We continue what has become a week focused on the conversations which happen around a simulation with a discussion of how to collect multi-point estimates.
It doesn't take much searching to turn up 100's of blog posts, presentations and journal articles on the best way to create three-point estimates. However, many times when creating a simulation, asking experts is the only option available.
Uncertainty vs. Risk
"If our partner doesn't come through, which is the worst case, it will cost us $1.5 million."
The range of the estimate should be about the uncertainty of a situation, not the individual risks. Particularly with worst-case scenarios, people have a tendency to start lumping in "what-if" cases. As the manager, don't dismiss those concerns, but capture them as risks rather than including in the range of the estimate.
Remember - there can be risks that improve the outcome - be sure to capture those as well.
Unrealistic Extremes
"Best case, we can get it done in an hour, worst case, 10 years."
Particularly for people new to estimating, there is a tendency to go crazy with the extremes. On the flip side, people can appear overly certain about a particular outcome. Both cases require you to help guide the conversation - some key questions can help -
- Can you imagine how this could cost twice/half what you think?
- What are the conditions that could lead to the extreme scenario you're describing?
- What additional information could help reduce your uncertainty?
Build Trust
The worst thing a manager can do is collect estimates then turn around and commit a team to hitting the best-case. A lot of times, the unwillingness of team members to enthusiastically engage with the estimation process stems from being burned in the past.
To get good estimates, you need to prove you'll use them appropriately, making the experts partners in the estimation process.
Final Thoughts
We've only scratched the surface here, providing a few ideas to keep in mind. Estimating is a skill and as a manager it is important to help experts through the process and help build their estimation ability.
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