Spurred in part by the apparent contradiction between recent data on the magnitude of autonomous female migration and the lack of acknowledgment of that data in recent literature, a 1979 study attempted to define women migrants in 46 Third World Countries in terms of age, marital status, socioeconomic status, factors motivating migration, and effects of migration. Because data from publications, national censuses, and studies frequently did not focus on autonomous female migrants, researchers constructed a sex differential migration index. While many regional differences existed in the areas studied (Africa, Asia, Central America, the Middle East, South America), female outmigration generally dominated only among migrants over age 50. Most female migrants were adolescent, in their early twenties, or over 50. Most were single and had less education than male migrants. A growing percentage migrated, often in step-wise fashion, for economic reasons. Having migrated to urban areas, many female migrants found themselves in low-paying, low status jobs. Researchers noted increased family responsibilities for female migrants and for rural wives of male migrants, and the weakening effect of serious economic dimensions of women's migration and on autonomous female migration. (SB)