TO assess the influence of the organization and financing of health services on their utilization in general populations, it is desirable to choose contrasting regional or national systems. Before even this can be attempted, it is essential to estimate the extent to which a dependent variable such as utilization can be simultaneously and comparably measured in different communities. This feasibility study attempts to ascertain whether valid and comparable data bearing on the use of doctors' and nurses' services and on hospitalization among defined populations during a given time can be collected simultaneously in several settings with standardized procedures.This is . . .