Sprint burndown charts are used to track progress in sprints. They are an easy way for teams and Scrum Masters to see at-a-glance how work is going during a sprint. Burndown charts are also a helpful tool for Scrum Masters to use when looking for team patterns and opportunities for improvement. To understand how turndown charts work, it's helpful to walk through a few sample turndown charts.
Sprint Burndown: Scrum Team Struggling to Finish
We can see in this example there are several risks. First, notice that pending work (highlighted in grey) is increasing around the middle of the sprint. This means that the team is either taking on new work or the work they have in place was not estimated/decomposed very well. Second, notice that the work in progress, highlighted in yellow, is increasing almost to the last day of the sprint. This means that the team is taking on more work than they are finishing. Last note that although the team originally committed to nearly 300 hours of work, they only finished half that (the green area on the chart). A good ScrumMaster will help the team see these issues and get them fixed so the team can get on its way to being high performing.
Let's look at another.
Sprint Burndown: Scrum Team Performing Well
in this burndown, things are better. The pending work stays relatively flat, the work in progress is small, indicating there was thought put into place on the tasks needed to accomplish the stories, and the task sizes are small. Last we can see the team finished their work. These are typical results after two to three months of a team being together.