A Caution About Composite Scores

When children struggle with reading it’s important that we evaluate them to determine why they are having trouble, what part of the reading process is problematic for them, where they lie on a continuum of reading disabilities and what can be done to help them achieve reading success.

A good evaluation includes an analysis of the student’s performance supplemented with discussion of test scores.

It is particularly important to properly interpret composite scores when analyzing  student performance.  A composite or cluster score is a score that is constructed by combining individual test scores. When  individual tests within the composite are not similar a composite score can obscure identification of a reading problem.  The use if these scores may lead to misinterpretation of the underlying issues when trying to understand why a child is having trouble learning to read.

Lets look the Woodcock-Johnson IV (WJIV) as an example of how this might play out.  The WJIV is a standardized test battery with many individualized tests. It  is commonly used by schools and evaluators.  Let’s assume that Casey obtained the following test scores:

  • He scored in the 2nd percentile on the Letter-Word Identification test (a test of word list reading).  This is a very low score and indicates that 98% of the population scored better than he did.
  • He scored in the 16th percentile on the Sentence Reading Fluency test (a test of his reading fluency). His performance on this test indicates that 84% of the population scored higher than he did on this test.
  • He scored on the 84th percentile on the Passage Comprehension test (a test of reading comprehension).  This tells us that he has scored higher than 83% of the population.

Based on these scores, it appears that Casey has significant difficulty reading words that are not in context and his reading is slow. On the other hand, while Casey may struggle with decoding, he did well on a test of reading comprehension.

Evaluators can combine these three scores to create a composite score called Broad Reading.  Are you following what will happen here?  Casey’s Broad Reading score will be misleading because the combined score doesn’t tell the whole story!  Since Casey’s performance is very different on the three tests, his Broad Reading score tells us nothing about his actual reading ability.  If we use his Broad Reading score, Casey will appear to be a low average reader and may not qualify for reading help.

You can see the importance of understanding how scores are used.  Ask your evaluator to identify the composite scores in the report and to point out the scores that comprise that score.  Have individual test scores been used to identify your child’s problem with reading?

By |January 25th, 2017|Dyslexia|0 Comments