Which statement best defines a case definition in outbreak surveillance?

• A. A precise, standardized set of criteria used to classify whether a person has the disease.
• B. A list of all attendees at an event.
• C. A statistical model used for predicting outbreaks.
• D. A description of the outbreak's timeline.

Answer: (C)

A case definition is a precise, standardized set of criteria used to determine whether a person has the disease in question. This standardization ensures that every suspected, probable, or confirmed case is identified using the same rules, which makes surveillance data comparable over time and across locations. Case definitions often combine clinical features, laboratory results, exposure history, and time/place criteria, and may include different categories (suspected, probable, confirmed). This consistency reduces misclassification, helping public health teams accurately track the outbreak’s size, spread, and trends.

The other options describe different concepts: a list of event attendees is an attendance roster, a statistical model for predicting outbreaks is predictive analytics, and a description of the outbreak’s timeline is a chronology of events. None of these define how to classify cases for surveillance.