Question

Which is best in order to make a comparison between two populations?

• A. Standardised mortality rate
• B. Disease specific death rate
• C. Proportional mortality rate
• D. Age specific death rate

Hint:

Age-adjusted (standardised) rates remove structural differences between populations.

Answer 1

The Correct Option is A

This question tests knowledge of epidemiological measures used to compare mortality between two different populations.

1. Standardised Mortality Rate: This rate is adjusted for age (or other confounding factors) using a standard population, so it removes the bias caused by different population structures. It is the correct tool for a fair comparison.
2. Disease Specific Death Rate: This only reflects deaths from a single disease and gives no correction for age or other structural differences between the two populations.
3. Proportional Mortality Rate: This shows the share of total deaths caused by a given condition, but it is influenced by the overall death pattern and is not a true standardised measure.
4. Age Specific Death Rate: This is useful for one age band at a time, but comparing many age bands separately is not as practical as a single standardised summary figure.

Because crude rates are distorted by differences in age structure between populations, epidemiologists use standardisation to make a fair comparison. The standardised mortality rate is built exactly for this purpose.

Let's summarize:

• Crude rates cannot be compared directly if population structures differ.
• Standardisation adjusts for these differences using a reference population.

So the best measure for comparing two populations is the standardised mortality rate.