Page 28 - University English for non-speacalist

Demography
The field of social science that concerns itself with the study of population characteristics
and trends is termed Demography. Demography have developed concepts, analytical tools,
paradigms, and theories to examine the size. Distribution, and age-sex structure of populations
and to understand and explain any temporal, inter or intra societal variations that exist.
Demography is invaluable, therefore, to planners and decision-makers in society because it
enables them to formulate and implement policies and projects on a scientific basis and to avoid
the pitfalls of relying on guesswork and trial and error. Doubling time, total fertility ratios, life
expectancy, infant mortality, and immigration and emigration rated are all examples of the
indicators that demographers have developed to study and analyze population trends.

Doubling time is an estimate of how many years it will take for the number of people
living in a given geographic area to double. Knowledge of this makes it possible to determine
what facilities, products, and services a given society will require in the future and the number
of years that its planners have to design, finance and provide these requirements. Total fertility
ratio refers to the average number of children that a woman in the society under study is likely
to have over her lifetime. Knowledge of this ratio is obviously very useful for educational
authorities for example. They need to know how many primary schools will be needed in the
future and how many years they have to build them. Both life expectancy and the infant
mortality rates are useful indications of the well-being of the population generally and of the
health of newborn babies, and officials rely on them to identify health problems and to evaluate
the efficacy of their health policies and practices.

27