A multifactor instrument, the Bentler Interview Developmental Scale (BIDS), was used to measure developmental changes in children from birth to age 7. The device consisted of 115 age related items to which the mother responded. Data was gathered through interviews of the mothers of sample children throughout the United States. Reliability of the instrument was .83 for girls and .81 for boys. The internal consistency coefficient, based upon 4754 interviews of girls and boys, was found to be .90 and .89 respectively. The BIDS instruction booklet, both girls' and boys' versions of the instrument, reliability tables, growth data, preliminary norms, and summaries of 12 validity studies are included in appended tables. (CK)