CBR, CDR, GR, LE, Sex ratio, Dependency Ratio, GFR, ASFR, TFR, GRR, NRR - important demographic and fertility indicators practical class

1. DrTanveer Rehman
Senior Resident
Dept of Community Medicine & Family Medicine

2. Overview
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DRTANVEER REHMAN, CMFM, AIIMS-K

3. Overview
• Governments need to know how many inhabitants currently live in the
country and how many there will be in the future.
• From this they can plan and make better decisions regarding the
construction of schools, hospitals, roads etc.
• Governments also need to know how old the population is and will be in the
coming years in order to plan for pensions, health care etc.
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DRTANVEER REHMAN, CMFM, AIIMS-K

4. Overview
• Crude – unrefined/ grossly, not accounting age & gender, like CBR 15 means
1000 population gives 15 births, but those 1000 aren’t giving birth, maybe
500 women
• Population India: 439 million (1961) – 30 years doubled to 846 m (1991)
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DRTANVEER REHMAN, CMFM, AIIMS-K

5. POPULATION
• Denominator: grandpa smokes daily yet 90
years old – unimportant: check the proportion
surviving
• India – 1.39 billion ~ 20% of world
• By 2050 ~ 1.53 billion
• “Big divide” – 1921
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6. CRUDE BIRTH RATE
• The ratio of births in a year (other specified period) to the average population
in the same year/period (mid-year population), expressed per 1000:
• India – 20.0, Bihar - 26.2,West Bengal – 15.0
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DRTANVEER REHMAN, CMFM, AIIMS-K

7. CRUDE DEATH RATE
• The ratio of deaths in a year (other specified period) to the average
population in the same year/period (mid-year population), expressed per
1000
• India – 6.7, Chhattisgarh 8.0, West Bengal – 5.6
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DRTANVEER REHMAN, CMFM, AIIMS-K

8. POPULATION GROWTH RATE
• Current annual growth rate = (Crude birth rate – crude death rate)/
10
• Excusive of migration
• Population doubling time for 1% to 1.5% annual growth rate – 70
to 47 years
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9. LIFE EXPECTANCY
• Average number of years a person of that age may expect to live
according to mortality pattern prevalent
• In 1950 ~ 47 years in India
• Highest in Switzerland (Males 82 years, females 85 years)
• India: Males 68 years, females 70 years
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DRTANVEER REHMAN, CMFM, AIIMS-K

10. Sex Ratio
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1. Usually denoted by number of girls for every 1000 boys
2. Primary sex ratio: conception stage
3. Secondary sex ratio: birth stage
• Skewed towards boys – biological bias & female deficit syndrome
4. Tertiary sex ratio: adult stage
• Skewed towards boys – Female deficit syndrome
5. Quaternary sex ratio: post reproductive organs
• Skewed towards women
DRTANVEER REHMAN, CMFM, AIIMS-K

11. LITERACY RATE
• Can read, write & understand at least one language
• India – 73%, Bihar 62%,West Bengal – 76.3%
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13. SEX RATIO
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1. Usually denoted by number of girls for every 1000 boys
2. Primary sex ratio: conception stage
3. Secondary sex ratio: birth stage
• Skewed towards boys – biological bias & female deficit syndrome (due to feticide,abortion)
4. Tertiary sex ratio: adult stage
• Skewed towards boys – Female deficit syndrome
5. Quaternary sex ratio: post reproductive organs
• Skewed towards women
DRTANVEER REHMAN, CMFM, AIIMS-K

14. Dependency ratio
• Current annual growth rate = (Crude birth rate – crude death rate)/ 10
• Excusive of migration
• Population doubling time for 1.5% to 2.0% annual growth rate – 47 to 35
years
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DRTANVEER REHMAN, CMFM, AIIMS-K

15. Dependency ratio (DR)
• Demographic bonus: with early development, fertility decreases more than
old population increases, so DR decreases – push for education & health care
• Demographic burden: Eventually with fertility decreasing & life expectancy
increasing – child DR shifts to old age DR
• Child DR: 26, Old age DR: 6.6,Total DR: 48.7%
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DRTANVEER REHMAN, CMFM, AIIMS-K

