Potential scoring problems using the Bayley Scales of Infant Development-II Mental Scale

When testing children with developmental delays on the BSID-II Mental Scale, the examiner has the option of starting at the child's chronological age (CA) or at the child's estimated level of functioning. Different starting points can yield different scores. The higher the starting point, the higher the score. When scores on the BSID-II administered in its entirety and scores predicted from the original BSID concurrently administered to 32 children with developmental delay were used as criteria, starting at the child's CA inflated BSID-II scores. Results were skewed in the opposite direction when testing started at the lowest item set. Testing downward until the child passed all items and upward until the child failed all items eliminated the problem of false basais and ceilings and yielded scores consistent with those predicted.