Copyright # 2002 John Wiley & Sons, Ltd. DYSLEXIA 8: 53–54 (2002)DOI: 10.1002/dys.210

& Letter to the Editor

Dear Editor,

I was interested to note the response by Rea Reason to Ann Cooke’s letterconcerning the report of the working party of the DECP of the BPS on dyslexia,literacy and psychological assessment. Many people working in dyslexia,including the British Dyslexia Association, were concerned about the definitionof dyslexia being ‘‘where word reading and spelling develops very incompletelyor with great difficulty ’’. The BDA produced a response to this definition. Thereare, however, a number of other issues that are also important that arise from thisparticular report.

One of these is the notion of a discrepancy model of assessment of dyslexia.That is, that it is possible to:

(1) set a predicted or expected attainment age, usually reading or spelling, forchild’s chronological age and intelligence.

(2) look at the actual reading and spelling age.(3) make a statistical and clinical inference about this ‘discrepancy’.This was the fundamental breakthrough in the recognition of dyslexia in the

late 1970s, following the Tizard report and the I.O.W. study examining thedifferences between children with ‘general reading difficulties’ and ‘specificreading retardation.’

This theme has subsequently been taken up by both the WISC III and theBAS II, where there are very specific means to make predictions of attainmentsbased on IQ. The DECP report (37 pp. and following) is critical of this approach,arguing from a number of quoted theoretical positions that it is difficult tomeasure intelligence, makes the assumption that the core phonologicaldifficulties are major diagnostic criteria and argues that one can look at adiscrepancy between comprehension in reading and reading decoding (beggingthe question of how one defines comprehension } is that not also part of anintelligence test score?) as well as a number of other important issues. I havediscussed these elsewhere (Thomson, 2000, 2001), but there are some veryimportant practical implications arising from the rejection of a discrepancy modelof assessment.

One of these is the increasing comments by Educational Psychologists who areinvolved in undertaking Statements of Special Educational Needs for dyslexicchildren. Recently, those attending East Court School for reviews of children statethat intelligence should not be used as a factor in deciding what level of specialeducational need provision a given dyslexic child might need. They quote theBPS Report in support of this argument. Obviously, if one defines dyslexia assimply poor reading decoding, then only those children whose reading levels fallbelow the second centile based on their chronological age are eligible forspecialist schooling provision or equivalent. Note that the second centile is thegenerally accepted, albeit arbitrary, cut off point used by many LEAs. On theother hand, if one makes a prediction based on expected reading performance ina child who has above average or high IQ, one might come to a different

conclusion as to just how far behind they were in their written language skill. Asit is, the definition given by the working party is vague as to when dyslexia isevident i.e. ‘very incompletely’ or ‘with great difficulty’. I’m afraid the reality atthe chalk face is that this means less children are being identified as havingspecific learning difficulties and appropriate provision is not being made. Inmany ways, it is like going back to the 1970s where children are identified ashaving general reading difficulty.

Again, the theoretical issues have been explored elsewhere (Thomson, op. cit.),but it is noticeable that a major assessor of children with potential dyslexicdifficulties, the Dyslexia Institute, also takes the view that a discrepancy analysisis an important part of the overall assessment process (Turner, 1997; Townendand Turner, 2000). Assessments undertaken by the DI are administered byEducational Psychologists, many of whom are using a discrepancy model.

Two further issues that arise from this working party report are theimplications that:

(1) a core phonological deficit is the only really acceptable theoreticalperspective (although it is true that a number of different approaches werereviewed and discussed).

(2) the ACID profile is irrelevant to diagnosis.Rea Reason comments that ‘‘we, the authors, had not managed to make our

meanings clear enough’’. I think that may well be the case, and perhaps furthercomments through this Correspondence Section of Dyslexia would be welcome.

Michael Thomson

References

Thomson, M.E. (2000) Definitions and Discrepancies in Dyslexia. Dyslexia Review, 11(4).

Thomson, M.E. (2001) The Psychology of Dyslexia: A Handbook for teachers. Whurr: London,Chapter 4.

Townend, J. and Turner, M. (Eds) (2000) Dyslexia in Practice: A Guide for Teachers, Chapter 4,Klewer/Plenum: London.

Turner, M. (1997) Psychological Assessment of Dyslexia. London: Whurr.

M. Thomson54

Copyright # 2002 John Wiley & Sons, Ltd. DYSLEXIA 8: 53–54 (2002)