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What is Dyslexia?

In English-speaking countries, the dyslexia label is professionally applied to some individuals who have severe difficulty with word decoding and spelling accuracy. Unfortunately, the medical-sounding label implies that it is a distinct and identifiable disorder with a known medical cause. As Prof. Dorothy Bishop points out, ”(M)edical-sounding terms are more successful memes than the descriptive terms because they convey a spurious sense of explanation, with foreign and medical-sounding labels lending some gravity to the situation…they are treated seriously and gain public recognition and research funding.”

In European countries with transparent spelling codes, where nearly every child is able to decode single words accurately after just a few weeks of phonics instruction, the dyslexia label is applied to some individuals who are considered to be very slow readers. See Myths 14 and 15 Dyslexia Myths and Facts

For a considerable length of time, one particular definition of dyslexia (IQ-achievement discrepancy where reading age is considerably lower than IQ would predict), was used as the basis for all diagnoses and research on the subject. It was eventually discredited: ”(T)here is little evidence that the long-term development of poor readers who are IQ–achievement discrepant is substantially different to that of poor readers who are not IQ–achievement discrepant, nor does IQ–achievement discrepancy reliably distinguish between those who are difficult to remediate and those who are more easily remediated. Consequently, IQ–achievement discrepancy is no longer the bedrock for identification of LD in the US (or of dyslexia in the UK, for that matter).” (Singleton 2009 p17)

The demise of the IQ–achievement discrepancy definition created serious difficulties for those working in the specialist field of dyslexia. They needed another way to diagnose it; one that didn’t require an IQ test. In the UK, the British Psychological Society (BPS) produced a ”working definition” which they simplified to, ”marked and persistent problems at the word level of the NLS curricular framework” (BPS 2005 p20). This working definition enabled professionals involved with ‘dyslexia’ assessment to carry on diagnosing the difficulty and allocating the label, if they wished, purely on the basis of subjective opinion and guesswork.

The British Psychological Society’s definition of dyslexia (BPS 2005. p18) is a working definition, not an operational one (BPS 2005. p19). The BPS notes that ”For a word to be used as a scientific concept, it must satisfy certain criteria…currently dyslexia does not meet such stringent requirements” (BPS 2005. p17)

Response To Intervention (RTI) is sometimes used for diagnostic purposes. Unfortunately, RTI is as imprecise and as questionable as other forms of dyslexia diagnosis, and there’s the rub; without an internationally agreed operational definition of dyslexia – which is the first step in scientific research, meaning that there must be a precise (infallible) measure of what it is you’re going to study, scientifically valid diagnosis cannot take place. This means that all research that used/uses the IQ discrepancy model diagnosis, the ‘Bell Curve’ diagnosis (the bottom x% on the bell curve of reading ability) or RTI to select ‘dyslexic’ subjects, is null and void, as is research based on any of the other definitions -see Rice & Brooks 2004 appendix 1. p133 for a range of definitions.

”When reading literature claiming that ”dyslexics‟ exhibit this or that symptom, or behaviour, it obviously behoves us to ascertain how the sample of ”dyslexics‟ was arrived at – how were they diagnosed. If it was by the discrepancy model of diagnosis, as is almost always the case, the findings are thereby rendered invalid and should, properly, be ignored. They seldom are. Indeed, such findings regularly march cheerfully on, underpinning and ”validating‟ later work, in bibliography after bibliography. The ”borders of pseudoscience‟ indeed.” (Hugo Kerr. Dyslexia chapter 2008)

”When something is operationally defined, this means it has parameters which can be measured with sufficient mathematical rigour that these measures can be relied upon to define the concept.”
(D. McGuinness)

In Prof McGuinness’s response to Hulme (Times Higher Education Supplement. 24/3/06) she
describes the problem with reading research studies that use the ‘isolated-groups design’

”A key point, and one that undermines the whole dyslexia diagnosis industry, is that most leading reading scientists (and also geneticists, neuroscientists, and cognitive scientists) use the term ‘dyslexia’ as a synonym for severe difficulty with reading.” (Prof Elliott. ResearchED Magazine 2019).

