Question

Direct standardisation is used to compare the mortality rates between two countries. This is done because of the difference in:

• A. Causes of death
• B. Numerators
• C. Age distribution
• D. Denominators

Hint:

Standardisation removes the confounding effect of one demographic variable between populations.

Answer 1

The Correct Option is C

Step 1: Understand crude mortality rates.
A crude death rate lumps together all ages. When two populations differ in their age structure, comparing crude rates is misleading, because mortality rises sharply with age and a population with more elderly people will appear to have higher mortality regardless of actual risk.

Step 2: Role of standardisation.
Standardisation removes the confounding effect of age. In direct standardisation, the age-specific death rates of each study population are applied to a single common (standard) population age structure, producing age-standardised rates that can be compared fairly.

Step 3: Identify the difference being corrected.
The whole purpose is to adjust for the difference in age distribution between the two countries. It does not correct for differences in causes of death, numerators, or denominators per se.

Step 4: Conclusion.
Direct standardisation accounts for differences in age distribution (option C). This matches the printed key.