Cohort-survival population projection technique: A population projection technique which takes into account the age-sex distribution of the population as well as the influence of mortality, fertility, natality, and migration. An age-sex cohort is a group of individuals of the same sex within the same age range; e.g. 5-9 years old men. The population in each age-sex cohort is projected separately as each age-sex cohort is associated with different birth, death and migration rates. Female cohorts in the range 15-49 years old are also subject to different fertility rates within each age cohort. The projected populations in each cohort at the end of the projection period are added to obtain the total projected population of the study area.