How is Dyslexia Measured?

There is no standard measurement for dyslexia. Different countries’ official associations, as well as their national governments, have no common agreement on a reliable way of measuring how many dyslexics there are, and without such a measurement, the prevalence of dyslexia appears to change from country to country (and even region to region within a country). The Dyslexia Compass takes an international perspective, examining and comparing what various bodies understand dyslexia to be, and how they test for it, in order to arrive at a common understanding that is satisfactory to all and can provide a means of aligning rates of dyslexia across borders.

Spain
Tests are factored against a subject’s clinical history, their reading, writing, and speaking skills, their maths skills, their time management, their personal organisation, and cognitive skills such as: memory, attention and concentration, perception, their spatial orientation, their psychomotor coordination, and their sequencing abilities. Questionnaires are used, as well as oral questioning, measuring the pupil’s ability to follow instructions and to copy, and official testing on “three phonological components independent of reading”.
Austria

Comprehension and reading accuracy tests are performed, and intelligence testing is used.

In Austria it’s common to use a “discrepancy model”, looking for mismatches between intellectual ability and school success.

Romania

Romania takes a discursive approach, arranging meetings with parents and therapists, teachers, and pupils. Psychological testing is emphasised, and unspecified linguistic exercises are used in the identification process. Skills disorders must last for at least six months to be considered as dyslexia, even when specialist intervention is being provided in the meantime.

Norway
Norwegian specialists use interviews with teachers, pupils and parents. A range of phonological, literacy, and memory assessments are used, and these focus not only on weaknesses but potential strengths among children being tested.
Sweden
National standardised tests are employed, along with pedagogy examinations and examinations by a school health team, interviews with parents, pupils and teachers, and a comparison of reading and writing abilities with other academic abilities.
The UK
A mixture of psychometric and intelligence testing is used, gauging different forms of intelligence. There are also motor control tests, memory tests, reading and writing tests, and sequencing tests (finding, sorting, matching, etc). Often but not always, measurements need to be taken that highlight the differences between “dyslexic deficits” and other non-deficit cognitive skills (a discrepancy model).
Croatia
Dictation is used to test dyslexic traits, as are focused writing tasks.
France
Only the difficulties manifest in a dyslexic child are investigated in France. Testing is carried out by medical practitioners.
Germany

In a large sample of German children, the prevalence of dyslexia was between 1.9% and 2.6% when the criteria used included a reading score of 1.5 to 1 standard deviation below the norm and average performance in at least one other cognitive measure. However, the rate jumps to a range of between 7.1% and 15.6% if only the reading score of 1.5 to 1 standard deviations below the norm is used, with no “discrepancy model”.

There are no national guidelines on how to test, what standard deviations to use, and whether to use discrepancy models, in Germany.

Denmark
Reading tests, word recognition (involving pictures), spelling and non-word spelling tests are used, as well as a range of phonological tests. There is a colour-coded system of “dyslexia severity”, ranging from “green” (mild dyslexia) through “yellow” (moderate dyslexia) to “red” (severe dyslexia).

This international perspective is crucial. Dyslexia provision across national borders is inconsistent and hence patchy, and until there is some consensus about what dyslexia is, this will always be the case. And while it’s the case, there will be children who are not being adequately provided for. The moral spine of the Dyslexia Compass is to keep these under-provided children in mind, and – perhaps – provide the grounding for better help. Dyslexia needs to be understood consistently, and rates of dyslexia need to be measured similarly internationally if the most vulnerable among us are to be properly served.

The key to aligning different national measurements is in first creating an internationally acceptable understanding of what dyslexia is. It’s important to realise that where organisations concentrate on different indicators for dyslexia, they are unlikely to discover dyslexia in the same way as other organisations – if they discover the same thing at all. It is therefore important to ask the question: what are the indicators that are being looked for in different countries?

Country
What are they looking for?Methodologies
Austria
The focus is on behavioural disorders, word comprehension, sentence comprehension, text comprehension, phonological decoding, blending and synthesis, reading speed, spelling and language skills, logical thinking, processing speed, and memory skills. Spelling is looked at, and reading speed is checked.Comprehension and reading accuracy tests are performed, and intelligence testing is used.

