4.  Demography is scientific study of human
population.
 & Changes within them

5. OR in Population Size & its Composition
in response to:
 Birth
 Aging
 Death
 Migration

6. i Population size (# of persons in pop:)
rapid growth, slow growth, population decline
ii Population Structure: / Composition:
(Division according to characteristic)
(E.g:- Sex structure, Age structure)
ethnic, age, sex (also, how many are non-citizens)
iii Population distribution
% rural, % urban, % suburban. Also, how many
citizens live overseas
Important ‘demographic processes’ include:
fertility, mortality, marriage, education & social mobility.

7. 1960 1970 1980 1990 2000
US 179,323,175 203,211,926 226,545,805 248,709,873 281,421,906
Fl
4,951,560 6,789,443 9,746,324 12,937,926 15,982,378
Ln 74,225 103,047 148,665 192,493 239,452

8. Population Structure: / Composition:
(Division according to characteristic)
(E.g:- Sex structure, Age structure)
ethnic, age, sex (also, how many are non-citizens)
Males Females

9. Population distribution
% rural, % urban, % suburban. Also, how many
citizens live overseas

10.  No: of Live Births (B)
 No: of Deaths (D)
 No: of Immigration / In Migration (IM)
 No: of Emigration / Out Migration (OM)

11. Components of Population Change
(Population Dynamics)
• Demographers rely upon the “Demographic Balancing
Equation” to very simply and elegantly summarize
population change:
Pop2 = Pop1 + B – D + IM – OM, where
Pop2 = Population at a later time period
Pop1 = Population at an earlier time period
B = Births
D = Deaths Migration
Mortality
IM = In-Migration
Fertility
OM = Out-Migration
• The nature of population change is simple… changes can
only occur through: 1) Births, 2) Deaths, or 3) Migration

12. PUSH FACTORS: PULL FACTORS:
Unemployment Attracts the Migrants
Booming economy
Famine
Favorable Immigration
War
laws.
Political or Free Agricultural Land
Religious harassment

13. NI(B-D)+Net Migration(IM-OM)
Natural Increase:
Surplus or deficit of births over death
Net Migration:
Net effect of immigration & emigration ( or )

14.  Population is increased at a given period
of time.
 Effect of natural increase & net migration.
 Expressed in % per year.
 Rapid PGR link to following many problems in less
developed countries.
Hunger inadequacies in social / Health services
Poverty i,e Transportation & communication
High IMR

15. • Number of years it will take for population
to double at current growth rate
70 ÷ Growth Rate = Doubling Time
Growth Rate Doubling Time
Uganda 3.6% 19 years
Afghanistan 2.5% 28 years
India 1.3% 54 years
United States .5% 140 years
Denmark 0.0% --
Russia -0.5% 140 years* (1/2)

16. 1. Census
2. National Survey
3. Registration of vital events
(Births, Deaths ,Marriages , Adoptions, Divorces & separations)
4. Demographic Studies

17. END