Standard score
Last updated
A standard score shows how far a student's test result is from the average of the norm group, usually on a scale where 100 is average.
Topic: Evaluation and assessment
In plain terms
On most cognitive and achievement tests, standard scores have a mean of 100 and a standard deviation of 15. That means about two-thirds of students score between 85 and 115. A score of 70 is two standard deviations below average; a score of 130 is two above. Some tests use other scales, such as scaled scores with a mean of 10, so always check the report's key.
How it shows up in an IEP
Standard scores appear in evaluation reports and help the team see the size of a gap. Because they compare with peers, a student can learn a great deal and keep the same standard score, which is why goals use direct skill measures.
Example
A math calculation standard score of 78 tells the team the student is well below average for age. The goal itself measures digits correct per minute on grade-level probes.
Related terms
- Percentile rankA percentile rank tells the percent of students in the norm group who scored at or below a student's score.
- Norm-referenced testA norm-referenced test compares a student's score with the scores of a large group of same-age or same-grade students who took the test earlier.
- Grade equivalentA grade equivalent is a score that matches a student's raw score to the grade level at which an average student earned the same raw score.
- Evaluation (special education)A special education evaluation is the set of assessments a school uses to decide whether a child has a disability and what services the child needs.
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