Normal Curve Equivalent (NCE)
NCE scores range from 1–99 and align with PR scores at 1, 50, and 99. The NCE scale is an equal-interval scale (which allows NCE scores to be treated arithmetically), while the Percentile Rank (PR) scale is not. NCE will always be set so that the mean is 50, no matter the grade level of the test. The average student in the United States will be a better reader in grade 5 than in grade 4, but an average student would have an NCE 50 in grade 4 and a 50 in grade 5.
Equal-interval scales let you make meaningful score comparisons among different achievement tests, and are especially useful in measuring group or individual gains and losses in achievement. For example: in a normally distributed population, if all students make exactly one year of progress after one year of instruction, their NCE scores would remain exactly the same—even if their Scaled Score increased, their NCE gain would be 0. A student with a positive NCE gain score would have improved more than the average student; a student with a negative score would have learned less than the average student.
Normal Curve Equivalents can be found in the following reports: