that definitions of giftedness are not standardized. Their own proposal treats giftedness as developmental: in the early stages, potential is the key variable, and in later stages achievement becomes the measure. In their words, giftedness is "typically manifested in actual outcomes, especially in adulthood," which is a reminder that the childhood label was a prediction about the future, not a trophy for the past.

So the first practical step is to work out what your record actually says. Four questions sort it:

1. Was there a test score at all, or only a program placement? Many people remember "I was in the gifted program" and nothing else.
2. If there was a score, was it an IQ-type score, a percentile, or a school achievement score? Mensa, for example, says almost any test with "achievement" in the title is not acceptable for admission.
3. What was the test called and how old were you? A group screening test given in a classroom and an individual test given by a psychologist are different instruments even when both produced the word "gifted."
4. Who holds the paperwork now: you, your parents, a school district or a psychologist's file?

If you can answer the third question, you can do most of what the rest of this page describes. If you cannot, the label still tells you something real, namely that adults who knew you in childhood judged your performance to be well above your peers. It does not tell you a number, and the sections below explain why a number from that era should not be treated as your present IQ even when you do have one. The neighbouring page on gifted testing for adults who were never formally assessed covers the opposite situation, the adult who never had a record, and does not need to be repeated here.

2 Why Did the Same "Top Two Percent" Carry Different Numbers on Different Tests?

The same rarity is written as different numbers on different tests, so "my childhood score was 132" and "my childhood score was 130" can describe the same standing, and neither can be compared with an adult score without knowing the test. American Mensa's page of qualifying test scores, which we read on October 13, 2026, shows this plainly. The society requires a score in the top 2 percent, and its table lists a separate cutoff for each test:

The CogAT is filed on that page among the school district tests, and the Stanford-Binet appears in both the school district and the private psychologist tables. The page says the list is not complete. It also says Mensa does not accept blended scores or scores from more than one test administration, and that the Wechsler tests must be given in their entirety. Our reading is that the scales are not identical, so the same percentile lands on different numbers, which is the reason the society publishes one threshold per test rather than one number. The page on how IQ scores are normed and the page on why a 15 point standard deviation matters explain how a percentile becomes a score on a given scale, and the percentile converter lets you do the conversion yourself.

The practical consequence is that a remembered number is incomplete without three facts: the test, the scale and the date. A 130 on a group test of nonverbal reasoning and a 130 Full Scale IQ on an individual Wechsler test are not the same measurement. The Wechsler Full Scale in its fifth children's edition rests on seven subtests, which Pearson's product page for the WISC-V (read October 13, 2026) lists as Similarities, Vocabulary, Block Design, Matrix Reasoning, Figure Weights, Digit Span and Coding. A nonverbal group screening test samples a narrower slice of ability. Both can place a child in the top few percent, and both can be right about that, while saying different things about verbal knowledge, working memory and speed.

The threshold itself also varied by program. NAGC states that program criteria are left to the district or the school, and the page on the gifted IQ range covers the 130 threshold, about the 98th percentile, even though a school could have chosen another cutoff. If your memory is "I was in the top 5 percent," you are describing a different line than "I scored 130," and a new adult score will not map onto either one without conversion.

3 How Stable Is IQ From Childhood to Adulthood?

Rank order on intelligence tests is fairly stable from adolescence onward and much less stable from early childhood, and even the best long-run correlations leave room for large differences in an individual's score. The most complete summary is a meta-analysis by Breit, Scherrer, Tucker-Drob and Preckel (2024) in Psychological Bulletin. It pooled 205 longitudinal studies with 87,408 participants and 1,288 test-retest correlations. For a sample age of 20 and a test-retest interval of 5 years, the mean rank-order stability was .76. Stability rose rapidly through childhood and was consistently high from late adolescence to late adulthood, was low in preschool children, and fell as the interval grew, with the decline flattening from roughly 5 years onward. The authors also report that a stability of .80, which they treat as the minimum sufficient for individual-level diagnostic decisions, can only be expected over age 7 and for short intervals in children.

