Issue 22: Navigating Cut-Point Scores for Diagnosis of Dyslexia | Challenges and Recommendations | Dr Jen O'Sullivan

My eleven-year-old nephews are identical twins with an inseparable bond. Chatty, funny, and charming, they are best friends. They share the same class in school and enjoy the same sports and clubs. When my brother built an extension onto their house last year, giving each their own room, it took only days before they decided to move back in together, preferring the comfort of each other's company. Last year, their parents became concerned about their progress in school and noticed they were becoming more anxious about attending school. They arranged for a private assessment by an educational psychologist. The evaluation revealed that one of the twins had dyslexia, while his brother's scores placed him just marginally above the cut-point threshold. For the first time, the twins faced a difference that set them apart in their shared journey.

The Importance of Cut-Point Scores

Developmental dyslexia is a complex disorder that involves genetic, neurological, and environmental factors (Catts & Petscher, 2018). It is a specific learning disability affecting reading and related language-based processing skills and requires early identification and intervention to ensure that targeted support is intensively and explicitly delivered. The complexity of the disorder is reflected in the fact that there is still no single, agreed-upon definition of dyslexia. This lack of consensus on what dyslexia is may stem from difficulties in measuring it. One important aspect in identifying dyslexia is the establishment and use of cut-point scores. These scores serve as benchmarks in assessments to determine whether a child meets the criteria for a diagnosis of dyslexia. The establishment of appropriate cut-point scores ensures that children who need help are accurately identified to receive the necessary interventions to make learning more manageable. Consequently, the establishment and use of cut-point scores can greatly affect a child's educational trajectory.

Determining Cut-Point Score

Cut-point scores for dyslexia are established through a meticulous process involving both statistical analysis and expert judgement. Initially, standardised reading assessments, such as the Woodcock-Johnson Tests of Achievement and the Comprehensive Test of Phonological Processing (CTOPP), are administered to a representative sample of the population. These assessments evaluate various components of reading, including phonological processing, decoding, fluency, and comprehension. Researchers then analyse the normative data from these assessments to determine the typical range of scores for specific age groups. Using this data, they identify thresholds or cut-off points that distinguish between typical readers and those who perform significantly below the norm, indicative of dyslexia. The establishment of these cut-point scores involve expert judgement to balance sensitivity (the ability to correctly identify those with dyslexia) and specificity (the ability to exclude those without dyslexia), ensuring that the criteria are neither too lenient nor too strict. This process is highly complex and needs to be regularly reviewed and adjusted to remain relevant and accurate as educational standards and population demographics evolve.

Downside of Cut-Point Scores

The use of cut-point scores to diagnose dyslexia has notable downsides, primarily due to the rigid nature of these thresholds. They create a binary situation where children are either diagnosed with dyslexia or not, which can oversimplify the spectrum of reading difficulties, as in the case of my nephews. Children who score just above the cut-point still struggle significantly and need very similar interventions, but they may not receive the necessary support because they do not meet the criteria for a diagnosis. This binary situation can also lead to feelings of confusion and inadequacy in those who have just missed the cut-point score for dyslexia, potentially impacting their self-esteem and motivation. Furthermore, the reliance on a single assessment moment may not capture the full picture of a child's reading abilities on that day, especially since factors such as test anxiety, fatigue, or external distractions can affect performance. Therefore, more comprehensive, ongoing approaches to the assessment of reading difficulties that consider a range of skills and behaviours would ensure all students receive the appropriate interventions they need to succeed.

Cut-point scores for diagnosing dyslexia are arbitrary in nature, reflecting the complexities and limitations of attempting to standardise a multifaceted learning disability, as the determination of thresholds involves subjective judgement from experts, who must balance sensitivity and specificity to avoid misdiagnosis (Mather & Wendling, 2012). This process means that slight variations in the cut-off points can significantly affect who is identified as having dyslexia and who is not, emphasising the arbitrary nature of these scores (Pennington, 2006). The thresholds do not account for the individual differences and contextual factors that influence reading abilities, such as socioeconomic background or additional learning difficulties (Elliott & Grigorenko, 2014). Consequently, reliance on cut-point scores alone can lead to inconsistencies in diagnosis and support, highlighting the need for a more nuanced and comprehensive assessment approach.

