How is a Raw Score of 0 on a Test Equal to a Low Average/Average Score?

Overview

In some cases, a raw score of 0 may produce a Low Average or even Average standard score for very young examinees. While this may seem unusual, it is a result of the statistical process used to develop the test norms and does not necessarily indicate average or above-average ability.

Why This Happens

At very young ages, there is often very little variability in the norming sample. Many children in the same age group may answer only 0, 1, or 2 items correctly on certain tests. Because the scores are clustered so closely together, the distribution has very little spread (variance).

This low variability results in relatively small standard deviation values for that age group. As a result, a raw score of 0 may convert to a higher-than-expected norm-derived score, such as a standard score in the Low Average or even Average range.

Factors That Affect the Score

The relationship between a raw score and a norm-derived score depends on:

• The specific test that was administered.
• The examinee's age or grade level.
• The characteristics of the normative sample for that test and age group.

Because of these factors, the same raw score may convert to different standard scores across different tests or age groups.

Summary

An examinee may receive a raw score of 0 yet still obtain a standard score that appears to be in the Low Average or Average range. This does not mean the examinee demonstrated average ability. Instead, the score reflects the statistical characteristics of the normative sample for that age group.

When interpreting these results, examiners should recognize that an inflated norm-derived score in this situation is a statistical artifact of the norming process and should not be interpreted as evidence of average or above-average performance.