This PowerPoint talks about meaning of demography and its importance for students of public health and community medicine

1. Demography
DR NISHANT KUMAR
ASSISTANT PROFESSOR
DEPARTMENT OF COMMUNITY MEDICINE
MADHUBANI MEDICAL COLLEGE , MADHUBANI , BIHAR

2. Introduction
 Demo – Population ; Graphy – Study
Demography is branch of community medicine , which deal with the
study of human population in a given area, usually a country , during a
given year , with reference to size, composition , behavior , and
distribution.

3. Introduction(contd.)
Size : It refers to total number of persons residing in the country , which
can be enumerated by census. Thus “size” refers to quantity of population.
Composition : It refers to break down of population into according to
age, sex, marital status, language spoken , religion ,etc. Thus composition
refers to the quality of population.

4. Introduction(contd.)
Behavior: It refers to the ‘growth’ of the population over a period of
decades.(i.e. positive or negative growth). It can be estimated through
population projections ( growth rate of population is the difference
between birth rate and death rate) .Growth rate when expressed in
number it is called “demographic gap” .

5. Introduction(contd.)
 Distribution : It refers to the density of population per km2 , rural –
urban ratio and location of the dense or sparse pocket of population.

6. Determinants
Birth and
Death
Migration
&
Social
mobilizatio
n
Marriage
The statistical study of all the
components of the population
and the factors related to it is
called ‘Demographic statistics’
The term ‘Vital statistics’
refers to vital events like
birth , death, disease,
marriage and divorce

7. DemographicCycle
The trends of population growth in a country undergoes changes or variation
in a step wise manner. These variation are called as ‘steps of demographic cycle’.
There are five stages in a demographic cycle.
It requires several centuries lasting several decades to undergo each cycle.
A country does not pass through the stage one once again in a cyclic fashion
after the fifth stage is over and hence the term ‘cycle’ is misnomer.
The occurrence of change in growth of the population in various stages is
called “Theory of demographic transition”, or “Theory of demographic cycle”.

8. DemographicCycle
S no Stages Characteristics Annual Growth rate
1. First Stage ( High Stationary) High birth rate and high death
rate
In India before 1921.
BR=49.2/1000;
DR=48.6/1000;
GR=0.6/1000.
2 Second Stage( Early
Expanding)
Death rate begin to decline and
birth rate remain the same
India(1921-
BR-49/1000;
DR-36/1000;
GR-13/1000.(1.3%)
3 Third Stage (Late
Expanding)
Death rate decline further and
birth rate start declining
India has entered this
phase ( current GR is
1.34%)
4 Fourth Stage ( Low
Stationary)
Birth rate rapidly falls and
becomes equal to death rate.
GR is 0%, countries like
UK, Australia,Belgium)
5 Fifth Stage(Stage of
decline)
Death rate is higher than the
birth rate
GR less than
0%(minus).Germany and
Hungry are in the stage.