When a STen Score Isn’t the Whole Story

What a reassuring STen score didn't tell me about my daughter

(A Young Girl Reading by Jean-Honoré Fragonard)

This substack has taken me a little longer to write than usual because, unlike most of what I write, this one is personal.

Two weeks ago, my sixteen-year-old daughter was diagnosed with dyslexia.

Since then, I’ve spent quite a bit of time reflecting on that diagnosis and what it has meant, both as a mum and as someone whose professional life has centred on literacy and the early identification of reading difficulties. Like any parent, I found myself looking back over the years, wondering whether there had been signs that I simply hadn’t recognised when she was younger. I had spent a significant amount of time developing her phonemic awareness as a young child and she appeared to acquire this skill and letter-sound knowledge well.

However, as she got older and the literacy demands, particularly of secondary school, increased, the impact became more noticeable across a range of subjects. Subjects such as History, that depended heavily on reading, became more demanding, even when her understanding of the underlying content was good.

Yet, throughout primary school, her standardised reading test results were consistently reassuring. Year after year, she achieved STen scores of 8 and 9, placing her well above the average range for children of the same age. Neither her primary school nor her secondary school ever raised the possibility of dyslexia, although looking back, her English teacher did remark on her inconsistent spelling.

Much of my professional life has centred on literacy education, particularly dyslexia and the early identification of reading difficulties. I have spent years researching the topic, writing about it and speaking to teachers about the importance of identifying children before difficulties become established. I certainly did not expect my own daughter to receive a diagnosis at sixteen. The more I reflect on it, however, the more I realise that this is not simply a personal story. Her diagnosis prompted me to think again about some broader questions: how do we identify children who need additional support with reading and spelling in Ireland, and are we sometimes asking standardised tests to answer questions they were never designed to answer?

Before going any further, I want to be clear that this is not an argument against standardised reading tests. They have an important place within every school’s assessment system. They provide valuable information about children’s reading achievement, allowing teachers to compare a child’s performance on a single day with that of a nationally representative sample of children of the same age and to monitor progress over time.

In Ireland, primary schools are required to administer standardised reading tests in specified classes and to communicate these results to parents. Many schools report these results using STen scores because they provide a simple and familiar way of describing a child’s reading attainment. As a result, STen scores have become a common language in conversations between schools and families about children’s reading progress.

The difficulty arises when these scores become something more.

In many schools, STen scores inevitably form a great deal of the conversation when decisions are being made about learning support. Given the reality of finite Special Ed resources, that is entirely understandable. Schools have difficult decisions to make and are often trying to prioritise support among a larger number of children than they have capacity to serve. Standardised test results can and should contribute to those decisions. The concern arises when a STen score becomes the dominant piece of evidence. A standardised reading test tells us how well a child performed compared with other children of the same age. It does not tell us why they performed that way, how efficiently they read, or whether underlying literacy difficulties have been masked by other strengths.

That distinction is important.

Consider two children. One achieves a STen score of 3 and another achieves a STen score of 5. It may seem obvious that the first child should be prioritised for support. However, the second child may have persistent difficulties with decoding, weak spelling, poor phonemic awareness and slow, effortful reading, despite achieving an overall score within the average range.

A single score on a standardised test cannot capture those differences.

The same issue arises at the higher end of the scale. A child with a STen score of 7, 8 or 9 may still experience significant difficulty with spelling, decoding unfamiliar words or developing fluent, automatic word recognition, like my daughter. Strong oral language, good vocabulary, effective memory, supportive teaching and considerable determination can all help a child compensate sufficiently to perform well on a standardised reading test.

If the conversation ends with a reassuring STen score, those difficulties can remain hidden for years. Maybe I too had been reassured by the very evidence that should have prompted more questions.

My daughter’s STen scores told me that she was achieving well in comparison with her peers. What they could not tell me was that reading had never become something she enjoyed or that spelling remained persistently difficult. They could not tell me how much effort reading required or that the increasing literacy demands of secondary school were beginning to affect subjects beyond English.

