This national study explored the effects of teachers and their working conditions on the caliber of center-based child care in the United States. Study goals were to: (1) compare center-based child care services in 1988 with those of 1977; (2) examine relations among child care staff characteristics, adult work environments, and quality of child care; and (3) investigate differences in child care quality, child care staff, and adult work environments in centers that varied with respect to standards, accreditation status, auspices, and families served. Participants were 227 centers in five metropolitan areas: Atlanta (Georgia), Boston (Massachusetts), Detroit (Michigan), Phoenix (Arizona), and Seattle (Washington). Classroom observations and interviews with center directors and staff provided data on center characteristics, program quality, and staff qualifications, commitment, and compensation. In addition, child assessments were conducted in Atlanta in an effort to examine effects of varying program and staff attributes on children. Results are reported and recommendations offered. It is concluded that the study raises serious concerns about the quality of services many American children receive. Findings also indicate how services can be improved if the necessary resources are devoted to accomplishing this. (RH)