Nonstandard standard scores on the Vineland Adaptive Behavior Scales: a cautionary note.

The means and standard deviations of standard scores on the new Vineland vary considerably from age group to age group in the standardization sample. As a consequence, different standard scores may reflect the same level of performance in terms of distance from the mean, and conversely, the same standard score may reflect different levels of performance. The problem is particularly significant for the assessment of mentally retarded individuals.