Mortality measures, including definitions, formulas and interpretations – Track2training

Detailed explanation key Mortality measuresincluding definitions,, formulasAnd interpretations For:

• Coarse mortality
• Specific age mortality rate
• Infant mortality rate
• Neonatal mortality rate
• Adjusted / standardized mortality rate

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1. Gross mortality rate (CDR)

Definition::

The gross mortality rate is the total number of deaths in a population over a given period (generally one year) for 1,000 people.

Formula::

Example::

If a country has 50,000 deaths in one year and a mid-year population of 5,000,000: CDR =?

Boundaries::

• Does not take into account the age structure of the population.
• Can be misleading when comparing countries to different age demographic data.

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2. Age specific mortality rate (ASDR)

Definition::

ASDR measures the mortality rate within a specific age group for 1,000 people in this group.

Formula::

Example::

If there are 500 deaths among people aged 65 to 74 and that the population of this group is 50,000: ASDR =?

To use::

• Helps identify high -risk age groups.
• More precise than the gross mortality rate for planning and health analysis.

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3. Infant mortality rate (IMR)

Definition::

The IMR refers to the number of deaths of infants under a year for 1,000 living births during a given year.

Formula::

Example::

If 1,200 infants die in a year and there were 100,000 living births: IMR =?

Importance::

• Reflects the quality of health care, nutrition and maternal health.
• A key indicator of social and economic development.

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4. Neonatal mortality rate (RMN)

Definition::

The RMN refers to the number of infants' deaths in the first 28 days of life for 1,000 living births.

Formula::

Example::

If there are 600 deaths within 28 days among 100,000 living births: RMN =?

To use::

• Assesses the quality of prenatal and immediate postnatal care.

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5. adjusted or standardized mortality rate (DTS)

Definition::

The standardized mortality rate adjusts the gross mortality rate to eliminate the effects of age distribution differences. It allows a comparison between populations with different age structures.

Why normalize?

Populations with more elderly people will naturally have higher raw mortality rates, even if the health system is good. Standardization reports it.

Standardization methods::

Two common methods:

• Direct standardization
• Indirect standardization

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A. Direct standardization

Formula::

Measures::

1. Multiply each specific age mortality rate by the standard population for this age group.
2. Summarize all products.
3. Divide by the total standard population.

To use::

• To compare mortality between countries or over time, use a common standard.

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B. Indirect standardization (Often used when specific age rates are not available)

Measures::

1. Use specific mortality rates at the age of standard population.
2. Apply them to your study population to find the expected deaths.
3. Compare the deaths observed in relation to the expected deaths.

Standardized mortality ratio (SMR)::

• SMR = 100: Mortality is equal to the standard.
• SMR> 100: higher than standard mortality.
• SMR <100: mortality lower than the standard.

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Summary table:

References

Kumar, G., Vyas, S., Sharma, SN and Dehalwar, K. (2025). Environmental health challenges in waste management for peri -urban areas. In Solid waste management: progress and trends to tackle the SDGs (pp. 149-168). Cham: Swiss Springer Nature.

Morris, RF (1957). The interpretation of mortality data in studies on population dynamics1. Canadian entomologist,, 89(2), 49-69.

Ogbanga, MM and Sharma, SN (2025). Climate change and mental heat. Educat

Siegel, JS (2011). Basic concepts and measures of mortality. In Demography and epidemiology of human health and aging (pp. 73-134). Dordrecht: Springer Netherlands.

Sheil, D., Burslem, DF and Alder, D. (1995). The interpretation and the erroneous interpretation of mortality rate measures. Journal of Ecology331-333.

Stocks, P. (1944). Measurement of morbidity.

Sharma, SN, Dehalwar, K., Yadav, K., and Verma, D. (2025). Turbulence of urban street and dispersion of vehicle pollution.

Zeighami, EA and Morris, MD (1983). The measurement and interpretation of proportional mortality. American Journal of Epidemiology,, 117(1), 90-97.