Dyslexia Assessment Tests


This page covers

        How your test results are presented
        Intellectual ability
        Cognitive skills



When you've read this, you may like to get your own assessment report out and look at it again. The Assessment Report Activity helps you to understand your report by making some notes from it.


How your test results are presented

The majority of tests used in the assessment of dyslexia are 'standardised'. This means that they have been used on a large group of people selected to be representative of a particular group of the population.  Age is one of those criteria.  So if we say that a particular test has been standardised up to 18 years, that means that the results are only true for people up to the age of 18. That doesn't mean to say that such results cannot be useful. The best tests for adults, however, are those that have been standardised for the whole adult range.


A standardised test gives a direct comparison between you and that population for that particular test. You can also compare your performance in one test with that of another – compare your reading to your spelling ability for example.


The standardised results of such tests can be described in several ways:



Standard score




This figure is calculated from your actual score.


68% of the population fall within the range 85 - 115

Percentiles are expressed as figures from 1 – 99. If you are in the 65 percentile this means that you have reached a level higher than 65% of people for that test.

Words can describe the range that your standard score falls into:


High average

Above average etc.



~75 percentile


High average



~25 percentile


Low average



~95 percentile

Above average


Remember, the important thing about using standardised scores, rather than actual test scores, is that we can make comparisons between tests. This is important because tests vary as they test for different things.


Simply put, a diagnosis of dyslexia is made on comparing your intellectual ability, your cognitive ability and your attainment level.  A significant difference between intellectual and cognitive abilities is crucial in the diagnosis of dyslexia. This may become a little clearer if you read on.


Intellectual ability

Your 'underlying' or 'general' intellectual ability is a good guide to what you can achieve depending on how motivated and supported you are.  You may hear this described as 'IQ' or 'intelligence'. Whatever, it will involve non-verbal and verbal reasoning tests of some kind.


It should not be a case of measuring IQ as a precise figure, rather, it should be a case of establishing which ability range you are in*. In your assessment report you will find details of which tests were used. It may have been one of the following:

       WAIS (I, II or III) Wechsler Adult Intelligence Scale

       WISC - Wechsler Intelligence Scale for Children

       BAS - British Ability Scales

       Ravens Progressive Matrices

       K-BIT – Kaufman Brief Intelligence Test

       WRIT – Wide Range Intelligence Test


If your report quotes a figure for your intellectual ability, there is no need to take this as absolute. It is a very imperfect measure.  Results, for example, will be affected by:

         how you perform on the day

         how nervous you are

         how many times you have done psychometric tests before

         your cultural background

         your education background

         the fact that dyslexics are known to under-perform on these tests, particularly the verbal subtests

*Your best approach is to translate any figure quoted into the broad terms, for example:


Standard score table


Here are a couple of examples

Intellectual ability = 101

Hari was told his 'general intellectual ability' was 101.

Hari is of average ability

Look for 101 on the top line. On the band below you can see that he is right in the middle of the average ability range, just above the mean of 100.

– the same as 68% of the population

68% of the population falls into this ability range so you might like to divide it up a bit more: top, middle or lower average.


Hari's IQ is middle average. Reading off the bottom line - this means that his intellectual ability is in the range where 25-75% of the population fall - just a bit better than 50%(half) of the population. Since the aim is for 50% of people to go to university, he can expect to cope with study at that level - but, as he is at the lower end of that group, he is likely to find it quite hard work so his choice of course will be very important.


Jo's IQ was measured at 128. From the chart you can see that 128 corresponds to the 'above average' ability range. Only 14% of the population fall into this range. She is very able, more able than over 91% of the population (the percentile).


Don't forget that other things count when it comes to success, such as motivation, interest and confidence.


So you can see that measuring intellectual (or cognitive) ability only gives a guide to what you might be capable of.


Cognitive skills

The next step is to measure your cognitive skills, in other words, how well your brain deals with information while doing particular key tasks. In identifying dyslexia the following are measured:

·        Working memory (auditory and/or visual)

·        Phonological skills

·        Fluency – the rate that the brain processes information

·        Visual disturbance – probably related to the rate the brain processes visual information

·        Automaticity – how your brain copes with automatic tasks


The results of these tests can then be compared with your intellectual ability scores. In dyslexia some, or all, of these cognitive skills are generally much lower - at least one ability band lower than intellectual ability, sometimes two.



Attainment tests look at your ability in reading and writing tasks, copying, spelling and maths. With adults, it isn't just the test results that are important but the way you have tackled things - the strategies you are using, and the types of errors you are making.

Many adults have highly sophisticated coping strategies that hide their real difficulties. It is important that these are identified as it will give you something to work on - using your strengths to help with your difficulties.

Many adult dyslexics do well, but usually with huge effort. Such adults are often described as compensated dyslexics. If you fall into this category, it doesn't mean that you have been cured! Nor does it mean that you are coping without difficulty – don't be fobbed off. You might do even better with more help!



Good assessment reports will include recommendations for you to consider. These will include



Our comments

Work to be done

(often referred to as remedial work)

Needs to be considered carefully. Many adults will not want to do structured, repetitive work, and it is questionable whether the dividends are worth it. It depends on what you want to achieve and your strengths.


Building on your strengths

Very useful. Keep a record of how you do things successfully.

Ideas for strategies

Very useful. Try them out and don't be afraid to adapt them to suit you.

Technology – high, medium and low tech.

Developing all the time. Don't go out and buy it all. Read Chapter 11 first. Seek advice from a specialist – see appendix c.

Personal support

Some of the recommendations could be adapted and used by your close friends and family, and your employer.

If you are a student this may be one-on-one support with a specialist tutor. 



Book Information / Buy the book