– ”Dyslexia is just another name for poor reading … Where you put the cut off between dyslexia and normal reading has to be agreed within your education system, your school – it could be a national policy, a policy within a local authority – there isn’t any gold standard.”
(Prof Snowling quoted by Elliott in ResearchED Magazine 2019)

– “There is no agreed-upon prevalence figure; that’s why we should not be talking about dyslexia as if it were a well-defined diagnosis for a well-defined group. I use the word as a descriptor for word-level reading difficulties…”
(Dr Louisa Moats)

– ”Dyslexia means “poor reader” in Greek. That is all it means.”
(Prof Diane McGuinness)

Moreover, most literacy experts acknowledge that there is no scientifically accurate way to differentiate between those with a special reading disability ‘dyslexia’ and ‘common-or-garden’ poor decoders and spellers:

– ”The data do NOT show that dyslexics are different from poor readers. There is no indication that dyslexics represent a unique group.” 
(Prof Linda Siegel)

– ”The underlying difficulty appears to be the same, the way these children respond to treatment appears to be the same, there appears to be no justification whatsoever for going in and trying to carve out a special group of poor readers. This is what 15 years of research, all over the world has shown can’t be justified on a scientific or empirical basis.” 
(Prof Stanovich in Mills. TV Ch4 documentary: The Dyslexia Myth 2005)

– ”Most people assume that dyslexia is a clear-cut syndrome with a known medical cause, and that affected individuals can be clearly differentiated from other poor readers whose problems are due to poor teaching or low intelligence. In fact, that is not the case.” 
(Prof Bishop 2010)

– ”Because there is no way to differentiate students with learning disabilities, the label is meaningless.” 
(Prof George Cunningham)

– ”(T)he word “dyslexia” has taken on a variety of interpretations over the years, and it has provided a vehicle for people who want to make a quick buck from distraught parents.” 
(Prof Tymms)

– “It is a dimension, it is more or less of something. There is no dividing line where you have it or do not. There is nothing to diagnose.” 
(Prof Plomin. TES. 2019)

– ”(A)ttempts to distinguish between categories of ‘dyslexia’ and ‘poor reader’ or ‘reading disabled’ are scientifically unsupportable, arbitrary and thus potentially discriminatory.” 
(Prof Elliott & Dr Gibbs)

– “It is widely accepted that the diagnosis of dyslexia is scientifically questionable and can be misleading.” We’ve known this for a long time – in 1974, the eminent child psychologist Sir Michael Rutter found that
“… the features said to characterise ‘dyslexia’ do not cluster together as they should if there were a single ‘dyslexic’ syndrome.”
(Warwickshire LEA quoted by Prof Burkard in Schools Week 2018)

– ”In our present state of knowledge it does not seem helpful for teachers to think of some literacy learners as ‘dyslexics’ and others as ‘ordinary poor readers.” 
(Dr Rice & Prof Brooks 2004)

– ”They learned what they were taught, period. There are no dyslexic kids. I mean, that is just a myth.” 
(Prof Engelmann. Children Of The Code interview)

– “I’m sorry, I have no idea what dyslexia is.” 
(Prof Pamela Snow)

There is no need to manufacture a neurodevelopmental defect to explain why a significant percentage (30+%) of children in English-speaking countries have great difficulty learning to decode and spell accurately: 

The cross-cultural comparisons1reveal that the source of English-speaking children’s difficulties in learning to read and spell is the English spelling system and the way it is taught. These comparisons provide irrefutable evidence that a biological theory of “dyslexia”, a deficit presumed to be a property of the child is untenable, ruling out the popular “phonological-deficit theory” of dyslexia. For a biological theory to be accurate, dyslexia would have to occur at the same rate in all populations. Otherwise, some type of genetic abnormality would be specific to people who learn an English alphabet code and be absent in people who live in countries with a transparent alphabet, where poor readers are rare. A disorder entirely tied to a particular alphabetic writing system is patently absurd and has no scientific basis.” (D.McGuinness ERI p3. bold added)

Map of Europe (Dehaene 2009 p231: data derived from Seymour, Aro & Erskine’s 2003 study) showing % of errors in word decoding at the end of the first year of formal school by country. At that time, nearly all children throughout the UK were taught using a balanced word reading approach, not high-quality phonics.

”Reading is Not a Biological Property of the Human Brain: The English alphabet code is one of the most opaque writing systems in the world with multiple spellings for almost every sound, and multiple ways to decode the same symbol. The fact that nearly every child in Italy can read, write, and spell after the first term in school, but 30% or more of children in England (or any English-speaking country) can scarcely read or spell anything after 4 or 5 years of school, tells us a lot about our writing system and the way it is taught. It tells us nothing about the human brain – unless one wanted to argue that Italians have entirely different brains to English-speaking people.”
(D. McGuinness’ response to Usha Goswami’s TES article ‘The language barrier’

Rutter and Yule. 1975 paper ‘The Concept of Specific Reading Retardation’
”[Rutter and Yule] point out that if dyslexia was a true genetic ‘syndrome’, then the heritability should be identical in different geographic regions. Yet the poor readers scoring in the bottom range were four times greater in London than on the Isle of Wight, evidence for an environmental effect.”
(D. McGuinness. WCCR p135. Rutter&Yule 1975 p194).

