Introduction to demography
- A scientific and mathematical study of the population is known as demography.
- John Graunt is the father of demography.
Introduction to demographic components:
- The factors which cause a change in the size of the population of a place.
- Birth, death, and migration are known as demographic components.
Introduction to demographic process
- The elements which cause the occurrence of demographic components is known as the demographic process
- The demographic process is fertility, mortality, and migration.
Demographic measurement:
- The methods of using demographic statistics and certain formulae to calculate and analyze the fertility, mortality, and migration rate.
- Measurement of Fertility: Fertility is a process that causes a change in population
- CBR= 1000
Where, CBR = crude birth rate
B= total number of live birth in a place in a given year
P = mid-year population of the given place
- Mid-year population(p)=
- Formula to calculate GFR = 1000
Where,
GFR = general fertility rate
B= total no. of live birth
P= mid-year population of the female having fecundity of that place
- Formula to calculate ASFR=
Where, ASFR= age specific fertility rate
Ba = total number of live birth given by females of a certain age or age group having fecundity at the place in a specific year
= total mid-year population of that place of female
- Formula to calculate total fertility rate
TFR =
Where,
S= time interval between lower and the higher margin of an age group
= sum of all the age specific fertility rate of the place in the given year
1000= if the ASFR are measured in per thousand population.
Note: total fertility rate is the number of babies born by individual females of a place within their life span, which is calculated by adding all the ASFRS of the place of a year multiplying it by and divide the overcome by 1000.
- Measurement of mortality
- Mortality is a demographic process which is responsible for population decrease.
- Crude death rate (CDR) is total number of death occurring at a place per thousand people in a specified year.
- Formula to calculate CDR = 1000
Where,
CDR = crude death rate
D = total number of deaths occurring at a place in a specific year
P = mid-year population of that place in a specific year
- Age specific death rate (ADSR) is the total number of people dying at a place within specific year time period belonging to a certain age group in per thousand population of the same age group.
- Formula to calculate ASDR = 1000
Where,
= total number of death of people at a place within a year belonging to certain group.
= total mid-year population of the people at the same age group.
- Infant mortality rate
- Infant mortality rate refers to the death of children below the age of 1 year.
- Formula to calculate IMR = 1000
Where,
= total no. of infant death in the given place within specific year
= total number of live births happening in that place in the year.
- Maternal mortality rate
- The ratio of total death of mother caused by pregnancy and maternity related causes per lakh lives births in a place within a given year .
- Formula to calculate maternal mortality rate:
- MM ratio = 1000
Where,
= total numbers of mothers dead at a place within a year due to pregnancy or maternity related causes
= total number of live birth taking place at that place in the given year.
- Measurement of migration
- In and out migration to and rom a place cause change in population growth.
- In migration rate
Formula to calculate in migration rate = 1000
Where,
P= mid-year population of the place
I = number of in migrants
- Out migration rate
Formula to calculate out migtration rate = 1000
Where,
P= mid-year population of the given year
O= number of out migrants
- Gross migration rate
GMR = 1000
Where,
I = total number of in migrants in the place within the given year
O = total number of out migrants from the place within the given year
P = mid-year population of the place
- Net migration ratr
- NMR= 1000
where,
I = total number of in migrants in the place within the given year
O = total number of out migrants from the place within the given year
P = mid-year population of the place
- Other measurements
- Ratio of natural increase (RNI)
Formula to calculate RNI =
- Population growth rate(PGR)
PGR = RNI ± 100
- Population doubling time (PDT)
PDT =
Where, PGR = population growth rate
- Dependency ratio (DR)
Formula to calculate DR = 100
Where,
= population aged from 0 to 14 years
= population aged 60 and above
= population aged from 15 to 59 years
- Sex ratio (SR)
- The number of males in every hundred population of female in a place at a particular time
- Formula to calculate SR = 100
Where, = total population of male
= total population of female
