Estimating the Unknown

A great article on Product Management, called "Estimating the Unknown" by johanna

Almost every manager I know wants to know when a project will be done. Some managers decree when a project will be done. Some managers think they can decree both the date and the feature set. There is one other tiny small subset, those managers who ask, “When can you finish this set of ranked features?”

Read more starting at http://www.jrothman.com/blog/mpd/2011/11/estimating-the-unknown-dates-or-budgets-part-1.html

The article at http://manage.techwell.com/articles/weekly/software-project-estimation is also very good, as it details how to use confidence levels to provide more accurate estimates

A Scrum team was struggling with their estimation process. They'd tried different techniques, including using story points instead of time blocks, but in the end, a senior manager would get a date in mind and the estimates would have to be massaged to meet that date. The fact that they never met that date was a cause for concern.

To combat the confusion, I proposed a new methodology. I would use an estimate-uncertainty factor and Monte Carlo simulations (statistical methods of generating possible future outcomes, used in scientific studies and other fields [3]) to come up with a target release date range which we would present to management for further discussion. Each item in the estimate date range would have an associated probability of completion attached to it. Early items start out with a zero percent probability, and dates further in the future start to move slowly towards a one hundred percent probability.

This example uses the Galton tool at http://estimate.bz to prepare estimates. I think I will use this for my next estimating process.