The ECLS-B Direct Assessment: Choosing the Appropriate Score for Analysis

The Bayley Short Form – Research Edition (BSF-R). At the base year (henceforth called the 9-month wave, as children were approximately 9 months of age at the time of assessment) and first follow-up (henceforth called the 2-year wave, since children were approximately 2 years of age at the time of assessment), the Bayley Short Form-Research Edition (BSF-R) was used. The BSF-R consists of a subset of items from the Bayley Scales of Infant Development, 2nd Edition (BSID-II). Item Response Theory (IRT) modeling was used to select items from the BSID-II for the BSF-R. The items included on the BSF-R represent all of the constructs covered by the BSID-II, are easy to administer, require few materials, and are straightforward to score. Study children were administered these items (i.e., the BSF-R) in place of the longer BSID-II.