Inclusion Now 46

IQ Testing and Disabled Children

“We have to provide an IQ score so that the CAMHS team can allocate their resources. They keep asking us….” (Principal Educational Psychologist – 2008- Unnamed UK Local Authority)

Intelligence testing began in earnest when in 1904 the French government commissioned psychologist Alfred Binet to find a method of differentiating between children who were ‘intellectually normal and those who were inferior’, in order to put the latter into special schools where they would receive more individual attention. In this way the disruption they caused in the education of intellectually normal children could be avoided. Sound familiar?

This was a natural development from Darwinism and the Eugenics movement that dates back to 1869. Sir Francis Galton promoted the idea that for society to prosper the ‘weakest’ should not be allowed to have babies, as this would affect the genetic stock of future generations. He and his many followers were contemptuous of any impact education might have on raising the achievement of the ‘least able’ (Thomas and Loxley, 2007).

Binet’s work led to the development of the Binet Scale, a new approach to assessing mental ability. However, Binet himself cautioned against its misuse or misunderstanding. According to Binet, it was designed only to identify children requiring special education, not as “a general device for ranking all pupils according to mental worth.” Binet noted that “the scale, properly speaking, does not permit the measure of intelligence.”

Since, according to Binet, intelligence could not be described as a single score, the use of the Intelligence Quotient (IQ) (a notion coined by Terman in 1916) as a definite statement of a child’s intellectual capability would be a serious mistake. Binet feared that IQ measurement would be used to condemn a child to a permanent “condition” of stupidity, damaging his or her life chances:

‘Some recent thinkers…[affirm] that an individual’s intelligence is a fixed quantity, a quantity that cannot be increased. We must protest and react against this brutal pessimism; we must try to demonstrate that it is founded on nothing.’ (Binet)

Binet’s scale had a profound impact on educational development. However, the educators and psychologists who championed the scale and its revisions failed to heed Binet’s caveats.
Cyril Burt, the first educational psychologist for London in 1913, was less cautious than Binet. A Social Darwinist, he was convinced of the inherited basis of intelligence and fond of psychometrics. This gave great impetus to segregated education based on categorisation of children. Burt’s reputation is now linked to his fraudulent invention of data about inherited intelligence based on non-existent twin studies but at the time his influence was enormous.

When medical officers were largely responsible for selecting pupils for UK special schools the most important item in the selection process was the Stanford-Binet Intelligence Scale. Although such decisions are now a result of a Full Statutory Assessment in which parents’ wishes are significant, substantial numbers of educational psychologists across the UK still use psychometric tools. Despite being modernised to include tests such as the WISC-R and the BAS (British Ability Scales) their core constructs remain unaltered.

This is surprising as the shortcomings of such tools have been long known and debated among educational psychologists. Yet scores are still demanded particularly around those for whom measurement is the most difficult. There is a wealth of literature critical of the role and negative impact of IQ testing (Leyden, 1978, Lokke et. al, 1997; Leadbetter, 2005, Farrell and Venables, 2008) and yet educational psychologists still spend much of their time undertaking formal special education evaluations using psychometric assessment including IQ tests (Shapiro et al., 2004 and Farrell and Venables, 2009).

Test scores are appealing, offering the immediate and seductive appeal of a spuriously precise, defined result in a complex educational world.

Why are such tests so problematic?

The tests were primarily designed for white, middle-class children and are unfair and invalid when used on children from different backgrounds. Attempts to create culturally neutral tests have proved unsuccessful; no test has been found that does not reward some cultural groups over others. Intelligence may be as great in different groups, but questions may need to be approached differently due to differences in cultural background. The tests have been challenged in court for racial and cultural bias, but there have been no definitive rulings on them.

So much caution has to be applied when administering and interpreting such assessment processes with different cultural groups that major validity questions are raised on every occasion. It has been shown that test outcomes can depend on familiarity with the test materials, the procedure and the examiner.