16. Sex Ratio
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1. Usually denoted by number of girls for every 1000 boys
2. Primary sex ratio: conception stage
3. Secondary sex ratio: birth stage
• Skewed towards boys – biological bias & female deficit syndrome
4. Tertiary sex ratio: adult stage
• Skewed towards boys – Female deficit syndrome
5. Quaternary sex ratio: post reproductive organs
• Skewed towards women
DRTANVEER REHMAN, CMFM, AIIMS-K

17. FERTILITY
• Fertility or family size in this context: total number of children a woman
borne at a point of time
• Completed family size: total borne in her reproductive age period 15-45/49
years
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DRTANVEER REHMAN, CMFM, AIIMS-K

18. CRUDE BIRTH RATE
• The ratio of births in a year (other specified period) to the average population
in the same year/period (mid-year population), expressed per 1000:
• India – 20.0, Bihar - 26.2,West Bengal – 15.0
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DRTANVEER REHMAN, CMFM, AIIMS-K

19. GENERAL FERTILITY RATE
• Births to women aged 15–44/49 in a year/period per 1000 women aged 15–
44/49 in the same period
• Not all women are at risk of childbirth – General Marital Fertility Rate
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DRTANVEER REHMAN, CMFM, AIIMS-K

20. AGE-SPECIFIC FERTILITY RATE (ASFR)
• Average number of children a woman would have if she were to pass through
reproductive years bearing children at same rate as women now in each age
group
• ASFRs are frequently calculated for 5-year age groups from 15–19 to 40–44 or
45–49
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DRTANVEER REHMAN, CMFM, AIIMS-K

21. TOTAL FERTILITY RATE (TFR)
• The sum of the ASFR for all reproductive age groups for a particular period
(usually a year), conventionally expressed per woman
• Indicates how many children a woman would have if throughout her
reproductive life, she had children at the ASFR
If x=49
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22. TFR continuing…
• ‘ fx’ is the ASFR at age x
• If rates for age groups, rather than single years, are used then the sum of the
ASFR must be multiplied by the number of single ages included in the group
(usually five).
If x = 45–49:
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DRTANVEER REHMAN, CMFM, AIIMS-K

23. GROSS REPRODUCTION RATE (GRR)
• Sum of the age-specific female fertility rates (births of daughters), for all
reproductive age groups for a particular period (usually a year) conventionally
expressed per woman
• The GRR indicates how many daughters a woman would have if, throughout
her reproductive life, she had children at the ASFR prevalent in the specified
year of period
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DRTANVEER REHMAN, CMFM, AIIMS-K

24. NET REPRODUCTION RATE (NRR)
• Average number of daughters that would be borne, according to specified
rates of mortality and ASFR, by a new-born female
• The NRR employs the same fertility data as the GRR, but also takes into
account the effects of mortality.
• An NRR of 1.0 indicates that a population’s fertility and mortality levels would
result in exact replacement of mothers by daughters – 2 child norm
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DRTANVEER REHMAN, CMFM, AIIMS-K

25. TOTAL FERTILITY RATE (TFR)
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GROSS REPRODUCTION RATE (GRR)
NET REPRODUCTION RATE (NRR)
Total number of children born (males and females)
Total number of females born
Total number of females born who survived till
age 15-45/49 years
DRTANVEER REHMAN, CMFM, AIIMS-K

26. Exercises
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27. Reference
1. Detels R, editor. Oxford textbook of global public health. Oxford
Textbook; 2015
2. National Health Profile 2020. Central Bureau of Health Intelligence,
Directorate General of Health Services, Ministry of Health & Family
Welfare. Government of India, New Delhi 2020.
3. Park K. Park's textbook of preventive and social medicine. Jabalpur.
Banarasidas Bhanot. 2020.
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DRTANVEER REHMAN, CMFM, AIIMS-K