Wednesday, June 10, 2009

Good Enough Metrics...

Another post triggered by my interaction with other customers using VersionOne. We were discussing story points, velocity, capacity, and other metrics. Here's what Tom said when he was trying to figure out team capacity each sprint:
As an example some of our teams state the base capacity of every team member (assuming a 2 week sprint) is 10 days * 6 hours a day. The 6 hours rather than 8 is to account for emails, minor interrupts like unplanned meetings etc. Then they reduce capacity based on company mandated holidays (we are global so ever office is different), then they reduce hours for the sprint meetings. this becomes the max anyone on a team can contribute to a sprint. The team members may additionally subtract off vacation time, or other meetings they are required to attend, trainings, etc. it would be nice if a team can define a default formula based on known factors, and team memebrs have an additional ability to have thier own formula that can further adjust thier own availabilites beyond that, or even just override it with a typed in value.
Wow! This sounds like a lot of work! Does this additional planning accuracy actually provide a similar level of accuracy predicting the outcome? I'm guessing it doesn't. When we transition to agile, over time we slowly learn to trust what our agile coaches / education told us up front. Here was my response:
This is great and I remember going through this myself. I had excel spreadsheets in the back of my sprint backlog where I could enter holiday and other data to get this value.

What we found over time was that it became somewhat unnecessary as your velocity and team matures. We slowly transitioned to story points and relying on them to do sprint planning. We picked our stories and blew out the tasks for them only when the story was picked up (mid-sprint we swarmed on open stories and closed them every day instead of running them all in parallel). We did just in time task planning and estimation (more efficient).

This led to us no longer needing all those calculations. Holidays and vacations were a simple head calculation (example: typically we do 20pts per 10 day sprint with 10 people = ~.2pts/person/day, we have 5 people taking 1 day of vacation = ~1pt... so plan 19 pts this sprint.)

It's an interesting problem to solve in the short term, but I'm guessing every team will have a slightly unique view on the calculation... and I'm guessing most people will outgrow this need over 6 months to 1 year.
I'm a strong believer that conversations of planning and capacity should focus on days and story points, not hours and tasks. Without getting into the debate that estimation isn't needed at all (that's another discussion), what are your thoughts?

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