No standardised test could be expected to tell me those things. That is not what they are designed to do. Standardised reading tests measure attainment. They do not identify dyslexia and they do not, on their own, provide a full account of the processes that underpin a child’s reading. They answer one important question: How is this child performing compared with other children of the same age?

Over the past two decades, our understanding of reading assessment has increasingly moved away from waiting for children to experience reading failure and towards identifying those who may be at risk before difficulties become established. The purpose of early screening is not to diagnose dyslexia but to identify children who may benefit from targeted support and closer monitoring.

That requires different kinds of assessment.

Research consistently identifies phonemic awareness, letter-sound knowledge, decoding, spelling and oral reading fluency as among the strongest indicators of children’s developing reading skills. Difficulties in these areas often emerge long before a child’s performance on a standardised reading test gives obvious cause for concern.

Spelling can be particularly informative. A child may perform well on a reading comprehension test because strong oral language and background knowledge support their understanding of the text. Their spelling, however, may reveal less secure knowledge of phoneme-grapheme correspondences, orthographic patterns and word structures. A mismatch between apparently strong reading attainment and persistently weak spelling should prompt further investigation.

Oral reading fluency can also provide information that a broad standardised score may not capture. A child may answer comprehension questions correctly while reading slowly and effortfully. They may reach the correct answer, but at a considerable cognitive cost. Accuracy alone does not tell us whether reading has become automatic and efficient.

This was the case with my daughter. She could read a passage and answer comprehension questions successfully, but doing so came at a considerable cost. As she got older, while she enjoyed school, I began to notice how exhausted she was after a day at school. It wasn’t unusual for her to come home and fall asleep, something I now recognise as the exhaustion of a child working far harder to read than anyone around her realised. I also became increasingly aware that her spelling was not where I would have expected it to be for her age. Interestingly, one of the things that surprised me most after her diagnosis was that she genuinely considered herself to be a good speller. She was not carelessly making mistakes; she believed the words she had written were correct. And despite growing up in a house filled with books, she never chose to read for pleasure. Taken individually, none of these observations seemed particularly significant. Together, however, they prompted me to seek a formal assessment.

Teacher observation is essential because teachers notice children who avoid reading, whose spelling seems unexpectedly weak, who read accurately but unusually slowly, or who appear to be coping while working considerably harder than their classmates. None of those observations, taken in isolation, tells the whole story. Together, however, they can provide a richer picture than a single standardised test score can offer. Good assessment has always involved bringing together multiple sources of evidence. Teacher observations, classroom assessment, progress monitoring, targeted screening measures and standardised tests all contribute something valuable. Each tells us something slightly different about a child’s reading development.

I have enormous sympathy for schools making decisions about learning support. These decisions are rarely straightforward, particularly where the number of children who could benefit from support exceeds the time and teachers available. My argument is not that STen scores should be removed from the process but that they should not carry the process on their own. Using a single attainment score as a gatekeeper risks missing children whose difficulties are not reflected in their overall reading achievement.

A child does not need to be among the lowest-attaining readers in a class to have a significant literacy difficulty.

What this experience has changed is not my confidence in standardised reading tests. They continue to have an important place in schools. What it has changed is my appreciation of their limits. A standardised reading test tells us something useful about a child’s reading achievement but it does not tell us everything.

My daughter was fortunate. Although her diagnosis came later than I would have liked, we were able to afford a private assessment and eventually found the answers we were looking for. Not every family has that option.

If this experience has reinforced one belief I already held, it is that every assessment tells only part of a child’s story. The challenge is not to place more weight on any one measure, but to bring together multiple sources of evidence through careful assessment and early screening. The sooner we identify children who may be at risk, the sooner we can provide the support they need to thrive. For my daughter, that support has finally come but I would like it to come sooner for the next child whose STen score says one thing and whose story says another.

In my next substack, I will explore what schools might use alongside standardised tests to identify children who may be at risk of reading difficulties. I will look at the evidence for measures such as phonemic awareness, letter-sound knowledge, decoding, spelling and oral reading fluency, and consider how these can contribute to a more complete understanding of a child’s reading development.