Demographic concepts and population indicators

A demography is the area of ​​knowledge that uses studies and information from Geography, Sociology, History and Anthropology to carry out studies of populations and their dynamics, which also involves the use of Statistic. Thus, demographic studies are concerned with general factors of the inhabitants of a given place, such as the structure age, growth prospects, migration, gender issues, mortality and many others factors.

For a better understanding of the behavior of populations, it is common to use some basic concepts. The main population concepts are population density, absolute population, overcrowding, growth rates and terms related to migrations.

FUNDAMENTAL DEMOGRAPHIC CONCEPTS

As for population numerical data, some basic terms are used, such as absolute population, which is the total number of inhabitants residing in a given territory, so that when this number is high, we say that it is an area

populous. On the other hand, if we consider proportional rates, we arrive at the concept of demographic density, which is the number of inhabitants for each unit of area, which is usually measured in square kilometers. When this density is high, we say that the place is densely populated and when it is low, we talk about demographic gaps.

The Brazilian territory, for example, has a population of approximately 204 million inhabitants in 2015 according to the IBGE, one of the largest in the world. On the other hand, as it is a country of continental dimensions, then the population density is only 24 inhab/km², which is considered a relatively low number. Therefore, it is common to say that Brazil is a populous but sparsely populated country.

In addition to these two concepts, there is also the overcrowding, which is used to designate those areas that suffer from a lack of resources or poor distribution of income, which makes that there is a large number of inhabitants below the poverty line or in very unfavorable social conditions. Therefore, a country may not be densely populated or populous, but still be overpopulated.

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When it comes to the increase in the number of inhabitants in a given area, there is a set of terms applied. The first concerns the number of children for each woman in terms of arithmetic mean, which we call fertility rate. already the birth rate represents the number of live births per thousand inhabitants, while the mortality rate represents, analogously, the number of deaths per thousand inhabitants.

In this sense, when we subtract the number of births from the number of deaths in a given period, we arrive at the concept of natural or vegetative growth, which represents the increase in the number of people in a given location without considering the entry and exit of inhabitants. In turn, the migratory balance represents the number of people arriving at the place of analysis (immigrants) reduced by the number of people leaving the place in question (emigrants). Consequently, the sum of vegetative growth and migratory balance gives us the general picture of the population growth of a region in a given period.

When at migrations, the main terms are linked to the duration of the displacement. The smallest of them is the commuting migration, which is the daily movement carried out by the inhabitants (such as going to work) being very carried out from one city to another in the so-called metropolitan regions. already the seasonal migration, occurs over a relatively longer period, but it is also a temporary movement, such as a trip for tourist or business purposes. Furthermore, there are permanent migrations, which may include cases of refuges (escape from a country), looking for a job or changing a professional relationship, among other possibilities.

A final type of migration worth mentioning is the type countryside-town, when there is a mass migration of the population from the countryside to the cities in a certain period of time, which is also called rural exodus. Unfortunately, this process culminates in urbanization or its intensification in different locations.

DEMOGRAPHIC AND SOCIOECONOMIC INDICATORS

Demographic indicators are used to assess the living conditions of populations in different parts of the world. in the world, in order to diagnose the main socioeconomic problems and establish goals and measures to fight them. Some of the most used indices are the HDI, the Gini Coefficient, the Unemployment Rate and the Poverty Line.

O HDI - Human Development Index – was prepared by the UN in the 1990s and seeks to measure the quality of life of populations. Thus, three main factors are taken into account:

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1. gross income per capita, which corresponds to the income of a given country divided by its population;
2. life expectancy, which is the average number of years people live in a location, which reflects health and safety conditions;
3. access to education, which is measured by the rates of literacy and the number of registrations made.

O Gini Coefficient – also called the Gini Index – is a mathematical data used to measure the social inequality. It analyzes the correlation between the poorest and richest populations, classifying them according to income levels. In numerical terms, this coefficient is measured from 0 to 1. The closer to zero, the more unequal the country; the closer to 1, the better the income distribution.

The data about the unemployment they are also fundamental to measure the development of a country and the quality of life of its population. In this case, the unemployment rate – also called vacancy rate – refers to the unemployed Economically Active Population (EAP), that is, the inhabitants who have the conditions and interest to work for pay but are unable to do so.

Finally, the poverty line or extreme poverty line is data created by the International Monetary Fund (IMF) and the World Bank in the 1990s to refer to the population living on a daily income of less than US$ 1.25 (one dollar and twenty-five cents). According to recent data, the number of people in these conditions reaches about 25% of the world's population, with most concentrated in underdeveloped countries.

By Rodolfo Alves Pena
Master in Geography