That last point matters for a former gifted child. If your identification came in the early school years, it fell on the part of the curve where stability is still rising. That does not make early scores useless, but it means they carry more error as predictors of a score decades later than a test taken in the late teens does.

The longest follow-ups use the same test twice. Deary, Whalley, Lemmon, Crawford and Starr (2000) in Intelligence describe the 1932 Scottish Mental Survey, in which all Scottish children born in 1921 and attending school on June 1, 1932 (N = 87,498) took the Moray House Test. The team re-administered the same test to 101 of these people at age 77. The correlation between the two sittings was .63, or .73 when corrected for the narrower range of ability in the retested sample, and the authors called it the longest follow-up of psychometric intelligence reported to that date. A later follow-up of the same survey, by Deary, Pattie and Starr (2013) in Psychological Science, retested 106 members of the Lothian Birth Cohort of 1921 at age 90 and found a correlation of .54, or .67 corrected for range restriction.

Deary and colleagues (2000) also tabulate earlier studies in their Table 1. For one Stanford-Binet follow-up, they list a correlation of .41 between a mean initial age of 4 and a mean follow-up age of 42, and .68 between an initial age of 14 and the same follow-up at 42. In that study, the older the child at first testing, the better the early score predicted the later one.

A correlation is not an individual forecast. Squaring .63 gives about .40, which is our arithmetic and is the share of variation in the later score that can be linked to the earlier one in a simple linear model. The rest is something else: measurement error, real change, differences between the two tests and the narrowed range in a retested sample. This is why the findings sit comfortably with two statements that sound contradictory. Childhood ability does predict adult ability, and a given person's adult score can differ from the childhood score by a lot. The page on how IQ changes with age separates stability of rank from change in raw performance, and the page on what an IQ test actually measures sets the scores in context.

4 Why Is a High Childhood Score Likely to Come Down on Retest?

Because children were selected for gifted programs on a high score, and any score selected for being high contains some luck that does not repeat, so on average the next score is lower even if nothing about the child changed. This is regression to the mean. Barnett, van der Pols and Dobson (2005), writing for epidemiologists in the International Journal of Epidemiology, define it as a statistical phenomenon that makes natural variation in repeated data look like real change, because unusually large or small measurements tend to be followed by measurements closer to the mean. The effect becomes more noticeable as measurement error rises and when follow-up is examined only on a subsample selected by its baseline value, which is exactly what a gifted program is.

The gifted-education literature has measured the size of this effect. Lohman and Korb (2006), in Journal for the Education of the Gifted, analyzed longitudinal changes in ability and achievement test scores through elementary school. Their abstract reports that the majority of children who score in the top few percentiles on ability and achievement tests in one grade do not retain their status for more than a year or two, and that year-to-year regression is substantial even for highly reliable scores. They name four causes: errors of measurement, individual differences in growth, changes in the content of the developmental score scale, and changes in the norming population across ages or grades. The abstract adds that combining ability and achievement scores in different ways can reduce regression, and discusses what that means for selection.

Two lessons follow. First, "gifted today but not tomorrow" is a property of selecting on one score, not a verdict on any child. Second, the same logic applies in the opposite direction to a retest in adulthood. A former gifted child who retests as an adult is, on average, expected to land closer to 100 than the childhood score was, and that shift should not be interpreted as loss.

The size of the expected shift can be worked out with the textbook regression formula. The table below is our arithmetic and is illustrative only: it assumes both scores are on the same scale with a mean of 100 and a standard deviation of 15, a linear relationship, and no difference in norms or test content. The expected adult score is 100 plus r times the childhood deviation from 100, and the typical spread around it is 15 times the square root of one minus r squared. The correlations are chosen to bracket the published values above (.63 over the 66 years from age 11 to 77, .76 for 5 years at age 20), not taken from a single study.

