NCE Explanation

During the fall of each year students in grade 2 thru 11 in the Quincy Public Schools are given the Stanford 10 Achievement Test.  The scores are reported to parents as NCE (Normal Curve Equivalent) scores.

The Normal Curve Equivalent, or NCE, is a way of measuring where a student falls along the normal curve. The numbers on the NCE line run from 1-99, similar to percentile ranks, which indicate an individual’s rank, or how many students out of 100 had a lower score.  NCE scores have a major advantage over percentiles in that they can be averaged.  That is an important characteristic when studying overall school performance, and in measuring school-wide gains and losses in student achievement.


In a normally distributed population, if all students were to make exactly one year of progress after one year of instruction, then their NCE scores would remain exactly the same and their NCE gain would be zero, even though their raw scores (that is, the number of questions they answered correctly) increased.

Some students will make more than a year’s progress in that time and will have a net gain in NCE score, which means that those students have learned more, or at least have made more progress in the areas tested than the general population.

Other students, while making progress in their skills, may progress more slowly than the general population and will show a net loss in their NCE ranks. As with many other scales related to the normal curve, the average NCE, by definition is 50.

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