Terms and Abbreviations
GRADE EQUIVALENT (GE)
The Grade Equivalent is a number that describes a student's location on an achievement continuum. Grade Equivalents are expressed in terms of grade and months into grade, assuming a 10-month school year (e.g., 8.4 means after 4 months of instruction in the 8th grade). The Grade Equivalent corresponding to a given score on any test indicates the grade level at which the typical student obtains this score. Because of this, Grade Equivalents are not based on an equal interval scale, and therefore cannot be added, subtracted, or averaged across test levels the way other scores can (scale scores or standard scores).
Interpretations/Cautions of Grade Equivalent Scores: If a sixth-grade student obtains a GE of 8.4 on the Vocabulary Test, his/her score is like one a typical student finishing the fourth month of eighth grade would likely get on the Vocabulary Test. Grade Equivalents are particularly suited for estimating a student's developmental status or year-to-year growth. These scores are not particularly suited for identifying a student's standing within a group or for diagnosing areas of relative strength or weakness. Grade Equivalents do not provide a prescription for grade placement. For example, a fourth-grade student earning a GE of 6.2 on a fourth-grade reading test obviously demonstrates that his/her developmental level in reading is high relative to his/her fourth-grade peers. However, the test results supply no information about how well he/she would handle the material normally read by students in the early months of sixth grade. Therefore, it cannot be concluded that he/she is ready for placement in the sixth grade.
NATIONAL PERCENTILE RANK (NPR)
A Percentile Rank indicating the status or relative rank of a student's score compared to a nationally representative sample of examinees. For additional details see Percentile Rank.
NATIONAL STANINE (NS OR STA9)
A stanine score indicating the status or relative rank of a student's score compared to a nationally representative sample of examinees. For additional details see Stanine.
PERCENTILE RANK (PR)
The percentage of scores in a specified distribution that fall at or below the point of a given score. Percentile Ranks range in value from 1 to 99, and indicate the status or relative standing of an individual within a specified group (e.g., norms group), by indicating the percent of individuals in that group who obtained lower scores. For example, if a student earned a 72nd Percentile Rank in Language, this would mean he or she scored better than 72 percent of the students in a particular norm group who were administered that same test of Language.
The 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 or equal to 75% of the scores of people taking the test is said to be at the 75th percentile, where 75 is the percentile rank. Note: an individual's percentile rank can vary depending on which group is used to determine the ranking. A student is simultaneously a member of many groups: classroom, grade, building, school district, state, and nation. Test developers typically publish different sets of percentile ranks to permit schools to make the most relevant comparisons possible.
STANDARD SCORE (SS)
Standard scores are continuous across all levels and forms of a specific test. Because they are built on equal-interval scales, the magnitude of a given difference between two scores represents the same amount of difference in performance wherever it occurs on the scale. For example, the difference between standard scores of 15 and 20 is the same as the difference between standard scores of 45 and 50.
The name stanine is simply a derivation of the term "standard-nine" scale. Stanines are normalized standard scores, ranging in value from 1-9, whose distribution has a mean of 5 and a standard deviation of 2. Stanines can, more easily, be thought of as coarse groupings of percentile ranks, and like percentile ranks indicate the status or relative rank of a score within a particular group. Due to their coarseness, stanines are less precise indicators than percentile ranks, and at times may be misleading (e.g., similar PR's can be grouped into different stanines [e.g., PR=23 and PR=24] and dissimilar PR's can be grouped into the same stanine [e.g., PR=24 and PR=40]). However, some find that using stanines tends to minimize the apparent importance of minor score fluctuations, and are often helpful in the determination of areas of strength and weakness.