Once you’ve added your historical data and found the epics or versions to forecast against, now you need to choose a forecast certainty in the Forecast Parameters box.
A forecast certainty is a reflection of your ability to absorb risk in your forecast. The Monte Carlo Simulations that we use to forecast run thousands of simulated trials using the data you configured in the Portfolio Forecaster.
This allows us to see all possible completion dates and how often each completion date happened. This allows us to make a probabilistic forecast containing a probability (85%) and a range (by the forecasted date or earlier).
A probabilistic forecast: There is an 85% chance that Item X will finish on or before Y date.
This means there’s a 15% chance it won’t. You adjust the forecast certainty according to the risk you’re willing to take.
Please note two things:
We can never be 100% certain. The only things we can be 100% certain about are the things that already happen.
The higher you make your certainty, the more padding your forecasts will have for many items because it is accounting for more less likely possibilities. So, if you go too high you might as well just look at how long it took to do the longest-running item as use that as a forecast for any given epic.