Why are data sources important in economic evaluations?

• A. They provide the costs, effectiveness, and utilities; their quality affects results and uncertainty.
• B. They are optional and rarely influence results.
• C. They only determine the sample size.
• D. They provide the budget forecast only.

Answer: (D)

Data sources are the backbone of economic evaluations because they provide the actual numbers for costs, health outcomes, and patient utilities that feed the model. The quality and relevance of these sources shape how accurate the estimated values are and how much uncertainty surrounds the results. Relying on a budget forecast alone misses the full picture: it doesn't capture the real-world effectiveness or the value patients place on outcomes, and it may overlook bias or variation in costs and effects. In practice, analysts pull from trials, observational studies, administrative data, and published literature to estimate resource use, unit costs, effectiveness, and utilities. These inputs also influence the study perspective, time horizon, and how generalizable the findings are. Because inputs can vary across sources, sensitivity analyses become essential to show how conclusions might change with different data choices, helping decision makers judge robustness and applicability.