“No one would believe until I demonstrated it with controls that the IQ scores of pupils from an open air school could be lifted 10 points or so by thawing them out on the hot water pipes for half an hour before testing.” (Head of Special School-quoted in Galloway and Goodwin, 1979)

In one US experiment, asking 99 school psychologists to independently score an IQ test from identical records resulted in IQs ranging from 63 (mild learning difficulties) to 117 (gifted) for the same individual. In addition, differences in the interpretation of test scores for entire groups have been documented (Ropers and Menzel, 2007).Anxiety is also known to affect test scores. If being tested makes you anxious you will score lower.

IQ tests only capture a few aspects of many different ‘intelligences’ or ‘systems of abilities’ omitting, for example, creative and practical intelligence, social, emotional and moral intelligence, and lateral and radiant thinking. Wisdom is not considered. IQ tests are ‘static’ (‘What has the child learned?’) rather than ‘dynamic’ (‘What does the child achieve when given guided feedback?) – they measure not intelligence but a child’s attainments in arbitrarily selected skills. They only measure a sample of situations in which so-called intelligent behaviour is revealed and do not capture the complexity of real-life situations. Intelligence tests have been criticized for their limited ability to predict non-test or nonacademic intellectual abilities.

Critics assert that potential is gauged by simply adding up correct answers, ignoring how a child has arrived at them; but research has demonstrated that the child who answers wrongly may understand as much about a problem as the one who answers correctly, perhaps by guessing.

A central criticism of IQ tests is that they are used to distribute limited resources and provide rewards: special classes for gifted students, admission to college, employment or the opposite with special education placement. Those who do not qualify for resources based on test scores may feel thwarted and resentful. Negative assumptions have been initiated, aspirations lowered and self-fulfilling prophecies created. Unfortunately, intelligence test scores have become associated with self-worth.

At worst such assessments have been used to wrongly place pupils from ethnic minorities in special schools and units. The PLASC and School Level Annual School Census (2002) revealed Black Caribbean pupils were over represented in Pupil Referral Units (5.8% compared with 1.5% in mainstream schools). Even more relevant was that 3.6% of Pakistani pupils were in special schools. Would this have anything to do with factors such as poverty? Or are some pupils still being assessed and doing badly on culturally biased tests?

Dyson and Gallannaugh (2008) have also considered the disproportionate presence of students from different social groups in the UK special needs system and argue that it reflects broad educational and social inequalities.

Many intelligence tests produce a single score. This is inadequate in explaining the multidimensional aspects of intelligences. Two people can have identical scores, yet one may have obtained the score due to strong verbal skills while the other may have obtained it due to strong skills in perceiving and organising various tasks.

Linda S. Siegel (1992) proposes we abandon the IQ test in the analysis of the disabled child. According to most definitions intelligence consists of logical reasoning, problem solving, critical thinking, and adaptation. However, examining the content of IQ tests, they test virtually none of these skills.

Siegel gives a detailed analysis of the subtests of the Wechsler Intelligence Scale for Children-Revised (WISC-R), often used in diagnosing learning difficulties. In each subtest of the Verbal scale, performance is in varying degrees dependent on specific knowledge, vocabulary, expressive language and memory skills, while in the Performance scale, visual-spatial abilities, fine motor coordination, perceptual skills, and in some subtests speed, are essential for scoring.

According to Siegel it is a paradox that IQ scores are required of disabled people, many of whom have difficulty in one or more of these skills. They may end up with a lower IQ score than a non-disabled person, even if they have identical reasoning and problem-solving skills.

Most tests are carried out against the clock. If you are slow because of movement differences or learning style you will do worse. If doing things is hard for you because of any kind of physical impairment or difference then you will score less well against a ‘typical ‘population.

Another assumption is that an IQ score should predict reading ability. However, many individuals have low IQ scores and are very good readers, making a nonsense of this way of thinking.
IQ scores and psychometric test results are clinically focused on the child or young person’s deficits especially if they have additional support needs. They provide one answer to the vexing question ‘What is wrong with you?’

“I scored relatively high in an IQ test when I was a child. Since then I have done many many many very very very stupid things in my life. I still wonder what that test has to do with intelligence or understanding at all.” (Alex Wien, Austria, 2009)

Many people assume intelligence tests measure inborn intelligence that will never change, when in reality they are based on an individual’s interaction with the environment and can never exclusively measure inborn intelligence – if such an entity even exists. People continue to learn throughout their lives and no-one has proved the existence of fixed potential, a ceiling that lasts a lifetime.

