Define Mortality: The following rates are used for measuring mortality.
Crude death rate
The annual crude death rate is defined as
Crude death rate = annual deaths / annual mean population x 1,000
Specific death rates
The formula for computing specific death rate is:
Number of deaths which occurred among a specific age group of the population of an annual death rate specific for age = given geographic area during a given year / mid- year population of the specified age group in the given geographic area during the same year x 1,000
Illustration:- compute the crude and standardized death rates of the two populations A and B from the following data
Age - group (years) |
A |
B |
|
Population deaths |
Population deaths |
Below 5 |
15000 360 |
40000 1000 |
5 - 30 |
20000 400 |
52000 1000 |
Above 30 |
10000 280 |
8000 240 |
Total
|
45000 1040 |
100000 2280 |
Solution:-Crude death rate = N / P x 1000, where N = No. of deaths, P = population
C.D.R for town A = 1,040 / 45,000 x 1,000 = 23.11
C.D.R. for town B = 2,280 / 1, 00,000 x 1,000 = 22.80
Standardized death rate (town A) = (15000 x 24) + (20000 x 20) + (1000 x 28) / 15000 + 2000 + 1000
= 360000 + 400000 + 280000 / 45000 = 1040000 / 45000 = 23.11
Standardized death rate (town B) = (15000 x 25) + (20000 x 20) + (10000 x 30) / 15000 + 20000 + 10000
= 375000 + 400000 + 300000 / 45000 = 1075000 / 45000 = 23.89We can now say that the death rate in town B in higher than in town A.
Another method of computing standardized death rate is to take some assumed population (that is the population of neither town A nor B) as standard, but this method is not so popular
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