DEMOGRAPHY IS THE study of populations (a term used to denote the collection of persons alive at a particular point in time and who meet certain criteria). Demographics have to do with population statistics. Usually referred to as a census, most often these data are collected through a survey process and by public agencies at all levels of government or non-governmental organizations. These data include variables representing vital economic and social statistics. They generally include race, age, gender, religious affiliation, educational levels, income levels, and housing and employment information. They also include information about population density, which is the number of people per square mile, as well as how the total population and population subgroups are distributed throughout a selected geographical area. The information collected by agencies may include data on death and birth rates, life expectancy, and health problems, to name a few. When linked to basic demographic data, researchers can better understand links between these variables; for instance: the life expectancy of American males who are of Hispanic ethnicity and have yearly incomes below $18,000.

Most countries have a formal census process that attempts to count every member of the population and to collect information about that person and his or her household. All of this individual data is then aggregated (combined) and sorted by variables to inform us about the people in a particular area. For most of Europe, census taking dates back to the 16th century. The founding fathers of the UNITED STATES recognized the value of collecting population data and ensured that the process would be funded and protected by the U.S. Constitution.


The U.S. Census Bureau conducts a census every 10 years. In addition to taking a “head count,” each individual is asked to identify sex, age, relationship status, race, whether or not of Hispanic origin, and housing tenure and ownership status. Approximately 15 percent of the population is selected randomly to receive a longer survey from which additional demographic information is collected. These additional demographic data include marital status, place of birth, citizenship and year of entry, ancestry, place of residence five years ago, language spoken at home, veteran status, disability information, present labor force status including industry, occupation, and class, place of work and journey to work, previous year's work status, and previous year's income. Housing data, which are socioeconomic indicators, are also collected. Statisticians also use equations to make assumptions about the U.S. population at different levels of geography (local, state, country) and cross-reference socioeconomic data with demographic data to create population profiles. The smallest census geography is a “block.” It represents approximately 150 people and gives a very detailed picture of the people who comprise a small area while protecting each individual's right to privacy.

Developing countries also recognize the need for population counts and surveys but are often impeded by resources, political strife, and massive shifts in population resulting from civil war, famine, etc. These countries are aided by organizations like the United Nations in collecting important demographic data to aid economic development and stability through resource management.

The process of collecting demographic data is becoming more complex as the world's population increases and many countries, such as the United States, become more heterogeneous and mobile. As a result, understanding demographics has also become more complicated because many individuals no longer fit neatly into one particular race or ethnicity category. Further complicating the process in all countries is the fact that many census takers and demographic researchers are challenged by accuracy problems resulting from community and individual reluctance to report personal information.

Demographic data provides students, researchers, and decision makers with information that is essential to understanding our world. It allows us to identify social groups, shifts in populations through migration and immigration, relationships between people and geography (cities, states, countries, world regions, and the world as a whole), as well as relationships between people, political boundaries, and resources. Demographics have a wide scope of applications. For example, private industries might use census data and market research for product development, targeted advertisement of services and products, and selecting new markets/locations for business development.

Demographics also play a vital role in how government dollars are allocated. Some of these decisions are linked to total population numbers, while others are linked to particular demographics such as age, race, gender, income, or a combination of these. Additionally, nonprofit organizations might use demographic data to improve service delivery by targeting geographic areas with assumed specific needs based upon the area's demographic profile.

Demographic data not only provide information about today, they also help us establish population trends that can help predict and prepare for the future. Newer demographic changes make it difficult to measure and understand the sources for that change until more data is collected over time. An example: in 2000, the U.S. Census Bureau began collecting information about grandparents serving as caregivers; the true scope of this demographic shift will not be measurable until the same data is collected again in 2010. Likewise, some changes have been gradually occurring over a longer periods of time and substantial data have been accumulated for examination. These data and changes allow researchers to use statistical modeling to project future population trends and make recommendations for preparation and response. By doing so, decisionmakers such as politicians and organizational leaders have information to guide them in allocating resources to plan for future need and demand on resources.

Population growth tends to be very imbalanced between rich developed countries and poorer developing and third world countries. Countries in Asia and Africa have large population numbers of people under the age of 15, whereas countries in North America and Europe have fewer young people and rapidly aging populations. These basic statistics indicate very different demographic futures as well as different demands on resources. A younger population will require more schools and job training, whereas an older population will require increased geriatric programs and services to respond to long-term health problems that result from aging. Governments and agencies can use this information to plan for these needs. Private sector businesses can also use these projections for business development.

Population change at all geographical levels will eventually affect economic consumption, social and political relationships, and environmental outcomes to name just a few of the impacts. Without demographics, many decisions about natural and monetary resources would be random, and it would be difficult to project long-term impacts to allow better use of the world's and countries' limited resources.


Demographics are inextricably linked to geography. As a result of the internet, we can easily access data about the world's population as a whole or by region, a country's population, a state's population, or a city's population. Sophisticated mapping software, such as geographic information systems (GIS), provides the technology to link demographic data to their respective locations. By examining demographics and linking them to place, we learn a lot about the available labor force, the need for age-appropriate services (such as day care or day programs for the elderly), and we can make assumptions about quality-of-life issues. For example, an area populated with people with moderate incomes and college educations will likely have better quality of life, through access to resources, than areas with high poverty and low education rates. Many demographic data have been mapped and made available to the public. These maps allow us to see patterns that may not be obvious when looking at numbers.