Population Studies in Demography

What is Population?

Population studies is broadly defined as the scientific study of human populations. Major areas studied include broad population dynamics; fertility and family dynamics; health, aging, and mortality; and human capital and labor markets. researchers in population studies also focus on methodology. Population studies is an interdisciplinary area of study; scholars from demography, epidemiology, sociology, economics, anthropology, and various other disciplines study populations.

Population Studies in Demography

In biology, a population is all the organisms of the same group or species, which live in a particular geographical area, and have the capability of interbreeding. The area that is used to define a sexual population is defined as the area where inter-breeding is potentially possible between any pair within the area, and where the probability of interbreeding is greater than the probability of cross-breeding with individuals from other areas. Or , a community of animals, plants, or humans among whose members interbreeding occurs.

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In sociology, population refers to a collection of humans. Demography is a social science which entails the statistical study of human populations. Population in simpler terms is the number of people in a city or town, region, country or world; population is usually determined by a process called census (a process of collecting, analyzing, compiling and publishing data)

A research population is generally a large collection of individuals or objects that is the main focus of a scientific query. It is for the benefit of the population that researches are done.


In anthropology also, the concept of population as a reproductive community is essential for analysing human biological variability and explaining the way it emerges in time and space. For this reason, anthropology emphasises the changing processes operating in human populations, closely linked to social life and culture. Indeed, anthropology, beyond its technical devices is, above all, a way of thinking. It is the history of population which becomes the guiding axis for its research. 

In general ecology, the several populations in an area are considered together as a complex rather than singly; they represent different species, animal and plant, which depend on each other, sharing the same environment, together forming a living community: a biocenosis (Olivier, 1975).

Even in the case of palaeo-anthropology, despite the lack of adequate sampling to meet strict statistical requirements, where scarce fossil remains, sometimes unique, provide the only information on one or more members of the populations, it is possible to analyse and interpret the data in a probabilistic way. In these analyses, the palaeo-environmental context is considered in the wide sense, including the physical as well as the cultural environment.

In statistics, a population is a set of similar items or events which is of interest for some question or experiment. A statistical population can be a group of actually existing objects (e.g. the set of all stars within the Milky Way galaxy) or a hypothetical and potentially infinite group of objects conceived as a generalization from experience (e.g. the set of all possible hands in a game of poker). A common aim of statistical analysis is to produce information about some chosen population.


In statistical inference, a subset of the population (a statistical sample) is chosen to represent the population in a statistical analysis. If a sample is chosen properly, characteristics of the entire population that the sample is drawn from can be estimated from corresponding characteristics of the sample.

On the other hand, from the demographic point of view a population is more constricted, since it is defined by pre-established limits, often administrative or political, in a conventional way: e.g. an urban population, student population, or the population of a province or a country. These are quite different uses of the term "population" from that in studies of the genetics of human populations where, as noted above, it is a community or communities made up by individuals who reproduce sexually or who are potentially capable of doing so. It is a group in which each member has the same probability of mating with other members of the opposite sex (Strickberger, 1976). From this point of view, what are the limits of a population? Usually, they are undefined, since in general, there are no clear borders among the genetic communities. Individuals separated by large geographical distances or physical barriers, or who do not speak the same language, have less chance of forming a couple, even though this would be biologically possible. Closed populations, genetically isolated from the others, are rather an exception.


Science/Definition of Population

Populations can change through three processes: fertility, mortality, and migration. Fertility involves the number of children that women have and is to be contrasted with fecundity (a woman's childbearing potential). Mortality is the study of the causes, consequences, and measurement of processes affecting death to members of the population. Demographers most commonly study mortality using the Life Table, a statistical device which provides information about the mortality conditions (most notably the life expectancy) in the population. 

Migration refers to the movement of persons from a locality of origin to a destination place across some pre-defined, political boundary. Migration researchers do not designate movements 'migrations' unless they are somewhat permanent. Thus demographers do not consider tourists and travelers to be migrating. While demographers who study migration typically do so through census data on place of residence, indirect sources of data including tax forms and labour force surveys are also important. 


