My school year starts with speech-language and hearing screenings of preschool through first-grade students. Then come meetings with teachers and recommendations for evaluations, if needed.
Parents generally get anxious when we recommend an evaluation and are further overwhelmed when they see a report with lots of numbers or tables. We forget that many of the statistical terms speech-language pathologists and educators use regularly remain a mystery to most. So in my post-testing conference, I give an overall description of the tests administered and explain various subtests along with offering fictional examples.
Then it’s time for a brief statistics lesson to help parents understand the numbers:
Raw score: I don’t typically include this information, but it’s helpful if a parent understands that the raw score is simply the number of questions the student answered correctly on the test or subtest.
Age equivalencies: This is the first number that sets parents’ hearts racing. I always quickly explain that it isn’t the best representation of performance. Age equivalents reflect the average ages at which a raw score is achieved. This means half of children that age score below this number and half above, so it doesn’t demonstrate the range of normal performance.
I also tell parents that age equivalencies don’t reflect consistency of performance and simply provide a different representation of the raw score. A young child might get to the 2oth question before the test ends and receive a raw score of 17, for example, while an older student might get to the 35th question and still have a raw score of 17. Both receive the same age-equivalency score. However, to me, the child who answered more questions demonstrates more advanced skills, although the performance also shows holes or inconsistencies.
Standard Scores: With these numbers, I pull out paper and draw the bell curve. I place the mean at the highest point (usually 100) and make sure parents understand that these standard scores give us a range of normal for comparison with the mean as the average score. I reiterate that the mean score doesn’t reflect perfect performance, a common confusion once they spot the 100. Next, I show them where their child falls along the curve and how many standard deviations it is from the mean. If needed, I show at what point their child qualifies for services.
I may also mention that standard scores are one of the ways we measure progress over time. For students receiving an entire educational evaluation, I also explain how we use standard scores as a point of comparison to judge relative strengths and weaknesses.
Percentile ranks: This is another stat that tends to concern parents and again, I use the bell curve, this time to match percentile rank with standard scores. Many parents see a percentile rank of 47 and panic, thinking this means their child got 47 percent of the questions correct, which to them means a “failing” grade! It’s important we clarify that a percentile rank is not a percentage grade and that a 47 means nearly half of the students taking that test scored the same as their child.
While math, statistics especially, can seem scary, it’s critical that parents receive all the information we collect and a thorough explanations of what the numbers mean. The beauty of statistics is that using numbers along with a quick illustration puts understanding within the grasp of most anyone.
Kimberly Swon Lewis, MEd, CCC-SLP, is a pediatric SLP in Greensboro, North Carolina, and the author of the Activity Tailor blog. To view the original post and download a free parent handout, click here. firstname.lastname@example.org.