What are Full Diagnostic Assessments for Dyslexia?

Updated: Jul 1

A full diagnostic report is a document which is written after your child has completed a series of psychometric tests with either a specialist teacher or an educational psychologist.

The assessor, who is either a specialist teacher who holds an assessing practicing certificate or an educational psychologist, will decide which tests are appropriate for your child.

If you would like to know whether a diagnostic assessment is appropriate for you, please arrange a free 15 minute call with me here.

Background information covering your child’s relevant medical, educational and social background will be gathered from yourselves and information about their literacy abilities will be sought from their school.

This information will form the basis upon which the relevant tests are decided. For example, if everyone states that concentration is an issue then tests which measure this can be included. The background information also gives as much information to the assessor as possible.

There are a lot of psychometric tests which can be used, but for the main part the key areas which are explored during a full diagnostic assessment are as follows:

- Underlying ability:

This may seem a strange one to do but the tests here usually confirm that there is no reason why your child shouldn’t be able to learn at school, which is important to show.


All children with a specific learning difficulty will have an issue with memory. These tests explore which areas of memory are affected. In Dyslexia, verbal memory is the key one which is affected, often with a good visual memory.

However, many of the children I assess have a weakness in areas of their memory relating not only to language but also the visual areas. This can make learning more difficult for them and it is important to know this as they will need more repetition and really good strategies put in place to allow them to place their learning in long term memory.

- Processing speed:

This is an important area as some children take longer to understand what they are being taught or how to do the task that they have been set. This can be explored in terms of rapid naming speed and writing speed.

The above two areas of memory and processing speed can trigger the exam accommodation of extra time if your child’s score falls into a below average category.

- Phonological awareness:

This is a posh way name for exploring whether your child can discriminate and manipulate sounds in words. This is a key skill which needs to be developed to enable your child to become a good reader and speller.

It is possible to become a good reader at primary school without developing this skill ( your child will have a very good visual memory), but they will struggle to read more complex vocabulary at secondary school and will remain a poor speller if they haven’t fully developed their phonological awareness.

This part also encompasses whether they can retrieve phonological information and manipulate it through their working memory – something which is important for spelling.

- Attainment tests:

These look at where your child currently is with their literacy skills.

These can cover a range of areas such as vocabulary development, explore the difference between listening comprehension and comprehension when they have to decode the words themselves ( this comparison can be interesting as it shows what they are capable of doing if we take away decoding words from them), writing development and spelling skills.

The idea with these is that you are comparing attainment with the results from the other tests and also with the background information to look for evidence for why there are difficulties for that child.

The tests will also show up areas of strength. This can really help with planning how your child can progress with their studies – I’m a firm believer in exploiting strengths!

Once all the evidence has been collated from questionnaires and the testing, then it is down to the assessor’s judgement whether the difficulties evidenced conform to a definition of a specific learning difficulty such as dyslexia.

The key reason that this is important is because learning difficulties which have been diagnosed, such as dyslexia, have legal protection under the Disability Act 2010, meaning that schools and employees cannot discriminate against a dyslexic student and they have to make reasonable adjustments to prevent this.

In state schools they are also covered under Special Educational Needs Legislation.

If there is no official diagnosis in place, then your child will not benefit from this protection.

Misconceptions about Formal Testing

There are a lot of misconceptions about assessments, the key one that I hear is that you don’t want to label your child. I would agree that labels can be unhelpful. Two dyslexic students may have different strengths and weaknesses and if we just think of them as ‘dyslexic’ i.e. as one homogenous group, then we still may not be able to teach them effectively.

The key factor about assessing is exploring why your child is struggling with aspects of their learning. As an assessor, my overriding objective is to obtain a clear picture of your child’s learning strengths and weaknesses.

Are they struggling because they don’t have a wide vocabulary? Is it because they haven’t developed the initial skills required for reading and spelling? Are there weaknesses in their ability to store their learning in long term memory? Are they able to hold and manipulate information in their head (called working memory) or is this an issue?

There is another key reason why a diagnostic assessment is important for your child’s success. As stated earlier, one of the objectives is to understand what is ‘blocking’ your child in developing their literacy and/or numeracy skills. The psychometric tests do provide the answers for this and enables the assessor to put together an individualised programme of effective support and classroom strategies which will enable your child to progress in these areas.

This part of the diagnostic assessment means that you, as a parent, will understand the needs of your child better. You are then able to hold meaningful discussions with your child’s Special Educational Needs Coordinator (SENCo) as to how they can support your child. This will enable you to understand whether their suggestions will enable your child to move on or whether it is inappropriate for them and a waste of time.

Many SENCos are very experienced teachers and have lots of knowledge around learning issues, but without assessing a child using psychometric tests they will not have the actual detailed knowledge of your child’s specific strengths and weaknesses.

In my experience, a dyslexic child will be given more phonics teaching without knowing whether they can discriminate the sounds in words. This means that the phonics teaching will be unsuccessful at that point.

Many schools assume a dyslexic child will be great at learning visually (i.e. through their eyes), again without exploration you don’t actually know, and it isn’t always true.

These are areas a diagnostic assessment will explore and advise on. In reality, without these tests you are really just throwing learning at a child and hoping some of it might stick without really understanding why it is or isn’t working for them.

I have engaged with many parents about whether obtaining a formal diagnostic assessment had made any difference to them and these are some of the quotes I had back:

“Eventually opted for an assessment with a specialist teacher, which was pretty straightforward and so glad that we did this - actually knowing for sure was a relief for ourselves as parents and also our son. The report was really informative and provided many recommendations specifically tailored to him.”

“As a family we felt a huge sense of relief with an official diagnosis from a specialist teacher for our son, but at the same time this has been tinged with sadness at the thought of his everyday battle for the last 6 years and the struggles that he will face in his future. But, the diagnosis means we are better equipped to support him and fight for the help he will need.”

“I have no regrets about the assessment , it was the best thing we ever did and she really benefited from knowing. The first thing she said when I told her was “ahhh. So I’m not stupid”

“Best thing we did. After being told by the SENCO ‘She can’t be dyslexic she doesn’t write her b's and d's round the wrong way,’ it was a validation of what we suspected, ‘moderate dyslexia’. There’s no way any help was coming before we had a formal diagnosis.”

If you would like to discuss whether a full diagnostic assessment is appropriate for you or your child, please contact me here to arrange a free 15 minute chat


If you would like to join a friendly and supportive online group of parents and specialist teachers to learn more about dyslexia then you can do so here.

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