This paper investigates the evidence for adult-infant ratios in day care centers, finding that current evidence is based largely on the premise that a low number of infants per adult should result in greater interaction between the adults and the infants, and, thereby, better infant care. Support for this premise is derived from three main sources: (1) research conducted on animals and institutionalized infants; (2) research which shows that small numbers of children per adult can result in increased IQ's and cognitive functions; and (3) statistical reports which show high infant mortality rate, particularly among children of low social status parents. It is concluded that the polemics over staff-infant ratios in day care centers can only be resolved by scientific research into day care center conditions, and surveys of staff and parents of children served in the centers under consideration. Quality day care, rather than ratios, is the issue to be emphasized. Also discussed are a number of points of departure for determining quality day care and characteristics of good early childhood programs. (Author/MS)