How the Use of Age-Cluster Norms Can Reveal Otherwise Hidden Findings.

This study was designed to determine the amount of information obtainable when age-cluster norms (whereby student norms are available for 2- to 3-month age-group norms) are used instead of the usual grade-level norm grouping procedures. This distinction is particularly significant for studies of young children. Data included pre- and post-test scores on the Missouri Kindergarten Inventory of Developmental Skills for 12,917 Hawaiian kindergarten students and on the Peabody Picture Vocabulary Test (Revised) for 6,838 students. The two tests are used as part of the Early Provisions for School Success--a statewide kindergarten program. A parallel secondary analysis was conducted for students of limited English proficiency. For the language tests, the use of age-group norms, as opposed to sole use of cohort norms, resulted in more precise information. On the other subtests, there seems to be less need to be concerned about age-group cluster norms. Eight data tables are included. (TJH)