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?