Burndown charts offer tremendous insight into the likelihood of success of software releases and iterations. But are they enough by themselves?
For some teams, the answer may be yes, for others, the answer is not quite. To start, many agile teams marry velocity charts with burndown charts to also measure and report a team's rate of progress from iteration to iteration / which hopefully stabilizes over time. The velocity chart is a slightly more targeted view of the progress being made on a project as it relates to the delivery of customer/value features over time. These two charts combined offer tremendous visibility into overall project health.
To go one step further, we also track another set of metrics which help explain any variations or patterns within the burndown chart, because the burndown itself may not be enough to explain what is occurring. So in our project dashboard, we include metrics that help explain whether the scope/amount of work to be completed (for example, features at the project level and tasks at the iteration level) is also increasing or decreasing during the life of the project or iteration.
For example, if the burndown chart has flat/lined, a scope or task trend chart can help explain whether this is simply because the team is not progressing or instead that the team is progressing as usual, but functionality or new tasks are being added to the project at the same time. In this case, it is extremely valuable to know why the burndown chart is not burning down. As another example, if the burndown suddenly drops, a trend chart can help convey whether this resulted from a bunch of features being removed from the project or not.
Finally, for good measure, a complete dashboard should include a test metric to convey the number and corresponding status of acceptance tests within an iteration and/or project. Ron Jeffries' running tested features (RTF) metric is an example of this type of metric.
Using a comprehensive set of complementary metrics can provide valuable insight into project and/or iteration progress, as well as the potential areas that need attention.