Read the table as a description of how groups behave, not as a prediction for you. A person who scored 130 as a child and sits at 121 on a similar adult test has done nothing unusual. A person at 135 has done nothing unusual either, since about one person in six falls more than one spread above the expected score. The page on how rare a given IQ is shows what those values mean in rarity terms.

5 What Does the Flynn Effect Do to an Old Score?

Raw performance on IQ tests has risen across generations, so a score earned against older norms looks higher than the same performance would against current norms, which pushes a childhood number up relative to a new adult one. Trahan, Stuebing, Fletcher and Hiscock (2014) pooled 285 studies with 14,031 participants in Psychological Bulletin, all of which gave two intelligence tests with different normative bases. The mean rise was 2.31 standard score points per decade, with a 95 percent confidence interval of 1.99 to 2.64. For 53 comparisons involving modern Stanford-Binet and Wechsler tests, the figure was 2.93 points per decade, with an interval of 2.3 to 3.5. For the modern tests, they report that age and ability level were not significant moderators, so the rise was not confined to average scorers or to children.

Pietschnig and Voracek (2015), in Perspectives on Psychological Science, analyzed 271 independent samples totaling almost 4 million participants from 31 countries between 1909 and 2013. They estimated annual gains of 0.41, 0.30, 0.28 and 0.21 IQ points for fluid, spatial, full-scale and crystallized tests respectively, found the gains stronger for adults than for children, and found them decreasing in more recent decades.

For one old score the consequence is modest but one-directional. If a test was normed some years before you sat it, your raw performance was compared with an older and, on average, lower-performing group. Our illustration: at the 2.93 points per decade reported for modern Wechsler and Binet tests, a norm sample collected one decade before the test date would inflate scores by roughly 3 points. That is arithmetic on a group average, not a correction to apply to your number. Trends differ by period, instrument and country.

The page on the Flynn effect and norm obsolescence works through the mechanics, and the page on why a WAIS-IV score drops on the WAIS-5 shows the same effect when an adult instrument is renormed. For this page the important point is narrower: the Flynn effect and regression to the mean act in the same direction on a high childhood score. Neither is evidence that you became less able. Both are reasons the old number overstates a modern adult comparison.

6 Can Two Good Tests Disagree About the Same Person?

Yes, and the gap is often large enough to change a label: Floyd, Clark and Shadish estimated that about one in four people taking one intelligence battery would score more than 10 points higher or lower on a different battery. The finding comes from the abstract of their article, "The exchangeability of IQs," published in Professional Psychology: Research and Practice (2008). They concluded that different batteries yield less similar IQs for school-age children and undergraduates than many psychologists assume, and recommended considering multiple IQ scores when results drive high-stakes decisions.

Several ordinary reasons explain this without any test being wrong. The batteries sample different abilities, so a child strong in one domain scores differently on a test that weights it more. The norms were collected in different years and on different samples, which brings the Flynn effect in. Each score has its own measurement error, and each sitting has its own conditions of mood, sleep, motivation and examiner. And a group screening test and an individual clinical test are different procedures in the first place.

For a former gifted child the risk is of a false story. If a childhood score of 140 on one test is followed by an adult score of 125 on another, it is tempting to conclude something happened between the two. The more likely reading, given regression, norm years and test differences, is that both scores are reasonable measurements of a person who is well above average, which is the substantive claim. The page on the difference between a professional and an online IQ test explains what each kind of score can support.

Ceilings are a separate problem that affects the youngest identifications in particular. Subotnik and colleagues (2011) list test ceilings that are too low to measure progress or growth among the methodological challenges of studying gifted populations, and NAGC says assessments used for identification should not have a ceiling. A child who tops out on a test cannot be distinguished from a child who would have scored higher on a harder one, so a childhood number at the top of a scale may be a floor on the child's ability rather than an estimate of it. That feature of old records is another reason not to read a childhood score as a point.

7 What Does a Six-Index Report Show That a Single Childhood Number Did Not?

A report that gives indices for separate abilities lets you see which parts of the childhood label still show and which do not, which a single composite cannot. The Full Scale IQ is an average over abilities, and two people can share the same composite with different shapes. The page on the Full Scale IQ explains how the composite is formed, and the page on the general ability index shows how professionals handle profiles that are uneven.