”Aggregate children entering school all have the minimal prerequisites to be taught how to read…Since the kids all started with the same minimal prerequisites, the “deficiency” has to be in the instruction the children receive.”
(Prof Dick Schutz. Reading Dystestia: A Specific Measurement Disability)

”Dyslexia should be recognised as primarily an educational problem with an educational solution (at least until such time that research demonstrates otherwise)…”
(Profs Elliott & Grigorenko 2024)

Dyslexia: Still Not a Neurodevelopmental Disorder: https://www.mdpi.com/2076-3425/9/1/9
“We recently pointed out that there is no evidence to support the commonly held view that there is something wrong with the brains of children who have great difficulty learning to read.”

The first study to show clearly that ”the English spelling system and the way it is taught” (D. McGuinness ERI) is the cause of nearly all difficulties with word decoding accuracy and with spelling, was done by Heinz Wimmer in Austria (1993). German is spoken in Austria. It has a transparent spelling code and is taught using synthetic phonics. Wimmer tested all the worst readers in Salzburg sent to him by their teachers and found that they scored close to 100% correct on word decoding accuracy and nearly as well in spelling. Their only difficulty was in reading speed. Next, Wimmer collaborated with an English researcher Goswami (1994). They compared normal readers in Salzburg (7 yr. olds with 1 yr. of instruction) and London (9 yr. olds with 4-5 yrs. of instruction) reading comparable material. The Austrian children read the material as fluently and accurately as the English 9 yr. olds and made half as many errors. A third study by the researchers Landerl, Wimmer and Frith (1997) compared Austrian dyslexic children (slow readers) with English dyslexic children (slow and inaccurate readers). The Austrian dyslexics were not only far more accurate but also read twice as fast as the English dyslexics.

Early difficulties with single word decoding can lead extremely quickly to generalised cognitive, behavioural, and motivational problems: ”(S)kill at spelling-to-sound mapping (must) be in place early in the child’s development, because their absence can initiate a causal chain of escalating negative side effects … extremely large differences in reading practice begin to emerge as early as the middle of the first-grade year.” (Stanovich K. 2000 p162)

Dyslexia due to inadequate phonics teaching occurs in all social classes. As Prof Tom Burkard pointed out, ”There would not be such a huge industry charging obscene amounts of cash to (supposedly) remedy reading failure if it were not just as common with middle-class kids as with others.”
(Burkard. RRF messageboard 20/12/04)

Ruth Miskin, an early reading expert and past headteacher, warns parents, ”We’re not talking about poor kids here, from homes where televisions are always on. I’ve seen plenty of kids from affluent families,… pupils at private schools, the 4×4 parked in the drive. These children are often labelled dyslexic or SEN (with special educational needs). Not a bit of it: what they are is, to borrow an American acronym, ABT — ain’t being taught.”

”Socio-economic status is no protection from poor instruction.” 
(Dr. Louisa Moats quoted by Dianne Murphy)

”So it is mainly the middle-class children – whose parents believe government propaganda about improving schools, or who buy poor-quality private schooling in the sad belief that the writing of a cheque guarantees quality teaching – who get involved in the great ‘dyslexia’ fantasy. They know that something is wrong. The ‘dyslexia’ lobby persuades them that it is their children who are at fault. This helps relieve parents and schools of any responsibility for the problem. The children, too, are led to believe that they are in the grip of some force that is beyond their control. This is why so many people willingly co-operate in their own victimhood.” 
(Peter Hitchens. Mail on Sunday 04/06/07)

”30% of struggling readers come from households with at least one college-educated parent.” 
(EAB. Narrowing the 3rd-grade Reading Gap. p3)

Does Dyslexia exist? Stanovich. 1994.
p558. Whither Dyslexia? ”Thus, the research literature provides no support for the notion that we need
a scientific concept of dyslexia separate from other, more neutral, theoretical terms such as reading disabled, poor reader, less-skilled, etc. Yes, there is such a thing as dyslexia if by dyslexia we mean poor reading. But if this is what we mean, it appears that the term dyslexia no longer does the conceptual work that we thought it did.”

Does Dyslexia [as a distinct and diagnosable decoding disorder] Exist? Elliott & Gibbs. 2008.

Biologising reading problems: The specific case of dyslexia. João Lopes.

The Dreaded Dyslexia. It’s caused by a teaching disability, not a learning disability. Diane McGuinness

Specific reading disability (dyslexia): what have we learned in the past four decades?
Vellutino, Fletcher, Snowling & Scanlon. 2004.

Prof Pamela Snow: Dyslexia? We need to talk.

Prof Pamela Snow: Dyslexia Dystopia.

Dyslexia in the twenty-first century: a commentary on the IDA definition of dyslexia. Elliott & Grigorenko

Prof D. McGuinness: submission to the UK Parliament inquiry into reading interventions and dyslexia.

Prof Schutz. RTI: Response to Intervention or Really Terrible Instruction?