Demography refers to the systematic, statistical study and analysis of the population. It tries to understand the dynamics, trends, and processes of the population by focusing its attention on certain demographic processes such as birth, migration, aging, and death. These processes contribute to the population change and the trends that we find in the population such as the sex ratio, which is the number of females per 1000 males and other such trends.
Demography is derived out of two words, demos meaning people and graphic meaning to describe and thus is known as the study or description of the population. Further, it may be defined as either formal, which is concerned more with the quantification and measurement of the processes of the population and interpreting population size and growth, etc. Or it is social which refers to the field of demography, which is concerned with the economic, political and social aspects of the population. Demographic data is often collected in the form that is easily quantifiable, such as census or survey. Both are concerned with the systematic collection of data.
In India census was conducted for the first time between 1867-72 by the British Indian Government, after which regular census began to be conducted every ten years post 1881. In order to understand the demographic processes better, we must understand certain basic concepts which are often the focus of the study of demography as they help us understand better the changes in the population and its dynamics. A few such concepts are:
Birth rate: it refers to the total number of live births in a particular area at a given point of time per 1000 population.
Death rate: which is the number of deaths in a particular area at a given point in time per 1000 population.
Fertility rate/ total fertility rate: is the number of live births per 1000 women in the childbearing age group (15-49 years), if they are likely to be alive in this age group. Therefore it is a crude rate as it does not take into account the differences across the age groups.
From the total fertility rate arises what is known as the replacement level, which is the total fertility rate of 2.1 children per women.
However, we cannot overlook the fact that there are various instances of either infanticide or miscarriages leading to the importance of what is known as the infant mortality rate. Which is the number of deaths before the age of 1 per 1000 live births. Attached to this is the concept of the maternal mortality rate, it refers to the number of women who die at childbirth per 1000 live births.
Another important concept is the sex ratio, which, as mentioned above is the number of females per 1000 males, this helps us understand the composition of the population.
To understand and to be able to predict the population growth, we use the concept of growth rate, which is the difference between the birth and death rate.
Such demographic information helps in health planning, house planning, educational and employment planning, etc. and various other government policies, this is an important field of study to social sciences and especially sociology.