Anne Donnellan (1994), recommended adoption of the “Least Dangerous Assumption.” When faced with a disabled child who does not appear to be learning, educators can either assume that she is incapable of learning and segregate her from her peers, or keep on exposing her to learning. Whether the child in fact learns nothing, or simply cannot communicate what she learns, the latter is by far the least dangerous assumption.

Intelligence testing is still widely relied on in allocating scarce resources in the special educational needs system in the UK and SEN tribunals are over-fixated on the percentiles scored in the WISC Test. An inclusive approach which respects disability equality is based not on labelling and attachment of scores but on the needs of the child in a mainstream inclusive environment, identifying supports and reasonable adjustments to help them be involved and progress in their learning at a challenging pace that suits them.

With the Government drawing up legislation for selective education this will again be based on IQ type testing to select the most able. In the 50s and 60s educationalists learned to their cost that selection by ability was grossly unfair as children developed in different ways and at different rates. By the age of 18 often those who had failed the 11+ exam outperformed those who had passed, and the test results had little relation to life success. Let us not make the same mistakes again.

Colin Newton, with concluding paragraphs by Richard Rieser


  • Donnellan, A. M. & Leary, M. R. (1995). Movement differences and diversity in autism/mental retardation: Appreciating and accommodating people with communication challenges. Madison, Wisconsin: DRI Press.
  • Gallannaugh, Frances and Dyson, Alan The Journal of Special Education, Vol. 42, No. 1, 36-46 (2008) DOI: 10.1177/0022466907313607 Disproportionality in Special Needs Education in England: University of Manchester
  • Gardner, Howard. Frames of Mind: The Theory of Multiple Intelligences. New York: Basic,1983
  • Intelligence Quotient: Prof. Dr. Hans-Hilger Ropers/ Prof. Dr. Randolf Menzel (2007)
  • J Leadbetter. 2005. Activity theory as a Conceptual Framework and Analytical Tool within the Practice of Educational Psychology, Educational and Child Psychology, 22, 1, 18‐28. ISSN: 0267‐1611.PLASC and School Level Annual School Census 2002
  • Leyden, G. (1978) Reconstructing Educational Psychology by W E C Gillham: Croom Helm
  • Lokke, C., Gersch, I. M’gadzah, H. and Frederickson, N. (1997) The resurrection of psychometrics: fact or fiction? Educational Psychology in Practice, 12, 4, 222-233
  • IQ Test: Where Does It Come From and What Does It Measure? Jan Strydom, M.A., H.E.D., D.Ed. & Du Plessis, B.D., B.A. Hons (2000)
  • O’Brien, John (2002) Inclusion News. Article: ‘Great Questions and The Art of Portraiture’. This essay was part-inspired by the work of Sarah Lawrence-Lightfoot, a sociologist at the Harvard School of Education.
  • Rossetti, Z. & Tashie, C., (2006) The Least Dangerous Assumption, University of New Hampshire, Institute on Disability
    Shapiro, ES Angello, LM, Eckert TL, School Psychology Review, 2004 – Has Curriculum-Based Assessment Become a Staple of School Psychology Practice? an Update and Extension of Knowledge, Use and Attitudes from 1990 to 2000.
  • Siegel, L. S., & Metsala, E., “An alternative to the food processor approach to subtypes of learning disabilities,” in N. N. Singh & I. L. Beale (eds.), Learning Disabilities: Nature, Theory, and Treatment (New York: Springler-Verlag, 1992), 45
  • Smith, C. R., Learning Disabilities: The Interaction of Learner, Task, and Setting (Boston: Allyn and Bacon, 1991), 63
  • Gary Thomas and Andrew Loxley Special Education and Constructing Inclusion (2007) by Open University
  • Venables, K. and Farrell P. in A Psychology for inclusive education : new directions in theory and practice / edited by Peter Hick, Ruth Kershner and Peter Farrell (2009)
  • Alex, Wien, Austria (2009)
  • Wiggins, G. P., & McTighe, J. (2006). Examining the teaching life. Educational Leadership, 63, 26-29.
  • Wilson, D. 2009: FOR A STORY vs. LISTENING TO A TORY’ (Unpublished Paper)