Week 5: Measuring Mortality

Question 1

How do we calculate the crude death rate?

Answer 1

(total deaths in a year/ mid-year population) * 1000

Question 2

Why is this an inefficient measure of mortaility?

Answer 2

Different populations have different age structures, those with an older age structure are more likely to have a higher death rate.

Question 3

How do we calculate age specific mortality rates?

Answer 3

For a single year of age:
Deaths to persons aged x / Mid-year population aged x (* 1,000)

Question 4

How do we calculate the infant mortality rate?

Answer 4

(Deaths under age 1 in a year/Live Births in a year ) * 1,000

Question 5

List the other types of infant mortality rates that can be calculated.

Answer 5

• Stillbirth rate
• Perinatal mortality rate
• Neonatal mortality rate
• Post-neonatal mortality rate

Question 6

How do we account for the differences in age structure of a population for crude death rates?

Answer 6

Standardisation.

Question 7

How does the direct method of standardisation work?

Answer 7

• Apply age-specific rates observed in the populations of interest (e.g. Camden) to a reference or standard population (e.g. England) in order to obtain the number of deaths expected in the reference population
• Calculate an age-adjusted rate based on expected number of deaths in the reference population

Question 8

How does the indirect method of standardisation work?

Answer 8

• Apply age-specific reference rates to the populations of interest to obtain the number of expected deaths in each of those populations
• Compare the observed number of deaths to the expected number of deaths for each population of interest

Question 9

When should we use the direct method of standardisation?

Answer 9

When comparing populations has advantage that all the standardised rates being compared are based on the same standard population structure.

Question 10

List a disadvantage of using the direct method.

Answer 10

Requires separate set of ASDRs for each population of interest, which may not be available for small populations.

Question 11

List an advantage of using the indirect method of standardisation.

Answer 11

• Only need one set of ASDRs (for the standard) and just need population structure and total deaths for populations of interest.
• Generally a better option for comparing small populations - standard population is ‘bigger’ so age-specific rates more reliable because based on more deaths