ACIS reports six primary indices in six Cattell-Horn-Carroll (CHC) domains: verbal comprehension (VCI, Gc), fluid reasoning (FRI, Gf), quantitative reasoning (QRI, Gq), visual spatial (VSI, Gv), working memory (WMI, Gwm) and processing speed (PSI, Gs). The full form administers all 20 subtests. The page on the CHC model defines the domains, and the page on what each subtest measures names the tasks without reproducing any item. For a former gifted kid, three features of this structure matter.

First, many childhood identifications leaned on one kind of ability, often verbal or nonverbal reasoning, because that is what a classroom screening test sampled. An adult profile shows whether your standing was broad or concentrated, which the label could not say.

Second, a profile lets you see what a screening test could not. A test that samples one kind of reasoning says little about spatial ability, memory or speed. The point is that a composite hides what a profile shows.

Third, a profile gives you a better comparison with your history. If your memory is "I was always the verbal one," an adult verbal index tells you whether that still stands. If your childhood placement came from a nonverbal reasoning test, the fluid reasoning index is the closest conceptual match, and the other five indices are new information rather than a replication. None of this settles what your number should be. It gives you more than one number to compare.

8 Can Your Childhood Score Still Be Used, and Where Might It Be Kept?

A childhood score can still do one concrete job today, which is to qualify you for a high IQ society if the test is on the society's list and you can document it, and it can do nothing else as a current measurement. American Mensa's page on joining with past test scores, which we read on October 13, 2026, says it accepts scores from approximately 150 different standardized intelligence tests, though its list is not complete, and that scores are acceptable forever so long as they meet the admission requirements. The date that counts is the date you took the test, not the date you join. The page also lists the limits: unsupervised and internet-based tests are not accepted, nor are blended scores or scores from more than one administration, and almost any test with "achievement" in the title is out.

The documentation rules matter more than the score for most people. The page requires the original or a notarized copy of the original, and the name on the paper must match the name on the application. Scores from a school need a sealed transcript or a signed school document on letterhead. Reports from a clinic or private psychologist must show the test name, the score and the percentile rank on letterhead, signed by the psychologist and including the psychologist's state license number. American Mensa's join page, read the same day, lists the criterion as a score in the top 2 percent and names the SAT, the Stanford-Binet and the CogAT among the prior scores people submit, with annual dues of 107 dollars. Neither page lists a fee for evaluating prior scores, so ask before you pay anything for that step.

Whether you can produce the paper is a separate question. The Standards for Educational and Psychological Testing (AERA, APA and NCME, 2014) say in the comment to Standard 6.14 that organizations holding identifiable test scores should set guidelines for how long records are retained, and that in some instances scores become obsolete and no longer reflect the current state of the test taker. Retention is therefore the holder's policy, not a guarantee. Practical places to ask are the school district's records or gifted program office, the psychologist or clinic that tested you, and your parents' files. If a document exists, ask for the full report rather than a letter, since Mensa wants the test name, score and percentile rank in writing.

Even a perfectly documented score does not become a current measurement. The same Standards state, in the chapter on the rights and responsibilities of test users, that professionals are responsible for guarding against reliance on test scores that are outdated, and that retesting is appropriate in such cases. In the chapter on psychological testing and assessment they note that scores for young adults or children on cognitive measures may change in later years, so users should be cautious about over-reliance on results that may be outdated. A document from age 9 can open a society's door and, at the same moment, be the wrong basis for a decision about who you are at 29. The page on high IQ society requirements and the page on qualifying for Mensa cover the society routes in detail, and the page on why no institution accepts an IQ certificate explains why an online score cannot replace the paper.

