DEMOGRAPHY(STUDY OF POPULATION)

Dr sanjeev sahu DPH1

Upgraded Department Of community medicineKing George's medical university, lucknow

DEMOGRAPY DEMOGRAPHY-- is scientific study of human population.

-- is statistical study of human population with regard to their size & structure , their composition by age, sex, marital status & ethnic origin & the changes to these population like changes in their birth rate ,death rate & migration.

POPULATION is the number of person occupying a certain geographic area drawing substance from their habitat and interacting with one another.

HABITAT is natural home.(natural environment of an organism.)

DEMOGRAPHER commonly define population as a collective group of individual occupying a particular place at a given time.

. Three key word are involved in definition of population • group• Place• Time

DEMOGRAPHY It focus on (a) change in population size (growth or decline) (b) composition of population(age,sex,etc) (c) distribution of population

It deals with`5’ “demographic processes” (a) fertility or natality (b) mortality (c) marriage (d) migration (e) social mobility

scientific study of human population

Source of demographic dataIn India main source of demographic data are

Population censusNational sample surveysRegistration of vital eventsAdhoc demographic studies.

Importance of demography & demographic data Demographic data provide a basis for predicting future trends & making decisions. It is also important for formulation, implementation & evaluation of plan ,policies & programs. It guide to policy makers to make policies that can fulfill the needs of various sector of society such as young ,adult, & aged, unemployed, poor & various cultural group.

THEORIES ON POPULATION GROWTH AND DECLINEMALTHUSIAN THEORY (THOMAS MALTHUS 1766-1834 )“An assay n the principle of population” theorized that population was uncontrollable & that it would.Argued that human population are inescapably caught in conflict between their “need for food” and “passion between sexes”. population he maintained increases geometrically (2,4,8,16,…) while food supplies increases only arithmetically (2,3,4,5…..)

MARXIAN THEORY(CARL MARX)Marx believed that problem was not primarily one of population but one of the ownership of the means of production and inequitable distribution of societies wealth.

DEMOGRAPHIC TRANSITION THEORY ( WARREN THOMPSON )

in 1929 the American demographer Warren Thompson observed changes in birth and death rates in industrialized societies over past 200 years or so and then formulated a model called demographic transition , that describes population change over time (demographic cycle).

DEMOGRAPHIC CYCLEit has 5 stages through which each country passes during course of time.

STAGE 4:LOW STATIONARY

STAGE 5:DECLINING

STAGE 1:HIGH STATIONARY

STAGE 2:EARLY EXPANDING

STAGE 3:LATE EXPANDING

STAGE 1 2 3 4 5

K/a HIGH STATIONARY

EARLY EXPANDING

LATE EXPANDING

LOW STATIONARY

DECLINING

B R high unchanged(remains high)

tends to fall Low Lower than DR

DR high Begin to fall Falls further Low Low(higher than BR)

DG (demographic gap)

Narrow Increasing Increased/start decreasing

Narrow Reversal

population Stationary Growing(Increasing rate)

Growing (decreasing rate)

Stationary declining

Population composition

young young young mixed ageing

EXAMPLE India till 1920

Africa India, China Austria, Sweden

Germany ,Hungary

DEMOGRAPHIC CYCLECharacteristic & examples of different stages of demographic cycle

DEMOGRAPHIC CYCLE

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Components of population changeFERTILITY (BIRTHS) :Birth rate :“number of live birth per 1000 estimated mid year population in a given year” birth rate is the simplest indicator of fertility. birth rate (BR) =

number of live birth during a year------------------------------------------- x1000 Estimated mid year population

MORTALITY ( DEATH ) :Death rate : “ number of death per 1000 of total mid year population in a particular place at a specified time”

Death rate(DR) =-----------------------------------x1000Number of death

Mid year population

MIGRATIONMigration is movement of people from one place to another ( within country or specified territory ) for the purpose of taking up permanent or semi permanent residence, usually across a political boundary.

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Birth and death rates in IndiaDeclining birth rates –Changes in government attitude towards growthspread of educationincreased availability of contraceptionfamily planning programschange in marriage patterns

Declining death rate‐improvement in maternal and child health servicesimproved immunizationdiarrhoeal and respiratory disease control programsreduction in infant and child mortality

GROWTH RATE“Change in number of individual in a population pr unit time”

When crude death rate subtracted to crude birth rate, the net residual is current annual growth rate, exclusive of migration.