Demography is today widely taught in many universities across the world, attracting students with initial training in social sciences, statistics or health studies. Being at the crossroads of several disciplines such as sociology, economics, epidemiology, geography, anthropology and history, demography offers tools to approach a large range of population issues by combining a more technical quantitative approach that represents the core of the discipline with many other methods borrowed from social or other sciences. Demographic research is conducted in universities, in research institutes as well as in statistical departments and in several international agencies. Population institutions are part of the Cicred (International Committee for Coordination of Demographic Research) network while most individual scientists engaged in demographic research are members of the International Union for the Scientific Study of Population, or a national association such as the Population Association of America in the United States, or affiliates of the Federation of Canadian Demographers in Canada. 


According to Social Work Dictionary, “The total number of people in a nation or other specified geographic region; also, the number of people of a specified class or group (such as women, Roman Catholics, black people and disabled people) is a specified place or geographical region.”

According to Dictionary of Sociology by P. Scott, “The term population studies refer to the study of the inter-relationship between population composition and distribution and wide variety of social and economic variables.”

According to Merriam-Webster, Population refers to the body of persons or individuals having a quality or characteristic in common; the organisms inhabiting a particular locality; a group of interbreeding organisms that represents the level of organization at which speciation begins.

According to Genetics: Principles and Problems by Daniel L. HartL, (2007-45) “A Population is all the organisms that both belong to the same species and live in the same species and live in the same geographical area.”

According to ‘The study of population’ (1959-02) by Philip M. Hauser and Otis Dudley Duncan, “Demography analysis is confined to a study of the components of population variation and change. Population studies are concerned not only with population variables but also with the relationships between population changes and other variables social, economic, political, genetic, geographical and the like.”


Characteristics of Population

It indicates human population

It is an assemblage of human beings

It’s one of the core parts of demography

It indicates the inhabitants of a specific geographical area

It can be continually modified or changed by different variables (natural and social environment, birth-death, migration, intellectual situation, state policy etc.)

It’s varied by situation, time , duration and environment


Common rates and ratios of Population studies / Demography

The crude birth rate, the annual number of live births per 1,000 people.

The general fertility rate, the annual number of live births per 1,000 women of childbearing age (often taken to be from 15 to 49 years old, but sometimes from 15 to 44).

The age-specific fertility rates, the annual number of live births per 1,000 women in particular age groups (usually age 15-19, 20-24 etc.)

The crude death rate, the annual number of deaths per 1,000 people.

The infant mortality rate, the annual number of deaths of children less than 1 year old per 1,000 live births.

The expectation of life (or life expectancy), the number of years which an individual at a given age could expect to live at present mortality levels.

The total fertility rate, the number of live births per woman completing her reproductive life, if her childbearing at each age reflected current age-specific fertility rates.

The replacement level fertility, the average number of children women must have in order to replace the population for the next generation. For example, the replacement level fertility in the US is 2.11. 

The gross reproduction rate, the number of daughters who would be born to a woman completing her reproductive life at current age-specific fertility rates.

The net reproduction ratio is the expected number of daughters, per newborn prospective mother, who may or may not survive to and through the ages of childbearing.

A stable population, one that has had constant crude birth and death rates for such a long period of time that the percentage of people in every age class remains constant, or equivalently, the population pyramid has an unchanging structure. 

A stationary population, one that is both stable and unchanging in size (the difference between crude birth rate and crude death rate is zero). 

A stable population does not necessarily remain fixed in size. It can be expanding or shrinking. 

Note that the crude death rate as defined above and applied to a whole population can give a misleading impression. For example, the number of deaths per 1,000 people can be higher for developed nations than in less-developed countries, despite standards of health being better in developed countries. This is because developed countries have proportionally more older people, who are more likely to die in a given year, so that the overall mortality rate can be higher even if the mortality rate at any given age is lower. A more complete picture of mortality is given by a life table which summarizes mortality separately at each age. A life table is necessary to give a good estimate of life expectancy.

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