While the Process Control Chart quickly spots the entities that took too long to get done, the Lead and Cycle Time Distribution chart helps you make realistic forecasts.
To access this chart, please navigate main (top) menu -> Reports -> Cycle Time Distribution.
You can filter out any entities, just as in the Process Control Chart:
That's how you build this chart for the 3 pts user stories done within the last 180 days. As you can see, there's a 38% probability for such user stories to be completed in 8 days:
How would the forecast look for 1 pt user stories? There we go: it's 94% for 8 days. The difference is huge.
Here's a real-life case. Imagine, you have a deadline. 12 days before a release. You are the Product Owner, and you're talking to your team: “I've promised one important user story to a customer. Can we make it in this release?” The team give their estimate, it’s 3 pts in their opinion. You open the Cycle Time Distribution chart and say: “Well, the probability to complete such a story in 12 days is 45%, so it's unlikely that we deliver on time”.
This conversation is intelligent as it's based on facts and statistics. It’s not a finger-in-the-air estimate. The Product Owner may decide to split the user story, and fit a smaller one to the release out of realistic expectations, as a compromise.