Evaluation Report Scores and Distribution Table
Standard Score (SS): A way to compare student performance to a standardization sample. Standard Scores in evaluation reports have a Mean (average) of 100 and a Standard Deviation of + or - 15. A standard deviation (SD) is a measure used to quantify the amount of variation from the Mean. A lower SD indicates a student performing closer to the majority with a higher SD indicating performing much lower or higher than the majority. 66% of students will score between 85 and 115.
Scale Scores: have a score range of 0 – 19 points, with an average score of 10 points. These scores are typically used for “Sub-tests,” which are smaller components of a larger psychological test, such as the WISC-V, the NEPSY-2, or the DKEFs.
T Scores: are standardized scores on each dimension for each type. A score of 50 represents the mean. A difference of 10 from the mean indicates a difference of one standard deviation. Thus, a score of 60 is one standard deviation above the mean, while a score of 30 is two standard deviations below the mean.
Percentile Rank: of a score is the percentage of scores in its frequency distribution that are equal to or lower than it. For example, a test score that is greater than 75% of the scores of people taking the test is said to be at the 75th percentile rank. Percentile ranks are not on an equal-interval scale; that is, the difference between any two scores is not the same between any other two scores whose difference in percentile ranks is the same.
Common Language and Descriptions for Scores in Evaluation Reports