What outputs are produced by probabilistic sensitivity analysis (PSA)?

• A. A distribution of incremental costs and effects, often presented as ICER scatter plots and CEACs.
• B. Only point estimates of costs.
• C. Only total budgets.
• D. Unexpected model outputs.

Answer: (A)

Probabilistic sensitivity analysis conveys uncertainty by treating model inputs as distributions and running the model many times. The outputs are therefore distributions of the incremental costs and incremental effects, not a single number. These results are typically shown as an ICER scatter plot in the cost-effectiveness plane, where each point represents one simulation’s combination of incremental cost and incremental effect. This visualization reveals how often an intervention is more effective for an added cost, and in which regions of the plane the results cluster.

To summarize how likely an intervention is to be cost-effective at different values people are willing to pay for an extra unit of effect, a cost-effectiveness acceptability curve is produced. The curve plots the probability that the intervention is cost-effective across a range of willingness-to-pay thresholds. This combination of scatter plots and acceptability curves is what PSA provides, giving a probabilistic view of value under uncertainty.

These outputs emphasize uncertainty and decision context rather than offering only point estimates, total budgets, or undefined “unexpected” results.