Friday, November 25, 2005

Review: Agile Estimating and Planning by Mike Cohn

Just wrapped up reading this one on my flight from IAD to SFO: Agile Estimating and Planning, by Mike Cohn. It has some very practical direction on how to put agile planning practices in place. I think a lot of people need materials that are pretty detailed. I agree with the principle that methodologies should be adapted to fit the needs of the teams, but having all of the options laid out makes that a multiple choice decision, rather than a free response.

I faced the very trials that he described when attempting to figure out how to put story points or ideal days in place for size estimates. Ideal days do make that initial hump of estimating easier- they give people a frame of reference. Once we did that a couple of times though, I just switched to a couple of size measures (Extra Small (0), Small (1), Medium (3), Large (5), Extra Large (10)) and everything bigger than 10 ideal days had to be split into smaller tasks. At that point, the numbers were just relative sizes, and we could call them points without anyone thinking we weren't being serious.

The one place that I thought the book fell down was the one thing I was really looking for advice on, how to transition from that list of things that you are about to tackle in an iteration to the particular assignments that have to get handed to developers. Mike recommended doing some detailed estimates at that point, down to the hour level. I have to say I am closer David Anderson's approach on that point. Don't estimate at that level. However, I think David's all or nothing approach of doing no estimating is really only appropriate for Feature Driven Development, where all of the features are roughly equal. With the approach we usually take, bug fixes and everything else have to get factored in there, and there can easily be order of magnitude differences between the amount of work for each work item/task. However, coming up with the size estimates is pretty easy when there are only 5 choices.

So, Mike's book is good- far more practical than most of the other agile management books that seem to be coming out of the woodwork... You should check it out. The price jumped up pretty high on Amazon, but it's worth it.