A member of a new agile team asked the Scrum Development list how to keep track of the actual time engineers spend on tasks, and how this relates to the agile concept of velocity. Velocity is the agile metric for tracking how fast the team is completing features, and thus how long it will take to complete a project. The group’s opinion was that tracking time spent isn’t necessary or useful.
I’m currently working with a client that is struggling with this same issue. After reading some books, they started down the path of estimating stories using points, but then breaking them down into tasks that are estimated in hours. They then wanted to use burndown charts, but became confused about whether they should burn hours or points. They also weren’t sure if they should have a single burndown for the whole release, of a series of burndown charts, one for each sprint.
My advice is to only estimate, track, and chart stories. Completed stories are the unit of delivered value, and the only thing that people outside of the team care about. If the team’s stories seem too big for this to be workable, the solution is smaller stories, not another level of tracking overhead.
Most folks on the Scrum Development list, including Ron Jeffries and George Dinwiddie, seem to agree with this approach. It was a good discussion thread and I recommend reading it. You might also want to read the article I wrote for InfoQ about the discussion, or this one about Ron Jeffries’ thoughts on burning stories not tasks.