Monday, April 13, 2015

Demography 1.1: Definitions

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Definition: The origin of the word “Demography” (demos =people, graphin = to write) suggests the general nature and scope of the subject matter. That is, demography is concerned with the description, analysis and understanding of the population phenomena.
According to Frank Lorimer, “In broad sense, demography includes both demographic analysis and population studies. A broad study of demography studies both qualitative and quantitative aspects of population.”
According to Peter R Cox, “Demography is the study of statistical methods of population involving primarily the measurement, size, growth of the people, the proportions of leaving being born or dying within the same area or region and related functions of-
- Fertility
- Mortality
- Marriage”
According to Donald J Bogue, “Demography is the mathematical and statistical study of the size, composition and spatial distributions of human population and of changes over time in these aspects through the operations of five processes-
-Migration and
-Social Mobility
Demography and Economics:
Economics studies economic problems of the people and in these demographic and population studies play a vital role.
When there is more population, economic activities are bound to increase. Population problems are directly linked and concerned with
-Per Capita Income
-Industrialization etc
Demography influences economics in two important and different ways. On one hand, it as a means of labor force, becomes source of production. On the other hand, changes in the population influences labor force and the source of production.
Some Basic Concepts of Demography:
1. Live Birth: Live birth is the complete expulsion or extraction from its mother. Live birth is the beginning of life and influences population. Live birth is very important both in growth of population & social life.
2. Still Birth: When one thinks of birth in demography one includes in it both live birth & still birth. Live birth is of course somewhat simpler in counting because in it are counted all those children who did not come out of the womb of the mother but the woman remained pregnant for 28 weeks.
3. Family Size: Though commonly from family size, we mean total number of persons of a family, yet in demography it does not mean so. In demography, it means number of children a woman or couple has at a point of time. The complete family size indicates the total number of children born by a woman up to the end of her reproductive period.
4. Child Death: Usually due to social or other causes there are many deaths in many countries within a period of one year of the birth of the child. In some cases, whereas newly born baby dies, in some both the baby as well as mother dies. This increases death rates as well.
Deaths which occur within a period of 4 months from the birth of a child are known as Neonatal period of deaths. The deaths which takes place between a period of 4-12 months are known as Post Neonatal Period of deaths.
5. Sterility: A man or woman or couple who has not given birth to child is called sterile. It is used both in connection with individuals or groups consisting either men or women or both. But usually sterility measures are computed only for women.
6. Parity: In demography women are classified according to the number of children born alive to them. As for example, first parity women are those who have given birth to one child, second parity women are those who have given birth to two children & so on.
7. Adulthood: Adulthood means that it is at this stage that boy or girl becomes capable to produce children.
8. Reproductive span: It indicates child bearing period of a woman. Only women can conceive & give birth to children & that too within a limited period & certain age limits.
9. Fecundity: Fecundity is that stage in a life of girl by which she becomes capable of becoming mother, no matter whether she actually becomes or not. If she is capable of giving birth to a child she is called fecund.
10. Fertility: Fertility is tha standard of measuring the capacity of the women to produce children. According to Thomson & Lewis, “the born fertility is generally used to indicate the actual reproductive performance of a women or a group of women. The crude birth rate is only one measure of fertility.
Thus it is obvious that a fecund woman may not be fertile but a fertile woman must be fecund because if she is not then fertility has no meaning.
11. Cohort: In demography the children who are born in one year are called cohort.
12. Relative Number: Relative numbers are needed only when comparison is desirable. Both the ratios & rates are relative figures & expresses a relation between two or more numbers.
13. Ratio: Ratio expresses the size of one to another. As for example male female ratio in a country or a region etc.
14. Rates: Like another ratios, a rate is also computed & that help in expressing what has happened in terms of a certain unit of time. Two most commonly used rates in Demographic studies are Birth & Death Rates.
15. Birth Rates: The procedure for calculating birth rate is by finding out total number of births in a given area during a given year and by dividing that by total number of people living in an area at the mid-point of that year and multiplying that by 1000.
16. Death Rate: Death rate is also computed by the similar way as the birth rate.
17. Crude Rate: Both birth rate & death rate are however called CRUDE Rate. Because, these (birth rate & death rate) use total population as a base number rather than parts of the population.
Usually midyear population is used because it is probably the figure which is both nearest to the average population for the year a readily obtainable.
Methods & Sources of Data Collection: A census of population may be defined as “ total process of collecting, compiling & publishing demographic, economic & social data pertaining at a specific time or times to all persons in a country or delimited territory. According to V M Dandakar, “ A census of population is the total process of collecting, compiling, evaluating, analyzing & publishing demographic, economic & social data pertaining at a specific time to all persons or in a delimited part of the country.
There are two important census techniques:
1. De Facto Method &
2. De Jure Method
Note: A De Jure count of the total population is the enumeration of persons who usually reside in a given place. A De Facto count is the enumeration of persons physically present at specified place on census night.
1. De Facto Method: It is one of the census techniques. Under this system, a date is fixed for taking census of the whole country. Usually such an operation is conducted at night because it is felt that after day long work people will come back to their homes at night. Such a night is called census night. This night is very carefully selected.
At this night all those who are found anywhere are counted. When the people actually present are counted at the same moment in a census technically that is called De Facto Population.
Since the census is completed on a particular date, it is also called Date System or One Night Enumeration System.
Merits of De Facto Method: This method is quiet simple as well as clear.
1. Under this system floating population is not counted & the data becomes inaccurate.
2. This system needs a large number of well qualified & trained field workers.
3. Night time is the rest time & enumerator/invigilator is not welcomed at home.
2. De Jure Method: Under this, every person in an area is personally counted & information obtained from him/her. Temporary resident is not included in it. Whoever is enumerated, his/her permanent place of residence is considered. Usually census work is completed within 2 or 3 weeks.
Merits of De Jure Method:
1. Since period is 2/3 weeks so chances of inaccuracy is little bit short.
2. Many question regarding gender, age, social conditions can be asked.
1. Under this system permanent residence, household etc are to be defamed. It is difficult to define uniformly.
2. It becomes difficult to collect information in respect of those who have no permanent residence.

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