Meet These Preconditions Before You Think about Project Estimations
What do you do when a manager asks you for an estimate about a project's release or budget? What you should be doing is responding with a question: What’s most important to you?
You can have only one number-one priority in any given project or program. You might have a number-two priority right behind it and a number-three priority right behind that, but you need to know where your degrees of freedom are.
Your manager can choose to rank the feature set first, or time to release, or cost, or a low number of defects, etc. It doesn't really matter what is determined to be the most important focus, so long as you know what it is and you only have a single number-one priority.
If management has not thought about the constraints, they may be asking employees to cram in too many features with insufficient time, given the requested date to release, low number of defects, and expected cost.
The time to release is dependent on the number of people, their capabilities, and the project environment. You can make anything work, but it won't have the results you wanted. This is why estimation of the budget or the time to release is so difficult.
If you really want to estimate a date or a budget, you need to have these preconditions:
- You must have a ranked backlog. You don’t need a final backlog, and you can certainly accommodate a changing backlog, but you need a ranked backlog. This way, if the backlog changes, you know you and your team are working on the priorities in the correct order.
- The team who will do the work is the team who is doing all the estimation. Only the team who is doing the work can estimate the work. Otherwise, the estimate is not useful. Surrogate estimators are biased estimators.
- You will iterate on the release date and on the budget. Train your managers to expect that from you.
- All estimates will be reported within a confidence range. If you report estimates as a single point in time, people think your estimates are precise. If you report them as a confidence range, people realize how inaccurate and imprecise your estimates are. And that brings us to number 5:
- If you can say this without sounding patronizing, practice saying, “Remember, the definition of an estimate is a guess.”
Once you’ve met the preconditions, you can estimate more accurately.