A standard based on measurement of a large group of persons, used for comparing the scores of a person with those of others in a defined group.
Numerical or statistical measure(s) of usual observed performance. For example, a norm for care of appendicitis would be the usual percentage of appendices removed in cases diagnosed as appendicitis which are shown by pathology to be diseased. A norm can be used as a standard but does not necessarily serve as one. Both norm and standard imply single, proper values lather than a range.
In testing, usually the average scores of groups of people who have taken a particular standardized test, used as a basis of comparison for those taking the test later. A child’s test score is compared with the norm, and the comparison is sometimes expressed as a grade-equivalent score or age-equivalent score. Most widely used, numerically scored tests are developed and standardized on large populations, and the scores tend to be distributed evenly along a normal distribution or bell curve, like an upturned tulip-shaped bowl, with most scores falling in the middle and many fewer scores at the top and bottom ranges. Norms may also, more generally, refer to social expectations about behavior and to the “average” behavior seen in a group. Some kinds of tests, such as the Gesell Preschool Test, use the term norm more in this sense, as a behavior observed in more than half of the children of a particular age group. Confusion results when many who use the test wrongly treat the Gesell norms as if they were standardized norms with a strong statistical basis.
The expected value for something measurable. Most people have measurements lying to either side of the norm. Traditionally in medicine, only those lying beyond two standard deviations from the norm are considered likely to be abnormal (approximately 3 per cent of those measured).