Question

Epidemiologists are concerned with population growth as it relates to potential healthcare issues. Why do rates and measures of population change use the “total mid-year population” instead of the “end-of-year population?” What makes one measurement more effective than the other? Choose a real or a hypothetical example to explain how using the “end-of-year population” affects data collection and outcomes.

Answer 1

Rates and measures of population change use the total mid-year population instead of end-of-year population because the mid-year data show the mean for the year, being what has happened in half of the year. This is more effective in that it paints a more accurate picture than end-of-year data.

The mid-year population appears to be the most suitable standard for comparability with regard to time reference; and it is in most cases a practically sufficient approximation for the computation of annual rates, such as birth, death and marriage rates, annual per capita income, production and consumption

For example, if a society gains 10% in population over the course of a year, then the end-of-year data would show far more people there than were actually in the society throughout the year. As such, the mid-year population reveals a more fair understanding.