PlaybookPrompts

Stress-test the assumptions behind a numeric forecast

Data & Analysis forecastingrisk-analysisfinance

Most forecasts fail not because the math is wrong but because one or two key assumptions are never questioned. This prompt systematically surfaces those assumptions and shows what happens when they break.

Prompt
You are a senior financial or data analyst. I have built a forecast and need to stress-test its underlying assumptions before presenting it to leadership.

Forecast description (what is being forecast, over what period): {{FORECAST_DESCRIPTION}}
Key inputs and assumptions (list the variables and values you used): {{ASSUMPTIONS}}
Forecast output (the headline number or range): {{FORECAST_OUTPUT}}
Consequences if the forecast is materially wrong: {{STAKES}}

Follow these steps:
1. Review my listed assumptions and identify which three are most likely to be wrong or most sensitive to small changes. Rank them by impact.
2. For each of the top three assumptions, define a pessimistic case (realistic downside, not worst-imaginable) and an optimistic case. Use specific numbers, not just 'higher' or 'lower.'
3. Calculate or estimate the revised forecast output under each scenario. If I have not given you enough information to calculate exactly, show the formula and flag the missing input.
4. Identify one assumption I did not list that is implicitly baked into the forecast and could meaningfully affect the result.
5. Write a two-sentence risk disclosure I can include in the forecast presentation that honestly conveys the range of outcomes without undermining confidence in the central estimate.

Note: This prompt is most useful for forecasts with 3–15 explicit inputs. If your model has dozens of variables, prioritize by running a sensitivity analysis first to identify which inputs drive the most variance.
Variables to fill in
  • {{FORECAST_DESCRIPTION}}
  • {{ASSUMPTIONS}}
  • {{FORECAST_OUTPUT}}
  • {{STAKES}}

How to use this prompt

  1. Copy the prompt above (Copy button on the top-right).
  2. Replace each {{VAR}} with your own value. Variables: {{FORECAST_DESCRIPTION}}{{ASSUMPTIONS}}{{FORECAST_OUTPUT}}{{STAKES}}.
  3. Paste it into one of the recommended tools below.
  4. Iterate: tighten constraints in the prompt if the output is generic.

Why this prompt is structured this way

The prompt is split into explicit steps because LLMs do better when the path is named, not implied. Each variable forces specificity at the input layer — vague inputs get vague outputs.

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