This report concerns the field procedures and data analysis being used in the New York City Infant Day Care Study, a large-scale longitudinal study examining publicly-funded, community-controlled group and family day care programs in New York and comparing the effects of these programs and of home rearing on children and their families. Children's development and the patterns of care provided to them in group and family day care, as well as at home, are being evaluated and compared in three major areas: (1) child's health, nutrition, and physical development; (2) child's cognitive, linguistic, social, emotion, and personality development; and (3) family development. Procedures for assessing program input and developmental outcomes in these areas are described and design of the data analysis is discussed. The appendices, comprising most of the report, include (1) identification of committee members, (2) forms and manuals for the field procedures (three fourths of the report), and (3) material relevant to the data analysis procedures and analytical framework. (Authors/ED)