According to demographics, the world population exceeds 8 billion people.
Demography is the analysis of human communities based on statistics . The concept comes from a compound Greek word that can be translated as "description of the people" . This discipline studies the size, stratification and development of a community from a quantitative perspective .
In demography, the population is a group of people linked by reproductive ties that can be identified by cultural, social, geographic, political or other characteristics. The population, therefore, has continuity over time, although it is not eternal.
From this definition, we can understand that demography is the social science that is responsible for analyzing the processes that determine the creation, maintenance and eventual disappearance of populations. Concepts such as fertility , migration (both emigration and immigration ) and mortality are key to demography, since they determine the structure of each population.
Origin of demography
The Arab statesman and sociologist Ibn Khaldun ( 1332 – 1406 ) is considered a pioneer in the field of demography. He was the one who began collecting statistical information to study populations and generate new data from these statistics.
The British John Graunt ( 1620 – 1674 ) and Thomas Malthus ( 1766 – 1834 ) also made great contributions to the development of demography.
Birth and death rates and migration movements
The birth rate , the mortality rate and population movements are part of the basic studies of demography, whose work is very important for the development of State policies .
For example, demographic data can help us understand the main public health problems or which regions of a country are economically disadvantaged.
Let's take the case of migration balance . If more people emigrate from a community than arrive through immigration , population density is likely to decline, although other factors must be considered.
Demographics also provides valuable data on geographic distribution, capable of revealing overpopulation or underpopulation in certain regions.
Demographic studies help to understand the family structure of households.
Types of demographics
Within this social science there are various branches. Among them there are the following: general demography (investigates the theories that exist around demography and the research methodologies used); geographic demography (checks the mobility of populations: migrations, new settlements, etc.); historical demography (studies issues related to fertility, the mortality rate and migrations that occur within a group); study of fertility (which is responsible for analyzing birth and marriage rates and the fertility rate of the population); and study of mortality (analyzes the mortality rate of a group in general and the causes and age of deaths in particular, determining life expectancy and trying to relate the various variables).
In order to carry out demographic studies , various censuses are carried out with the aim of extracting relevant information about the state of the population being studied: the number of occupied homes, the number of people living in each one, their illnesses, deaths that have occurred in the last year in each family, migrations , etc.
The results of these analyses not only allow us to know the current size of the population, but also the risks to which they are exposed , and can help to find solutions or prevent lethal consequences such as plagues, famines or accidents.
Demography allows us to analyse infant mortality and take measures to prevent it.
The population pyramid
Demography allows for the creation of a population pyramid . This graph shows, through bars, the number of individuals by sex and age.
This representation thus helps to visualise demographic growth by age group. It also helps to infer information about the economically active and inactive population, it is used to examine the ageing rate and it makes it possible to know the distribution by sex, among other variables.
Methods of studying demographics
There are two main types of study methods within this social science:
- Composite method : This involves combining different study techniques that allow us to arrive at an approximate conclusion about the conditions of the population studied. One of these techniques could be, for example, observing school enrolment . Researchers can have a rough idea of the changes that the population has undergone from one year to the next in the sector of the group that is of school age; in this way, they could find out the number of minors there are and check the migrations that the population has undergone in the last year of young people of school age.
- Statistical methods : These are the most accurate because they are carried out by obtaining specific data collected from censuses. Through statistical theories, the changes indicated in the census results can be related and information can be obtained about the conditions in which the population is found at the time of carrying out said analysis.