What Do Dyslexia Assessment Scores Actually Mean?

When parents receive a dyslexia assessment report, one of the first things they notice is the numbers. There are scores for reading, spelling, memory, processing speed, and more, and it isn't always obvious what any of them mean. This post explains the scoring system used in professional assessments and what different results actually tell you about your child.

What is a standardised score?

A standardised score is a way of comparing your child's performance to other children of the same age. Rather than just saying how many questions they got right, it places their result on a scale that accounts for what is typical for their age group. Most standardised tests used in dyslexia assessments use a scale where the average score is 100.

Reading the bell curve

You may have seen a bell curve diagram in your child's report or heard the term used by an assessor. It describes how scores are distributed across the population, and it's one of the most useful tools for understanding what a result really means.

The diagram above shows how scores fall across that scale. Most children score somewhere in the middle, between 85 and 115, which covers the average range. Scores below 85 start to indicate increasing difficulty relative to peers, and scores above 115 indicate relative strength.

Dyslexia score chart: understanding standard scores

The chart below sets out how standard scores are typically described in a professional assessment report. Most standardised tests used in dyslexia assessments have an average score of 100.

• •131 or above — well above average: a significant strength in that area.
• •116 to 130 — above average.
• •111 to 115 — high average.
• •90 to 110 — mid-average, where most of the population falls.
• •85 to 89 — low average.
• •70 to 84 — below average: typically signals a meaningful area of difficulty.
• •69 or below — well below average: a significant difference from what would be expected for a child of that age.

A chart like this is a guide, not a verdict. Each individual test must be interpreted within the wider assessment profile, alongside background information and the assessor's observations. One score alone does not diagnose dyslexia, and a below-average score in a single area can mean something quite different depending on the pattern across the rest of the assessment.

A chart like this is a guide, not a verdict. Each individual test must be interpreted within the wider assessment profile, alongside background information and the assessor's observations.

Why do assessments test so many different things?

Dyslexia affects a cluster of skills rather than just one. A thorough assessment will typically look at reading accuracy, reading fluency, spelling, phonological awareness, phonological memory, and processing speed. Some assessments also include measures of working memory and expressive writing. Each area generates its own score, and the pattern across all of them is what helps an assessor build a full picture.

This is important because a child might perform within the average range on a single reading task whilst showing significant difficulty in phonological processing or memory, and it is often that underlying pattern that points most clearly to dyslexia.

What a low score doesn't mean

A below-average score in one area does not define your child's intelligence or their potential. Standardised assessments measure specific, narrow skills at a point in time. Many highly capable individuals show significant difficulty in areas like phonological processing or processing speed whilst demonstrating real strengths elsewhere, in reasoning, creativity, verbal expression, or problem-solving. A good assessment report will highlight both.

What happens next?

Understanding the scores is a starting point, not an end point. The assessor's conclusions and recommendations section of the report translates those numbers into practical guidance, for school, for home, and in some cases for access arrangements in exams. If anything in the report feels unclear, you are always entitled to ask for an explanation.

Additionally, if your child's school has received a copy of the report and you are unsure how they are acting on it, a meeting with the SENCO is a reasonable and worthwhile next step.

At Defining Dyslexia, we always make time to talk parents through findings at the end of an assessment. A number on a page is only useful if you know what to do with it.