What is the difference between point prevalence and period prevalence?

• A. Point prevalence measures cases over a period.
• B. Point prevalence measures cases at a single point in time; period prevalence measures cases over a defined period.
• C. Point prevalence is a measure of mortality.
• D. Period prevalence measures the number of deaths.

Answer: (D)

Understanding prevalence types: point prevalence vs period prevalence. Point prevalence is a snapshot: the proportion of people who have the condition at a single moment in time. Period prevalence, on the other hand, covers a defined time interval and includes anyone who has had the condition at any time during that period, usually expressed as a proportion of the population over that interval.

So the best statement is that point prevalence measures cases at a single point in time, while period prevalence measures cases over a defined period. The other options misstate the concept: point prevalence is not about a period of time, it is not a mortality measure, and period prevalence is not simply the number of deaths.