Descriptive epidemiology includes which of the following?

• A. Incidence and prevalence calculated
• B. Randomized clinical trials
• C. Investigating causality between exposure and outcome
• D. Laboratory experiments

Answer: (A)

Descriptive epidemiology describes how disease is distributed in a population across person, place, and time, using simple measures. The most representative calculations are incidence and prevalence, which quantify new cases over time and total existing cases at a given time, respectively. These metrics reveal patterns and burden in the population, such as differences by age, sex, geography, or over seasons, and form the core of describing disease occurrence. The other options involve study designs or approaches that test hypotheses about causality or mechanisms rather than simply describing how disease is distributed. So, calculating incidence and prevalence best fits descriptive epidemiology.