9 Which Adult Assessments Exist for Someone With an Old Gifted Score, and What Does Each Cost?

An adult has five realistic routes, a prior-evidence submission, a supervised society test, a psychologist, a normed online test and a free screener, and the right one depends on whether anyone other than you needs to be persuaded. That is the test our guide to the adult assessment process uses: if somebody else needs to accept the result, you need the formal route, and if not, you need a good instrument and an honest report. The table sets out what each route is, what it cost where we could read a price on October 13, 2026, and what it cannot do. Prices change and promotional prices expire, so confirm before buying.

The Mensa figures come from American Mensa's testing page, read October 13, 2026, which also says photo identification with proof of date of birth is required, that testing is not offered under age 14, and that a person can take a test or battery once every eight weeks. The clinic row is one clinic's published fee for one kind of evaluation, from the Psychological Services Center at the University of South Florida. It is an example of what training clinics charge, not a national price, and the same page lists other evaluations at higher fees. The private psychologist row is our guide's own general statement, so we treat it as an orientation, not a quote.

Which should a former gifted kid choose? Three questions settle it. If your only goal is a Mensa card and you hold a qualifying score, submit the evidence and skip the test. If you need a document a school, an employer or a court will accept, a licensed psychologist is the only route, and the page on who can administer an IQ test explains why. If you want to know where you stand now and how your abilities are shaped, a normed profile is the most efficient answer, and it can be followed by a professional evaluation later if the result raises a question you need answered formally. The page on where to take an IQ test lists every route side by side, and the page on what an IQ test costs gives a longer price breakdown. The page on free and validated tests explains why the last row of the table deserves no weight when you are replacing an old number with a new one.

10 How Do You Read a New Number Against an Old One?

Compare percentiles, not points, name the test and the date on both sides, add the expected regression, and treat any single gap as a feature of two measurements rather than as news about you. Six steps do most of the work.

1. Name both tests. Write down the childhood test, your age, the year, and the adult test. If you cannot name the childhood test, you can still compare standing, but not scores.
2. Convert both to percentiles. A score on one scale is not a score on another, as the Mensa table shows. The page on the difference between a score and a percentile explains why points should not be compared across tests directly, and the converter linked earlier does the arithmetic. For example, a Full Scale IQ of 130 on a scale with a mean of 100 and a standard deviation of 15 is about the 98th percentile, and 121 is about the 92nd, which is our arithmetic on the normal curve.
3. Add the expected drift. Use the regression table above. From a childhood 130, an adult 121 is the expected average, and a spread of roughly 10 to 12 points around it is ordinary.
4. Allow for norm years. If the childhood test was normed years before you sat it, expect a few points of inflation on average, as the Flynn section describes. The point is the direction, not a precise correction.
5. Look at the interval. A single adult score is an estimate with a range around it. The report should print a confidence interval, and Standard 2.13 of the Standards says the standard error of measurement should be provided in units of each reported score, which is what lets a reader see how wide the range is.
6. Compare shape, not just height. If your adult profile is uneven, the Full Scale IQ is the least informative figure on the page. Reading the indices side by side, before the composite, is how a profile is understood.

What can the gap tell you? The table gives a cautious reading, based on the group evidence above rather than on any individual. It makes no clinical claim.

The same logic applies to your own remembered number. If you recall "I was 148," ask what test, how old you were and whether that was an IQ or a percentile, since a remembered figure is itself a measurement made by memory. The page on what your IQ number means has a section on childhood scores, norm years and age tables that sets the same principles in a wider frame.

11 What Does a Lower or a Higher Number Say About You Now?

It says where your measured ability ranks among adults on one test on one occasion, and it does not say whether the childhood label was right, wasted or earned. NAGC states on its assessments page that assessments provide data points but do not automatically guarantee placement in gifted programs, and that program criteria are set by the district or school. The label was always a decision made from partial evidence by other people, which means an adult number cannot overturn it and cannot confirm it. It can only add a fresh data point from a better-matched instrument.

