Review of the Bayley Scales of Infant Development—Second edition

Abstract

The Bayley Scales of Infant Development-II (BSID-II) is a long-awaited revision/ restandardization of a widely used instrument. This version retains Mental and Motor scales from the original with a complete revision of the Behavior Rating scale. The goals for the revision of updating materials, expanding content coverage, extending the age range, improving clinical utility, updating the norms, and improving reliability and validity have been met for the most part. Specific recommendations are offered for improvement of test materials. Reservations about the use of the test with clinical populations and about interpretations of facet scores are expressed. The new Bayley looks as though it will provide an excellent tool for assessing youngsters aged 1–42 months. However, more research is indicated before clinicians can be as confident in their results as they were with those from its predecessor.