In Austria it’s common to use a “discrepancy model”, looking for mismatches between intellectual ability and school success.
Croatia
Phonological memory, phonological awareness, processing, and decoding, are looked at, as are reading and writing fluency, text comprehension, working memory, letter naming, repetition of sentences and pseudowords, visual perception, and rapid naming abilities.Dictation is used to test dyslexic traits, as are focused writing tasks.
Denmark
[Not enough information available]Reading tests, word recognition (involving pictures), spelling and non-word spelling tests are used, as well as a range of phonological tests. There is a colour-coded system of “dyslexia severity”, ranging from “green” (mild dyslexia) through “yellow” (moderate dyslexia) to “red” (severe dyslexia).
France
[Not enough information available]Only the difficulties manifest in a dyslexic child are investigated in France. Testing is carried out by medical practitioners.
Germany
[Not enough information available]In a large sample of German children, the prevalence of dyslexia was between 1.9% and 2.6% when the criteria used included a reading score of 1.5 to 1 standard deviation below the norm and average performance in at least one other cognitive measure. However, the rate jumps to a range of between 7.1% and 15.6% if only the reading score of 1.5 to 1 standard deviations below the norm is used, with no “discrepancy model”.

There are no national guidelines on how to test, what standard deviations to use, and whether to use discrepancy models, in Germany.
Norway
Assessors here check for phonological ability (decoding, blending, identification, manipulation, awareness…), reading and writing fluency and comprehension, letter recognition, pseudoword recognition, recognising orthographic patterns, short-term and verbal memory skills, and background issues such as the home environment, mental health issues, and overall language skills.Norwegian specialists use interviews with teachers, pupils and parents. A range of phonological, literacy, and memory assessments are used, and these focus not only on weaknesses but potential strengths among children being tested.
Romania
Those testing for dyslexia generally look for reading speed and comprehension, but also reading accuracy. Other things tested include pronunciation disorders (dyslalia), oral skills, delays in language development, vocabulary acquisition, and phoneme recognition.Romania takes a discursive approach, arranging meetings with parents and therapists, teachers, and pupils. Psychological testing is emphasised, and unspecified linguistic exercises are used in the identification process. Skills disorders must last for at least six months to be considered as dyslexia, even when specialist intervention is being provided in the meantime.
Spain
Assessors first look for letter recognition, then the ability to distinguish pseudowords, then grammatical recognition and competence, then syntactical competence, and finally comprehension.

They look for reading abilities and visual scanning, writing and spelling tests, exercises testing motor consistency, copying, rapid naming, sequencing abilities, maths, rhythm, and personal history. Research indicates that they also test for hearing, though they don’t appear to name auditory processing or hearing issues as among the signs of dyslexia they are looking for.
Tests are factored against a subject’s clinical history, their reading, writing, and speaking skills, their maths skills, their time management, their personal organisation, and cognitive skills such as: memory, attention and concentration, perception, their spatial orientation, their psychomotor coordination, and their sequencing abilities.

Questionnaires are used, as well as oral questioning, measuring the pupil’s ability to follow instructions and to copy, and official testing on “three phonological components independent of reading”.
Sweden
Assessors here check for phonological abilities (decoding, blending, identification, manipulation, awareness…), along with reading, writing, and spelling fluency, listening comprehension skills, the ability to read rapidly-presented words, the ability to read and distinguish pseudowords and non-words, recognising orthographic patterns, working memory skills, and background factors such as the home environment, general confidence levels, and mental health issues. Also, the ability to distinguish between homophones is checked, as well as logic and perception skills, auditive, visual and attention skills, and spatial awareness.National standardised tests are employed, along with pedagogy examinations and examinations by a school health team, interviews with parents, pupils and teachers, and a comparison of reading and writing abilities with other academic abilities.
The UK
A range of abilities is looked at, including, though are not exclusive to: phonological awareness, phonological memory, working memory, reading speed and reading fluency, finding words in letter chains, spelling abilities, vocabulary range and receptive vocabulary, writing, handwriting, and letter formation, motor control, sense of number and mathematical ability, logic and reasoning, cognitive processing speed, and rapid naming ability / deficit.A mixture of psychometric and intelligence testing is used, gauging different forms of intelligence. There are also motor control tests, memory tests, reading and writing tests, and sequencing tests (finding, sorting, matching, etc). Often but not always, measurements need to be taken that highlight the differences between “dyslexic deficits” and other non-deficit cognitive skills (a discrepancy model).

In terms of methodological considerations, three main points stand out as of interest: whether a discrepancy model should be used; whether confidence intervals should be used; and what sort of standard deviation from the reading norm should be used.


All these issues are key to the provision of an alignment between different national measurements, an alignment which will contribute towards better accommodations for the under-served dyslexic children of Europe. The Dyslexia Compass works by helping to bring understanding and measurements together, bringing together different national definitions and measurements of dyslexia, and helping provide the grounding for consistent, and internationally agreeable, accommodations.

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