What do the numbers in a psychoeducational evaluation mean?
As a parent faced with the pages and pages of numbers that often accompany a psychoeducational evaluation, it can be overwhelming and complicated to try to make sense of the all the numbers and what those numbers mean for your child. A good psychoeducational evaluation should be very clear in interpreting the numbers and explaining their relevance. In my many years, I have seen quite a few reports that fall short on this measure. I frequently field questions about the meaning of these numbers. So here goes:
The results of a psychoeducational assessment are presented in a different numbering system with which teachers and parents are generally not familiar. The raw scores on any assessment are converted to scaled scores and standard scores (less often scores are reported as T scores). The conversion to these scaled and standard scores allows comparison of performance on a variety of assessments because the statistics behind them are the same. We do not use grade equivalent scores because they are basically useless and are not considered to be “good” statistics. Most scaled and standard scores are age based, indicating that the performance of the student is being compared with other children within a narrow similar age range. (The developmental component is critical since child development is a very significant factor in our expectations of a child).
So what are scaled and standard scores and how do you understand them?
These scores are presented on subtests of a battery. Scaled scores range from 1-19 with an average score of 10 and the average range is 8-12. Scores of 13 and 14 are high average, while a score of 15 is superior. Scores of 16 and above are considered very superior. On the lower end of the range, a score of 7 is low average, while 5-6 is considered borderline, and a score of 4 and below is impaired. Children with a score of 7 or below will have varying degrees of difficulty with the tasks that resulted in that score. Here it is again in a more visually-friendly format:
4 or less= IMPAIRED
7= LOW AVERAGE
13-14= HIGH AVERAGE
16 or more= VERY SUPERIOR
Scaled scores are converted to standard scores when subtests are compiled for overall performance. The standard scores range from 50-150 with an average of 100. The average range includes scores from 90-110, while high average ranges from 111-120. Superior scores are 121-129 and scores above 130 are considered very superior. The low average range includes scores from 80-89, while borderline is considered 70-79. Below 70 is considered impaired, and those scores are delineated as mild, moderate, severe and profound.
Reports often also contain percentile scores, which are also comparable from test to test. Percentiles represent a child’s performance relative to other children the same age, and can be interpreted as “ child at the 49th percentile performed better than 49 children the same age, implying that 51 children performed at a higher level”. The average range for percentiles ranges from the 16th percentile to the 84th percentile.