The research on how giftedness develops points the same way. Subotnik and colleagues (2011) treat giftedness as developmental, with achievement becoming the measure in later stages and psychosocial variables such as motivation, mindset and task commitment playing a determining role in whether talent develops. Their summary lists general and domain-specific ability among the variables most associated with outstanding achievement, next to creativity, passion, opportunity and chance. They conclude that both cognitive and psychosocial variables are malleable. For a reader, that means a score at 30 is one input into a life that was shaped by many others, and a lower number than the one you remember does not set a limit on what you can do.

Group findings do not translate into predictions for individuals, and this page does not claim to assess anyone's state of mind or wellbeing. A question about stress, mood, attention or learning difficulty belongs with a licensed clinician, and an IQ test is not a screening tool for any of those. The page on twice-exceptional adults is the place to read about giftedness alongside a disability. What the number can do, honestly, is replace an old story that began as someone else's decision with a current measurement you can read yourself, with a range around it and a profile behind it. The page on gifted adults covers the research on ability after childhood, including adults who were missed as children, and the page on whether you can raise your IQ covers what training does and does not move.

12 Where ACIS Sits, and What a Buyer Should Do

ACIS is an online, unsupervised, adult-normed profile that gives a Full Scale IQ, six indices and a confidence interval, but it is not a clinical or diagnostic instrument, it cannot replace the paper a society or a school asks for, and it is in English only. The facts below were read from the ACIS home page on October 13, 2026. ACIS offers three one time forms with no subscription. Quick costs 15 dollars, has 6 subtests in 3 domains and takes about 45 minutes. Optimized costs 30 dollars, has 13 subtests in 5 domains and takes about 110 minutes. Full Scale costs 50 dollars, has all 20 subtests in six domains and takes about 175 minutes. Breaks are allowed, you have 30 days to complete the test, the free trial needs no card, and there is a 5 day quality guarantee. Prices can change. Indices and the Full Scale IQ are reported on the standard scale (mean 100, standard deviation 15), subtest scores run from 1 to 19 with a mean of 10 and a standard deviation of 3, and the report gives percentiles and a 95 percent confidence interval. Adult norms cover ages 16 to 90.

The limits are as plain as the strengths. The test is taken on a screen with no examiner, so no one checks effort, the room or whether someone else is helping. It is not for hiring, school accommodations or admission to high IQ societies, so it cannot replace the prior-evidence paper or the supervised test described above. It is not clinical, so it cannot tell you why you score as you do. It is in English only. The documentation for the scores lives in the technical manual, and this page does not quote figures from it.

The professional standards support reading a report this way. The Standards for Educational and Psychological Testing (AERA, APA and NCME, 2014) ask that test users receive clear explanations of what scale scores mean, what they intend and what their limits are (Standard 5.1), that interpretations given to test takers describe in simple language what the test covers, what scores represent, the precision of the scores and how they are meant to be used (Standard 6.10), and that error be reported in the units of each score (Standard 2.13). They also warn against reliance on outdated scores, as the sections above noted. The American Psychological Association publishes the APA Guidelines for Psychological Assessment and Evaluation (2020) as guidance for clinicians; this page cites it as the professional reference for formal evaluations and does not quote its content.

What should a former gifted kid do? First, find out what your record says: the test, the age, the number, and whether the paper exists. Second, decide the purpose. If you want membership and the old score qualifies, submit it. If someone else must accept the result, book a licensed psychologist. If you want your own current picture, start the free trial, read the subtest pages for the timed tasks, set up a quiet room, and choose the form that includes the domains you care about. The Full Scale form covers all six, and the report's interval and indices matter more than the single number. Third, compare the new profile against the old story using the six steps above, and expect it to differ from the old number in the ways the research predicts. If you were never formally assessed in the first place, the neighbouring page for adults with no record is the better starting point, and if you are still a student, the page on IQ tests for college students covers the situation you are in now.

13 Sources Behind This Page

Every figure and product fact on this page comes from the documents below, verified or read on October 13, 2026, and any figure we derived ourselves is labeled in the text as our arithmetic.

