Scrum – How to Re-estimate Stories in Scrum

estimationscrum

Every day, after the stand-up, my team and I update our estimates for each story. I have a feeling that there is something wrong with the way we do it, so I need your help.

This is how we do:

Story A estimate: 24 hours (8 hours per day – we use "ideal days" as the measure)

  • Day N: developer starts working on Story A in the morning (8 hours of work completed by the end of the day)
  • Day N+1: Story A re-estimation = 16 hours (one workday taken out of Story A, from day N)
  • Day N+2: Story A re-estimation = 8 hours (one workday taken out of Story A, from day N+1)
  • Day N+3: Story A should be done by now. But it's not. The developer reckons it
    will take another 3 hours to finish. We update the story on the whiteboard
    and burndown accordingly.
  • Day N+4: Story A took the whole day to be finished instead of only 3 hours! Now it's done. The difference, 5 hours, is completely unaccounted for in our planning.

How should we be daily re-estimating our stories?

Best Answer

The difference, 5h, is completely unaccounted for in our planning.

Yes, it is accounted for implicitely because the following tasks are delayed. If there was a burndown chart just for that developer, you'd notice that the curve has remained "flat" for one day while it would have gone down if the developer had finished it early enough to take on another task.

There's nothing wrong with the way you're re-estimating during daily meeting, re-estimation is more about figuring out if we can make it for the end of the sprint than it is about tracking the exact lateness of each task. All you need in Scrum to be able to adjust your plan on a daily basis is something that indicates Sprint progress and how far you are from meeting the Sprint goal (typically, a burndown chart).