Population trends refer to the changes in the size, composition, and distribution of human populations over time. This research area analyzes various factors that influence population growth or decline, such as fertility rates, mortality rates, migration patterns, and age distribution. Researchers in this field study how population trends impact social, economic, and environmental dynamics, as well as public policy and planning decisions. The goal is to understand and forecast population changes in order to address challenges related to healthcare, education, housing, and resource management.