Annual growth rate = crude birth rate – crude death rate

Annual growth rate Population rating Population doubling time 0 stationary

<0.5% slow growth >139 year

0.5-1% moderate growth >70 year (139 -70)

1-1.5% rapid growth appox.50 year (70 -47)

1.5-2% Very rapid growth appox.40 year (47-35)

>2% Explosive growth < 35 year

On the basis of annual growth rate, population rating & its doubling time

Modified from ,Source : principles of demography john Wiley (1969)

Annual growth rate(AGR)

Annual growth rate = crude birth rate – crude death rate

look the example :

Crude birth rate of India = 21.6 /1000 populationCrude death rate of India = 7 /1000 populationSoAnnual growth rate of India = 21.6 – 7 =14.6 /1000 populationOr =1.46 %

*Note that this is exclusive of migration , as India has very little net migration rate (-0.005%).**annual growth rate of India (census 2011)…..1.64 %

But if we consider migration than…….

Decadal growth rate(DGR): Change in population over a decade**decadal growth rate of India (census 2011)….17.64 %

**decadal growth rate in Uttar Pradesh………20.1%

Migrant is a person who at the time of census is residing at a different place than his/her place of birth.

Marriage being the most common reason for females and employment for males .

Census 2001 total no of migrants 314 million in India

Immigration: People moving in to another country Emigration: People moving away from their home country.

*If you were to move to England, you would be emigrating from India and immigrating into England.*

Migration is movement of people from one place to another for the purpose of taking up permanent or semi permanent residence, usually across a political boundary

MIGRATION

ROLE OF MIGRATION IN POPULATION GROWTHPush-Pull Factor

there are two things that affect population: Fertility/Mortality rate , :Migration rate .

Population Growth rate = Rate of natural increase + net migration rate

Rate of natural increase = Birth rate – Death rate

Doubling Time: The amount of time it takes for a country’s population to double

- Generally known as the Rule of 70:

70 / Population Growth Rate = doubling time

Net migration rate(India)−0.05 migrant(s)/1,000 population (2007 est.)

Country Population (Millions)

Birth Rate per 1000

Death Rate per 1000

Natural Increase per 1000

% Natural Increase

India 1,214,464,000(1.214 billion)

23.0 8.5 14.5 1.45%

Rate of Natural Increase (%)

How to calculate: look the example

Exercise:

Country Population (Millions)

Birth Rate per 1000

Death Rate per 1000

Natural Increase per 1000

% Natural Increase

Russia 140,367,000 10.8 15.1

Country Rate of natural increase (%)

net migration rate(%)

Population Growth rate (%)

India 1.45 -0.005 1.45-0.005=1.44

Population growth rate including migration:

*net migration rate of indiça:−0.05 migrant(s)/1,000 population (2007 est.)

Country Rate of natural increase (per 1000)

net migration rate(per 1000)

Population Growth rate( per 1000)

India 14.5 -0.05 14.45

*** population growth per 1000 is 14.45Hence, population growth per individual =14.45/1000So, population growth in %=14.45x100/1000 =1.445 %

GROWTH TREND OF INDIA

Population growth of

Indiaslower 1921 rapid

k/aGreat divide

1991 Slight fall 2001Further

fall 2011

**

**better nutrition & improved health care declined death rate more steeply than birth rate. This result in net gain in birth over death leading to rapid growth.

***recent data suggest decline in India population growth rate, India's population currently increasing at a rate of 16 million each year.

*slower growth prior to 1921 in India is due to natural checks (eg. Famines & epidemics ).

*Famines , epidemics

Important definitions in demography

Crude birth rate(CBR): annual no. of live birth per 1000 mid year population.Crude death rate(CDR): annual no. of death per 1000 mid year population.General fertility rate(GFR):Annual no. of live birth per 1000 women of childbearing age (15-44 or 49 year old )mid year population.General marital fertility rate (GMFR): number of live births per 1000 women in reproductive age group(15-44 or 49) in a given year.Age specific fertility rate (ASFR):number of live births in a year to 1000 women in any specified age group.Total fertility rate (TFR):number of children a woman would have if she were to pass through her reproductive years bearing children at the same rates as the women now in each group. (it give approx magnitude of “completed family size”).Net reproduction rate (NRR): number of daughters a newborn girl will bear during her lifetime assuming fixed age specific fertility and mortality rates.(it is a demographic indicator.NRR 1 is equivalent to attaining approx 2 child norm.)

India is the second most populous country in the world, with over 1.277 billion people (2015), more than a sixth of the world's population.

Already containing 17.5% of the world's population, India is projected to be the world's most populous country by 2022, surpassing China, its population reaching 1.6 billion by 2050. (source:"India's population 'to be biggest' in the planet". BBC News. 18 August 2004. Retrieved 2011-09-24. . : US Census Bureau, Demographic Internet Staff. "United States Census Bureau - International Data Base (IDB)". Census.gov. Retrieved 2011-09-24.)

