It comprises of bars, drawn horizontally with the length of each bar indicating the number of persons in each age-group in a population.
The population is usually divided into 5- year age groups (0-4, 5-9, 10-14, 15-19………..).
The youngest age group is always shown at the base of the graph.
The shape of the age-sex pyramid provides valuable insights into the population structure and dynamics. The pyramid can take various forms, including expansive, constrictive, or stationary shapes, each indicating different patterns of birth rates, mortality rates, and population growth. Here are some common patterns:
- Expansive pyramid: This pyramid shape has a broad base and tapers towards the top. It indicates a population with a high proportion of young individuals and suggests high birth rates and rapid population growth. This shape is often associated with developing countries or regions with high fertility rates and limited access to family planning.
- Constrictive pyramid: A constrictive pyramid has a narrower base and wider top. It suggests a population with a lower proportion of younger individuals and a higher proportion of older individuals. This shape is commonly associated with developed countries or regions with lower birth rates, lower fertility rates, and longer life expectancy.
- Stationary pyramid: A stationary pyramid has relatively equal proportions across age groups, resulting in a rectangular or near-vertical shape. This shape indicates a population with a relatively stable age distribution, where birth rates and death rates are roughly balanced. It is often associated with countries or regions that have achieved demographic stability with low fertility and mortality rates.
Analyzing the age-sex pyramid helps to identify important demographic trends, such as population growth, age dependency, potential challenges related to aging populations, and the implications for social and economic development. The pyramid can assist policymakers, researchers, and planners in understanding the needs of different age groups and formulating appropriate policies and programs related to healthcare, education, employment, and social welfare.