Let’s say that a relatively new team has been working hard but unable to complete all the tasks that they committed to for the current sprint for a number of reasons. The current sprint was scheduled for 4 weeks.
Would it be a good idea to extend the sprint by 1 week to finish the unfinished work? Why or why not? What are some of the pros and cons of extending?
No, it is not a good idea to extend the sprint by 1 week to finish the unfinished work.
One of the most important concepts in Scrum is the concept of “fixed time variable scope”. You “fix” the timebox (sprint) that the team has to work in, and you let the output of the team determine what fits into that timebox. When you see the performance of the team for a given timebox, that helps you to be able to understand (and forecast) what the team can get done over multiple timeboxes.
If you constantly vary the lengths of the sprints, you have no “measuring stick” by which to judge how much work the team can get done over N number of sprints. In other words, your velocity measurements will be useless without a constant time box. Imagine if the inches on a ruler were different sizes. How could you measure anything?
Also, by extending the sprint you rob the team of the opportunity to get a true understanding of their own capacity and thus, ability to estimate. This a critical part of the feedback loop that helps the team get better.
Lastly, extending the sprint will most likely hide the real problem that you most likely need to solve for. Did the team bite off more than it could chew? Was there an external dependency that was not managed? Was there an impediment that prevented the team from finishing? Extending the sprint papers over what might be a learning opportunity for the team.