What is the time horizon in economic evaluation?

• A. The duration over which costs and outcomes are measured.
• B. The time period during which a study collects all data.
• C. The period used to discount future costs.
• D. The window of the study's funding.

Answer: (A)

In economic evaluation, the time horizon is the duration over which costs and outcomes are measured. This matters because you need enough time to capture all relevant effects and costs of an intervention, including any long-term benefits or harms. The horizon should align with the clinical course of the condition and the perspective of the analysis; for chronic conditions with lasting effects, a lifetime horizon is often appropriate, while for short-term, acute situations a shorter horizon may suffice. It’s not simply the period over which data are collected, nor the window of the study’s funding. Discounting future costs and outcomes is a separate step that adjusts those values over the chosen horizon. Overall, the time horizon defines how long you track and value the consequences of the intervention.