Offers standard errors of prediction and confidence intervals for Vineland Adaptive Behavior Scales (VABS) that help in deciding whether variation in obtained scores of scale administered to the same person more than once is a result of measurement error or whether it reflects actual change in examinee's functional level. Presented values were…

The importance of using the standard error of measurement (SEm) in determining reliability in test scores is emphasized. The SEm is compared to the hypothetical true score for standardized tests, and procedures for calculation of the SEm are explained. (JDD)

This paper discusses standard error of measurement (SEM), the amount of variation or spread in the measurement errors for a test, and gives information needed to interpret test scores using SEMs. SEMs at various score levels should be used in calculating score bands rather than a single SEM value. (SLD)