The subculture of developmental disabilities services has embraced ideological perspectives from academia in general and from other service sectors, including, in recent years, the educational sector. Prevalent ideological and philosophical perspectives with growing in¯uence within the professional literature and to a lesser degree, the practitioner community, include postmodernist and constructionist doctrine. These perspectives in¯uence the depiction of utility of a wide variety of clinical and programmatic activities that typify services and, generally, impact upon decision making by policy makers, administrators, and possibly, to an important degree, by managers who in¯uence events at the point of clinical and service contact. This article discusses the nature and character of these in¯uences and the issues facing the ®eld, centering on the act of classifying a person with mild mental retardation, as well as uncertainties regarding both the process and consequences of classi®cation. Recommendations are made for an expanded but modi®ed role for adaptive behavior assessment in this process.