The Importance of Time-boxing

When using Scrum, your iterations are fixed time (1 week, 2 weeks, 30 days etc) and therefore your cost is fixed so the only thing that can vary is scope.  Time-boxing is critical to success when implementing Scrum since you don’t really want to waste a lot of time in useless or long discussions.  Yesterday I posted about an estimation session that went off the rails pretty quickly and it was due to the fact we (well, “I”) dropped the ball on enforcing the time-box rule.  We started strong and finished weak.  A stop-watch, wall clock, phone/pda or whatever is fine to use.  I like to use this online tool.  You can set the timer for whatever interval you want and it’ll beep when your time is up.  I typically give warnings at 5 minutes to go and 2 minutes to wrap it up.

Our iterations are 1 week (we’re re-implementing Scrum, so the shorter the better to allow the problems to surface quickly) so we use these guidelines for time-boxing:

  • sprint backlog: 1.5 hours – this is where the team commits to their work and break stories into tasks.
  • development activities1 hour –  If you’re stuck after an hour, ask a team member
  • ‘stop the line’ discussions:  15 minutes -if a team members runs into a roadblock, the whole team stops and a quick 15 minute brainstorm session happens.  All potential solutions are written on the whiteboard and then the line resumes work.

The biggest question the team always has around time-boxing is “what happens if the meeting is over and we haven’t finished our task breakout?”  The answer is simple:  The meeting is over.  If you didn’t meet your goal, schedule another discussion or in this case, when it comes time to work on that story, time-box the task breakout to 15 minutes.

The lesson is, by time-boxing your efforts you force yourself into focusing on the issue or discussion at hand.  It’s tempting to allow a couple more minutes here and a couple more minutes there, but avoid the temptation.  The team will get into a rhythm pretty quickly and be much more efficient at time-boxing.