Recommendations

Educational policies need to prioritise a continuous support system where interventions are based on specific needs rather than rigid thresholds. Schools could adopt a tiered support model, offering different levels of assistance depending on the severity of reading difficulties, regardless of whether a formal diagnosis is made. This approach would ensure that all children, especially those on the borderline, receive the help they need to thrive academically. In addition, the following recommendations are made:

1. The Utilisation of Multiple Measures: Relying on a single assessment can lead to inaccurate identification. Combining results from multiple tests provides a more comprehensive understanding of a student's reading abilities. This approach minimises the risk of misidentification and ensures that interventions are tailored to a student's specific needs (Snowling & Hulme, 2012; Wagner, 2018).
2. Periodic Review and Adjustment: Cut-point scores should not be static. Regularly reviewing and adjusting them based on new research and changing populations ensures they remain relevant and accurate. This practice helps accommodate variations in educational standards and demographic shifts (Mather & Wendling, 2012).
3. Professional Judgement: While statistical data is critical, the insights of experienced educators and psychologists are invaluable. Professional judgement should complement data to consider contextual factors that might affect a student's performance, such as socioeconomic background, language proficiency, and family history (Elliott & Grigorenko, 2014).
4. Training for Educators: Educators should receive ongoing training on how to interpret and use cut-point scores effectively. Understanding the nuances of these scores could help educators identify at-risk students more accurately and implement appropriate interventions promptly (International Dyslexia Association, 2019).
5. Focus on Early Identification: The earlier dyslexia is identified, the better the outcomes for the student. Implementing assessments for younger students, even as early as kindergarten, can facilitate early intervention, which is critical for improving reading skills and academic success (Shaywitz et al., 2008).

Conclusion

In conclusion, navigating cut-point scores for dyslexia diagnosis presents both challenges and opportunities for improvement in educational practices. While these scores play a crucial role in identifying dyslexia and directing interventions, their inherent rigidity can overlook nuanced reading difficulties that fall just outside defined thresholds, as exemplified by my nephews. Rightly or wrongly, a diagnosis of dyslexia often unlocks a wealth of ongoing support within educational systems. For one of the twins, his world is opening up with tools and strategies that help make learning more manageable. Meanwhile, his brother, who struggles almost just as much with aspects of working memory, processing speed, and reading, must rely on the limited support his overworked classroom teacher can provide. One twin has had the challenges he is experiencing explained to him, giving him a sense of understanding and direction, while the other is left wondering why he does not receive the same support or why he is not considered as having dyslexia. To address these limitations, it is essential to advocate for a more flexible and comprehensive approach to assessment. This includes adopting multiple measures of reading ability, regularly reviewing and adjusting cut-point scores, incorporating more professional judgement alongside statistical data, and providing ongoing training for educators in the identification of children who are experiencing reading difficulties. By embracing these recommendations, educational systems can better meet the diverse needs of both learners with dyslexia and those falling marginally outside of the threshold.

References

• Catts, H.W., & Petscher, Y. (2018). Early identification of dyslexia: Current advancements and future directions. Perspectives on Language and Literacy, 44, 3, 33-36
• Elliott, J. G., & Grigorenko, E. L. (2014). The Dyslexia Debate. Cambridge University Press.
• International Dyslexia Association. (2019). Dyslexia in the Classroom: What Every Teacher Needs to Know. [dyslexiaida.org]
• Mather, N., & Wendling, B. J. (2012). Essentials of Dyslexia Assessment and Intervention. Wiley.
• Pennington B. F. (2006). From single to multiple deficit models of developmental disorders. Cognition, 101(2), 385–413. [doi.org]
• Shaywitz, S. E., Shaywitz, B. A., Fletcher, J. M., & Escobar, M. D. (2008). Prevalence of Reading Disability in Boys and Girls. Journal of the American Medical Association, 264(8), 998-1002.
• Snowling, M. J., & Hulme, C. (2012). The Science of Reading: A Handbook. Wiley-Blackwell.
• ​​Wagner, R.K. (2018). Why is it so difficult to diagnose dyslexia and how can we do it better? The Examiner, 7. Washington, DC: International Dyslexia Association. [dyslexiaida.org]

Dr Jen O’Sullivan

Dr Jen O'Sullivan is an assistant professor in literacy education at the Marino Institute of Education. She is the author of the phonological awareness programme A Sound Beginning for Reading and co-author of the phonics programme Sounds Like Phonics. She is an executive committee member and past president of The Literacy Association of Ireland and is a research fellow in the School of Education at Trinity College Dublin. In 2022, she was the recipient of a Fulbright Scholarship Award, where she spent three months visiting the Florida Center for Reading Research at the Florida State University.

Extracts from Dystinct Magazine