DEMOGRAPHIC TRENDS IN INDIA

India occupies 2.4% of the world’s land area but supports over 17.5% of the world’s population.At the 2001 census 72.2% of the population lived in villages and the remaining 27.8% lived in towns and urban areas.Uttar Pradesh is most populous state in India followed by Maharashtra and Bihar with 16.46% of total population of India(2011) Maharashtra 9.29 % and Bihar 8.58%

WORLD INDIAPOPULATION 7238 Million (2014) 1210 million (2011)

CBR 19.9/1000 Population (2012) 21.4 (2014)

CDR 8.37 (2011) 7.0 (2014)

GROWTH RATE 1.17% (2014) 1.64% (2011)

LITERACY RATE 82% (2007) 74.4% (2011)

World vs. India

Demographic trends in IndiaDemographic indicatorAge & sex compositionSex ratio Dependency ratioDensity of populationUrbanizationFamily sizeLiteracy & educationLife expectancy

Demographic indicatorThese indicator help in - identification of that area which need policy or programmed intervention. -setting near & far term goals & deciding priorities.

DEMOGRAPHIC INDICATOR POPULATION STATISTIC VITAL STATISTIC

Population sizeSex ratioPopulation densityDependency ratio

Birth rateLife expectancy at birthMortality rate Fertility rate

AGE &SEX COMPOSITION0–14 years: (30.8% ); male: 188,208,196, female:171,356,024 (Male > female)15–64 years: (64.3%); male: 386,432,921, female:364,215,759 65+ years: (4.9%); male: 27,258,259, female: 30,031,289 (female >male)Médian âge25.1 yearsProportion of population below 14 showing decline whereas population of elderly increasing

AGE PYRAMIDSA population pyramid tells us what portion of a population are within a

given age cohort.

70-8060-7050-6040-5030-4020-3010-20 0-10

male female

4 3 2 1 1 2 3 4

Population pyramids can also tell us what stage of development a country is at.

Early Expanding •Wide base (lots of young children)

and a very narrow top (few old people).

•Very high birth rate and death rate (short life expectancy).

•Reasons could include poor health care, lack of family planning, need

for children as workers.• Corresponds to stage 1 – 2 of DTM

ExpandingSlightly narrower base than early expanding and a little wider in the middle

and older ages. Birth rate still high but decreasing slightly and death rate decreasing.

Reasons for the change from early expanding could include better medical care, improved diet and better hygiene.

Roughly corresponds with stage 3 of the demographic transition model.

Stable: Bottom part of pyramid is close to a vertical line.

Birth rate falls while death rate also falls and they are in balanceReasons could include better health care, improved family planning, better

economic conditions.Roughly corresponds with stage 4 of the demographic transition model

Contracting: Bottom part of pyramid narrower than the middle and continually getting

narrower.Birth rate continues to fall while the death rate continues to decrease.

Reasons could include more women working, high cost of child rearing, small families encouraged by the state.

Examples: Germany/ Japan.Roughly corresponds with stage 5 of the demographic transition model.

Male to female sex ratio for India, based on its official census data, from 1941 through 2011.(source:“Sex Composition of the Population”, Office of Registrar General and Census Commissioner of India, Ministry of Home Affairs, Government of India (2013). )

SEX RATIO“Number of females per 1000 males”

Natural sex ratio at birth =950 (estimated) ( it can be effected by sex selection at birth )

SEX RATIO ‘number of female per 1000 male’Sex ratio in India (census 2011)…. 940 rural……………………947 urban………………….926

Child sex ratio (0-6 year ) : no. of female child per 1000 male child (in 0-6years age) : CSR in India (2011)…..914 (highly unfavorable)

sex ratio in India adverse to women & also decliningfemale deficit syndrome has social implications*highest sex ratio Kerala (1084) lowest Haryana ( 877)Sex ratio in Uttar Pradesh = 908. (rural 914 ,urban 883 ).

Low sex ratio indicate strong male child preference & its consequence is gender inequality ,female infanticide / feticide & neglect of child girl.

DEPENDANCY RATIODependent age group ---- >65 & <15 yearEconomic productive group ---- 15-64 year

the proportion of persons above 65 yrs of age and children below 15 yrs of age are considered to be dependent on economically productive age group (15-64 years)

Total dependency ratio* = -------------------------------------------------------------x 100Children ( 0-14 years) + population >65 years

Population 15 -64 years* Also k/a societal dependency ratio.

Demographic bonusPeriod when the dependency ratio in a population declines because of decline in fertility, Until it starts to rise again because of increasing longitivity.It gives push to development.

Demographic burdenThe increase in total dependency ratio during any period of time .Mostly Caused by increased old age dependency ratio.This is unavoidable consequence of demographic transition, country has to face problem sooner or later.

