How to Understand and Use NCE’s and Stanines

ByLavinia E. Smith

May 25, 2023

Some scores on an achievement test are less meaningful than others to parent educators and classroom teachers. The normal curve equivalent, commonly referred to as the NCE score, falls into this category.

If a score lacks meaning, it often lacks usefulness and is considered irrelevant as well. Nevertheless, because NCE’s are part of most achievement test reports, here are two things you should know about this score.

First, NCE’s are similar to percentile ranks in as much as they rank your student’s score from 1 (low) to 99 (high). If you look at the sample report on our website, you will see that the NCE scores follow the NP scores as you look across the report from left to right. The NCE score for the Total Score on our sample report is 50. Achieving an NCE of 50 is the only time the percentile score and this score are the same. When percentile rank scores are higher than 50, NCE scores will always be lower. The NCE score for Language on the sample report illustrates this. When percentile ranks are lower than 50, NCE scores will be higher. The NCE scores for Reading and Math on the sample report illustrate this.

Secondly, NCE scores allow for “meaningful” (meaningful to statisticians primarily) comparisons between different achievement test batteries and between different tests within the same battery. How this works is complicated, and I won’t go into it here.

In the column to the right of the NCE scores are the Stanine scores. The name of this score comes from the fact that it ranks student performance on a standard scale of 1 (low) to 9 (high). A stanine score of 5 falls in the middle of this scale and in our sample report corresponds to a percentile rank of 50, indicating that a student’s performance falls in the average range. Likewise, a stanine score of 4 links to a slightly below average percentile rank as we see for Reading subtest. A stanine score of 6 links to a slightly above average percentile rank as we see for Language subtest.

The stanine’s value comes from the fact that because it is expressed as a single digit number, it’s easy to draw quick conclusions about a student’s performance. Stanine’s of 1’s or 2’s suggest a student had trouble with the content on the test. Stanine’s of 8’s or 9’s suggest a high degree of mastery of the concepts covered. Keep in mind, though, that stanines are less precise than percentile ranks.

Curt Bumcrot, MRE

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