Introduction The utilization of health services is understood to be related to a number of individual and family characteristics, such as age, proximity to urban centers, and economic level, among others. Economic level is perhaps especially important in societies where the private sector of health looms large and ability to pay is crucial to the utilization of services. Under any circumstances, however, socioeconomic level is likely to be of concern as an indirect reflection of the level of knowledge, attitudes, and expectations regarding health services. The economic factor takes on added relevance for planning purposes in nations experiencing rapid economic growth, for then services for the future must envisage more than added numbers in the population, taking cognizance of the greater per capita utilization of health services as well. Important as the economic factor is as an independent variable in health planning, it is less clearly and unambiguously defined than the other factors noted above. The distinction between children and adults is quite apparent, but that between "poor" and "moderately well off" is neither obvious in principle nor accurately elicited from respondents in practice.