Demographic data refers to information about the characteristics of a population, such as age, gender, race, education level, income, and geographic location. This data is often collected through surveys, censuses, and other forms of research to understand the composition and trends within a population. Demographic data is used by researchers to study patterns and disparities within different groups, to make informed decisions about policies and services, and to project future population trends. It is a key tool in social science research, market research, public health planning, and many other fields.