Explanation of CAT scores
Several different numbers are listed on your California Achievement Test results sheet. Most of these are calculated based on a norm group (the original group of students tested on which the test is standardized). Results are listed by academic area. Below are basic definitions for these scores.
Raw Scores
Raw scores are the actual number of correct answers within a given test section, and are used to calculate the Grade Equivalent, Percentile, and Stanine results. They should not be used for any kind of comparison or statistical calculation since each test section varies in the difficulty and number of questions.
Grade Equivalent Scores
Grade equivalent scores represent the grade level (year and month separated by a decimal point) of a student’s ability compared to the median score of students at the same academic level.
Scores that are above a student’s grade level do not by themselves indicate proficiency to skip to the next grade level in the particular academic areas. These scores more likely show an understanding of only some of the concepts of that higher grade. Conversely, scores below a student’s grade level may indicate a gap of understanding in those academic areas. Scores equal to a student’s grade level are considered the minimum for grade level ability.
Percentile Scores
Percentile scores are equivalent to the percentage of students from the norm group who received lower scores than the student. For example: a student with a percentile score of 73 means that the student did better than approximately 73 percent of the students in the norm group. Percentile scores do not represent the number of questions answered correctly.
Percentiles are useful for comparing a student’s performance over several sections on the test. However, because they are not measured on an equal scale of units, they are not suitable for most statistical calculations.
Stanine Scores
Derived from the term STAndard score from a NINE-unit scale, stanines are based on the mean of the norm group (who are given the score of 5) and a standard deviation of 2.0. Scores are determined by the amount of standard deviation from the norm group, in approximately one-half standard deviation increments.
The following lists the meaning of each score:
9 – Highest level
8 – High level
7 – Well above average
6 – Slightly above average
5 – Average
4 – Slightly below average
3 – Well below average
2 – Low level
1 – Lowest level
Stanine scores are useful in calculating means, correlation coefficients, and other statistics which are meaningful to test evaluators.