Burndown chart helps teams understand the amount of work that has been completed and the remaining work in a sprint. It also helps you understand how much ad-hoc work has been pulled into a sprint after starting it.
Insights that you can derive from the burndown chart
1. A spike in the number of tasks in the middle of a sprint relates to the amount of ad-hoc work that is being pulled in.
2. During the sprint, if there's a spike in story points without any ad-hoc tasks, then it shows that tasks are being re-estimated. This signifies that your team needs to get better at estimates during planning.
3. If your team is consistently finishing tasks much earlier than anticipated, it could be an early that your team is under committing and there's room for more tasks.
Ideal line vs Actual line
The idea line (grey) represents a linear burndown of tasks/story points in the sprint and if the actual line (green) is mostly below ideal, then it indicates that chances of completing all tasks in the sprint is more.
Burndown charts is now live for everyone. You can access it by opening the "Sprint Insights" or "Insights" module.
We use the burndown chart on a daily basis to determine the progress of work being completed.
Most if not all of our tasks contain sub-tasks with work items that needs to be tracked. The burndown chart only decreases on the completion of a task, not sub-tasks, which gives it the look of a waterfall approach. Our task can only be completed when all sub-tasks are done, so the graph is a flat line until the last day of the sprint when we complete the final sub-task and then the task.
Using the current model, we can not determine if we are on track to deliver the required work by the end of the sprint.
Do any other users of the system follow the same process as us? Do you need to track sub-tasks? These will influence the completion of the task, and we need advance indication of this, by tracking sub-tasks.