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Population density“number of person , living per sq. kilometer” (census of India)

Current trends in population density in India ---- RISECensus 2011 …….total population in India :1,210 million rural :833.1 million (68.84 %) urban :377.1 million (31.80 %) Population density…..382 (person per sq. km.) (census 2011)

Number of states/union territories---35 Numbers of distt.------640 Number of villages----6.41 lacs * highest population : Uttar Pradesh (199 million);with population density(828). :highest population density Delhi(11,297)

Urbanizationurban population : number of persons residing in urban localities.“TOWNS”--- Places with municipal corp. , municipal area committee , town committee , notified area or cantonment board.“all places having 5000 or more inhabitants ,a density of not less than 1000 persons per sq. mile or 390 per sq. km. , pronounced urban characteristics and at least ¾ of adult male population employed in pursuits other than agriculture.”

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Rise in urban population is due to natural growth (birth) & migration from village because of employment , better living conditions, education ,health facility , transport ,entertainment etc.

In India : major population is rural and their main occupation is agriculture.

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FAMILY SIZEIn general family size represent : total number of person in a family.

Demographically: total number of children a woman has born at a point of time

completed family size :total number of children borne by a woman during her child bearing age (15 – 45 years)*

Total fertility rate gives approx. magnitude of completed family size.Long term demographic goal is net reproduction rate (NRR) = 1 ,** which means “ 2 child family norm”.NET REPRODUCTION RATE (NRR) : “no of daughters a newborn girl will bear during her lifetime , assuming fixed age specific fertility and mortality rates”

Family size depends on‐ duration of marriage ‐ education of couple ‐ no. of live births and living children ‐ preference of male children ‐ desired family size.

*child bearing age gen. assumed in between 15 and 45 years. **NRR=1 each woman will reproduce exactly 1 girl.

Literacy and education education is crucial element of economic and social developmentLiteracy is generally associated with‐ modernization ‐ urbanization ‐ industrialization ‐ communication and ‐ commerceliterate‐ the one above 7 years of age and can read and write with understanding in any Indian languagethere is major improvement in literacy status in India.• government of India has made education compulsory up to the age of 14 years in the country.

Literacy rate(India)74% (age 7 and above, in 2011)81.4% (total population, age 15-25, in 2006)82% male ,65% femaleMaximum Kerala 92% , least Bihar 64% Uttar Pradesh 69.72 (male 79.24 ,female 59.26)

LIFE EXPECTANCY is the “average number of years which a person may expect to live”Age specific life expectancy : life expectancy at a given age is average number of years which a person of that age may expect to live.

It is one of the best indicator for a country to measure it development &health status of its population.Life expectancy :Female >male*in India life expectancy of female is almost same male.

Life expectancy at birth in IndiaTotal population : 65.8 years (source: UN Human Development Report ,2013 )

Few key findings (demographic) of NFHS-3 (INDIA-2005-2006)TFR=2.68.Literacy rate: male 83% , female 59%Population composition- 0-14 years-----34.9% 15-49years----49.5 50-59years ---7.1% 60 or more ---8.5%

Findings of SRS bulletin (2013)Crude birth rate =21.6/ 1000 mid year population

Crude death rate =7/ 1000 mid year population

natural growth rate =14.5/ 1000 mid year population

Infant mortality rate =42/1000 live birth

Net reproduction rate =1.14

FERTILITY / NATALITYFertility means actual bearing of childrenA woman reproductive period is roughly from 15 -45 years .( 30 years)Fertility depend upon

1. Age at marriage : if age at marriage is <18-----more children. >18 (20-21)----no. of birth decreases by 20 – 30 %

Sarada act (1929) was enacted forbidding the child marriage. child marriage restraint act----- it raises legal age for marriage from 15 to 18 for girls (1978) 18 to 21 for boys

2. Duration of married life: With in 1-5 years of marriage ……. 10 – 20 % of all birth

5-15 years ……. 50-55 % After 25 years …….. Very few

*family planning effort at initial few period of marriage can achieve desired result3. Spacing in children : postponement of birth by 1 year decline fertility accordingly

4. Education : fertility is in inverse association to education . :Education provides knowledge , increased exposure to information and Media , build skill, increase power in décision making.

5.Economic status : fertility is inversely proportional to economic status . 6. Cast & religion :fertility in Muslim (TFR 3.09) > Hindu (2.65) > Christians (2.35)

Among Hindus lower caste have higher fertility than upper caste 7. Nutrition ‐well‐ fed societies have low fertility

8. Family planning‐key factor in declining fertility

9. others‐no. of physical, biological, social and cultural factors play role

"India set to overtake China as world's most populated country after adding 180m people in a decade". Daily Mail (London). 31 March 2011.

"India's population 'to be biggest' in the planet". BBC News. 18 August 2004. Retrieved 2011-09-24.

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