Grade Equivalent Scores

Grade equivalent scores are norm-referenced, developmental scores. They are most frequently reported for achievement tests. Grade equivalent scores compare an individual's score to those of a norm group comprised of students attending the same grade in school as the individual whose score is being reported. For example, developmental scores may be expressed as 5.6 or 5–6 and interpreted as the average scores of fifth graders at the sixth month of fifth grade. Some grade equivalent scores are the mean score; others are the median score. The technical manual for the test indicates which measure of central tendency (i.e., mean or median) was used to determine grade equivalent scores reported. Grade equivalent scores are widely used in schools, but they are very difficult to interpret because they do not have good psychometric properties.

There are several guidelines for interpreting grade equivalent scores. Norm-referenced grade equivalent scores should not be confused with standards of acceptable or desirable grade-level performance. Grade equivalent scores are average scores. At any particular grade level, approximately 50% of the students will score above the grade equivalent score and 50% will score below it. For this reason, it is not reasonable for a school district to expect all of its students to be at or above grade level on a norm-referenced score. Norm-referenced scores indicate achievement relative to a particular norm group of students at a particular grade level. They do not indicate the level at which students should be performing.

A grade equivalent is not an estimate of the grade at which the student is working or should be placed. Students complete test items designed for the curriculum taught at the grade level in which they are enrolled. Grade equivalent scores that exceed the grade level of the student indicate that the student knows grade-level material better than most students at the grade level. For instance, the fourth-grade student who earns a grade equivalent score of 7.3 on a reading subtest understands fourth-grade reading material very well. The score does not mean that the student could or should be assigned seventh-grade reading material. The same principle applies to a fourth-grade student who earns a grade equivalent score of 2.1. The student likely has difficulty reading fourth-grade material. The score does not mean the student should be reading third-grade material or that the student can only read third-grade material.

Most nationally norm-standardized achievement tests provide grade equivalent scores for a series of tests. Grade equivalent scores on different subtests of the same test are not comparable because grade equivalent scores do not have equal units of measurement. That is, a grade equivalent score of 5.1 on a social studies subtest is not necessarily higher than a grade equivalent score of 4.2 on a science subtest. If students, teachers, or parents wish to compare scores on different subtests of the same achievement test or the same content areas from different achievement tests, they need to make the comparisons based on percentile ranks or standard scores.