1. American Educational Research Association, American Psychological Association, and National Council on Measurement in Education (2014). Standards for Educational and Psychological Testing. Washington, DC: AERA. Open access edition: https://www.testingstandards.net/open-access-files.html
2. American Psychological Association (2020). APA Guidelines for Psychological Assessment and Evaluation. PsycEXTRA record: https://doi.org/10.1037/e510142020-001
3. Barnett, A. G., van der Pols, J. C., and Dobson, A. J. (2005). Regression to the mean: what it is and how to deal with it. International Journal of Epidemiology, 34(1), 215-220. https://doi.org/10.1093/ije/dyh299
4. Breit, M., Scherrer, V., Tucker-Drob, E. M., and Preckel, F. (2024). The stability of cognitive abilities: A meta-analytic review of longitudinal studies. Psychological Bulletin, 150(4), 399-439. https://doi.org/10.1037/bul0000425
5. Deary, I. J., Whalley, L. J., Lemmon, H., Crawford, J. R., and Starr, J. M. (2000). The stability of individual differences in mental ability from childhood to old age: Follow-up of the 1932 Scottish Mental Survey. Intelligence, 28(1), 49-55. https://doi.org/10.1016/S0160-2896(99)00031-8
6. Deary, I. J., Pattie, A., and Starr, J. M. (2013). The stability of intelligence from age 11 to age 90 years: The Lothian Birth Cohort of 1921. Psychological Science, 24(12), 2361-2368. https://doi.org/10.1177/0956797613486487
7. Floyd, R. G., Clark, M. H., and Shadish, W. R. (2008). The exchangeability of IQs: Implications for professional psychology. Professional Psychology: Research and Practice, 39(4), 414-423. https://doi.org/10.1037/0735-7028.39.4.414
8. Lohman, D. F., and Korb, K. A. (2006). Gifted today but not tomorrow? Longitudinal changes in ability and achievement during elementary school. Journal for the Education of the Gifted, 29(4), 451-484. https://doi.org/10.4219/jeg-2006-245
9. Pietschnig, J., and Voracek, M. (2015). One century of global IQ gains: A formal meta-analysis of the Flynn effect (1909 to 2013). Perspectives on Psychological Science, 10(3), 282-306. https://doi.org/10.1177/1745691615577701
10. Subotnik, R. F., Olszewski-Kubilius, P., and Worrell, F. C. (2011). Rethinking giftedness and gifted education: A proposed direction forward based on psychological science. Psychological Science in the Public Interest, 12(1), 3-54. https://doi.org/10.1177/1529100611418056
11. Trahan, L. H., Stuebing, K. K., Fletcher, J. M., and Hiscock, M. (2014). The Flynn effect: A meta-analysis. Psychological Bulletin, 140(5), 1332-1360. https://doi.org/10.1037/a0037173
12. National Association for Gifted Children. Assessments and Tests, read October 13, 2026. https://www.nagc.org/assessments-and-tests
13. American Mensa. Qualifying Test Scores for Mensa Membership and Join Mensa Using My Past Test Scores, read October 13, 2026. https://www.us.mensa.org/join/testscores/qualifying-test-scores/ and https://www.us.mensa.org/join/testscores/
14. American Mensa. How to Join Mensa and Testing, read October 13, 2026 (criterion, annual dues, test fees, age and identification rules). https://www.us.mensa.org/join/ and https://www.us.mensa.org/join/testing/
15. Pearson Assessments. WISC-V, Wechsler Intelligence Scale for Children, Fifth Edition (product page), read October 13, 2026. https://www.pearsonassessments.com/en-us/Store/Professional-Assessments/Cognition-%26-Neuro/Wechsler-Intelligence-Scale-for-Children-%7C-Fifth-Edition-/p/100000771
16. University of South Florida, Psychological Services Center. Clinic Policies, read October 13, 2026 (page shows no date for the fee list). https://www.usf.edu/arts-sciences/departments/psychology/psychological-services-center/clinic-policies

14 Frequently Asked Questions