Sensitivity analysis

Changing one assumption at a time to see how much the answer moves. It converts a single number into a map of what the number depends on.

The usual presentation is a two-way table with the discount rate on one axis and the terminal growth rate on the other, showing the resulting value in each cell.

The reason to build one is not to widen the range but to find which two assumptions matter. Most models have exactly two, and the rest of the spreadsheet is precision applied to inputs that barely move the answer.

Once you know which two, the research plan writes itself.