At a glance
In evaluation reports, testing results are presented statistically.
Knowing the terms used in the report helps you understand the results.
Your child’s test scores are only one part of the evaluation results.
Your child is going through the evaluation process. Once the testing is done, you’ll get a report explaining the scores. The results of evaluation testing are presented statistically. So, when you get the report, you may see language you’re not familiar with.
Understanding those terms and concepts can help you understand what your child’s test scores mean. Learn more about the language used to present your child’s testing scores.
Common terms and concepts
Norm-referenced: A test that’s norm-referenced compares your child’s scores to the scores of a large, random group of kids who’ve taken the same test. This “norm group” may be kids of the same age or in the same grade, and their scores are used to determine what’s typical.
For example, on the Wechsler Intelligence Scale for Children (WISC), the average score is 100. So, your child’s score will be based on that.
Test reliability: A “reliable” test provides the same results every time. That means if your child took the test a few times over a period of time, the scores would be roughly the same. For example, say your child took an IQ test in second grade and again in third grade. If it’s a reliable test, the scores should be similar.
Longer tests tend to be more reliable than short ones. That’s because each question is worth more on a shorter test. If a test has five questions and your child gets one wrong, the score will be an 80 percent. But if a test has 20 questions and your child gets one wrong, the score will be a 95 percent.
Standard score: Most educational tests have standard scores based on a scale that makes the average score 100 points. But average is actually a range. There’s wiggle room in test scores to account for possible mistakes. This is sometimes called “standard error.” Standard error allows us to say how confident we are that a score falls within a certain range. Strong tests typically have a lower standard error.
Standard deviation (SD): This is the average distance between all test scores and the average score. Take the WISC-V, with an average score of 100. Most kids fall in the range of 85–115 points. That’s a standard deviation (SD) of 15 points.
Being one SD away (15 points) is still considered average. That gap isn’t big enough to be statistically significant. But a score that’s two standard deviations (30 points) away in either direction is significant because there’s a greater chance that this score isn’t due to chance or error.
Percentile: The percentile shows the proportion of scores that were lower than your child’s score. Let’s say your child is one of 100 kids being tested, and scores in the 75th percentile. That means your child scored higher than 75 of the 100 kids tested.
Many tests are made up of a number of short tests that look at different skills. Those short tests are called subtests. An achievement test may have subtests for vocabulary, working memory, and visual reasoning. Each subtest has its own score.
Sometimes the scores of subtests that look at different pieces of bigger skills are combined. For example, a vocabulary subtest and a language comprehension subtest might be combined to give a “verbal ability” score.
Subtest scores are important. When there’s a big difference between the scores of different skill groups, it can show the specific area in which your child is having difficulty.
What results might look like
The evaluation report will often have a chart that shows the different types of scores. It will include information about the reliability of the test and the standard deviations. But it may also have a written interpretation of the results.
For example: Jane obtained a standard score of 85 (-1 SD) on the WISC, which is ranked at the 16th percentile and is classified as low average. This means Jane’s score was below the average score of 100. She scored the same or higher than 16 percent of kids her age in the general population. While her score is still considered to be average, it’s at the low end of the average range.
Putting it all together
Scores alone don’t tell you what’s going to help your child. The summary and recommendations are where all the information comes together and the evaluator tells you what it means. This section of the report helps answer these questions:
- What does this mean for your child’s ability to learn?
- Do these results show that your child has learning differences that require specialized instruction or other supports?
- What types of services, ways of teaching, assistive technology, and other support could benefit your child? If your child is eligible for special education services, the Individual Education Program (IEP) team will consider the answers to these questions.
Getting your child’s evaluation results can be stressful and confusing for many parents. But knowing what they mean can help you understand exactly why your child is struggling. And it lets you play a more active role in getting the right types of help at school.
Many tests have a range of scores that are considered average.
Subtests help show the specific skills your child has trouble with.
You can use the recommendations of an evaluation report to find ways to help your child learn more successfully.
About the author
About the author
Gail Belsky is executive editor at Understood. She has written and edited for major media outlets, specializing in parenting, health, and career content.
Andrew Kahn, PsyD is a licensed psychologist who has served as an evaluator and consultant in public schools for nearly 20 years. Kahn, who describes himself as neurodivergent, is a subject matter expert at Understood.