Friday, January 23, 2009

Reading and dyslexia: Should RAN run and hide?

I just read an excellent article that investigated the relative importance of phonological awareness, naming speed (RAN-rapid automatized naming), orthographic knowledge, and morphological awareness in understanding reading achievement. Although caution is in order given the total sample size (n=93), this study is an excellent example of the type of research we need more of in educational psychology. great feature of the article is the description and definition of the four different reading-related constructs that have recently become recognized as important in learning to read. I would recommend reading the introduction just to better one's understanding of phonological awareness, etc.

However, my real excitement for this article is that it directly attempts to deal (at least partially) with the problem of specification error, a type of research design error that occurs when potentially important variables in predictive or explanatory studies are omitted. This type of error can lead to biased estimates of the effects (relative importance) of predictive variables. I've soap-boxed about this before and will not repeat my lengthy diatribe here. Long story short - I believe that much of the "hot" reading/dyslexia research that has recently dominated the educational, special education, and school psychology fields may have too quickly anointed some emperors (phonemic awareness; RAN) and gave them too much credit. Read my prior post at the link above. Unless you've been living under a rock (and you work with kids with reading problems), it seems like there is constant chatter about "RAN this...RAN that...RAN is it....etc." Yes....I am exaggerating to make my point.

Why do I like this current article (or why does it soothe my ranting a tad)? Simple. It did not just study RAN and/or phonemic awareness in isolation as predictors of allowed them to compete for the explanation of reading together with orthographic knowledge and morphological awareness. And guess what? RAN failed to place in the race! When entered in a simultaneous regression model to predict reading, RAN added nothing to the prediction of reading when phonemic awareness, orthographic knowledge, and morphological awareness where also in the running.

This article suggests that the hype around RAN may have been over-exaggerated, due to specification error in a ton of the hot and sexy reading research that has dominated our professional journals and conferences this past decade.

But don't get me wrong, there is a good body of evidence that suggests that the processes underlying RAN are probably important for early reading. My point, which is buttressed by this article, is that maybe it has been given too much credit....and needs to be knocked down a notch.

I would be remiss if I did not also criticize this current study for also failing to include other potentially important predictors of reading. For example, I would have liked to see the authors also include measures of working memory (Gsm-MW), lexical knowledge (Gc-VL) or vocabulary, perceptual speed (Gs-P), and associative memory (Glr-MA)....based on my reading of the extant reading literature.

I will now get down from my specification error soap box. The take away message is that we need more studies that take off the blinders and include a more comprehensive array of research-based indicators of important constructs related to reading (and all areas of school learning) we can ascertain which constructs/abilities are important, and to what degree. Also...I would prefer if these researchers had specified a research- or theoretically-based causal SEM model (with possible direct and indirect causal paths between the constructs)---maybe RAN would be seen as being more important...possibly as a direct or indirect cause (or outcome) of the other predictors.

Below is the article reference, abstract and link for your reading.

Roman, A. A., Kirby, J. R., Parrila, R. K., WadeWoolley, L., & Deacon, S. H. (2009). Toward a comprehensive view of the skills involved in word reading in Grades 4, 6, and 8. Journal of Experimental Child Psychology, 102(1), 96-113. (click here to view/read)

  • Abstract: Research to date has proposed four main variables involved in reading development: phonological awareness, naming speed, orthographic knowledge, and morphological awareness. Although each of these variables has been examined in the context of one or two of the other variables, this study examines all four factors together to assess their unique contribution to reading. A sample of children in Grades 4, 6, and 8 (ages 10, 12, and 14 years) completed a battery of tests that included at least one measure of each of the four variables and two measures of reading accuracy. Phonological awareness, orthographic knowledge, and morphological awareness each contributed uniquely to real word and pseudoword reading beyond the other variables, whereas naming speed did not survive these stringent controls. The results support the sustained importance of these three skills in reading by older readers.
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