Normal curve equivalent scores (NCE scores) are one type of normalized standard, norm-referenced scores. Norm-referenced scores report the results of standardized assessments and other instruments in a way that permits the comparison of an individual’s performance with a very well-defined norm group of similar individuals who have completed the same assessment. Publishers of norm-referenced assessments will typically transform scores so that they can be placed along a common distribution. This common distribution is called a normal distribution, normal curve, or bell-shaped curve.

There are numerous types of scores that are transformed for ease of interpretation in relation to a norm group. These include linear standardized scores (e.g., Z scores and T scores), which report how far a raw score is located from the mean score of ...