Burn-up & Burn-down Charts
Key Words: Agile Project Management; Information Radiator; Transparency; Stakeholder Management; Release Management;
Introduction
These charts are widely used by scrum teams to track progress. They typically show progress within a sprint and are also often used to track towards a particular release over several sprints / iterations. Both charts are a visualisation of Work Completed versus a Desired Scope in order to help assess the likelihood of when a team will complete the work (or similarly, what work will be completed in a fixed timeframe). What originally differentiated these charts from traditional Project Management charts was the focus on 'work completed' and not work partially completed or effort expended. The work (backlog items) completed are, by definition, increments of value. Partially completed work has no value and is thus not counted. Furthermore, partially completed work requires an estimation of its completeness, adding to uncertainty.
The Y axis is some measure of the work to be done, often Story Points.
Product Managers tend to use these charts to not only track but also communicate the overall progress of the products that they're working on.
Each of these charts is used differently and serves a specific set of requirements. As such, they may both be used.
A Burn-down chart is used to learn about the work that is left to be done, while the Burn-up chart is used to show the work that has been already completed along with the total amount of work to be done. Or to put it another way, a Burn-up chart is often more useful when scope keeps changing and it is helpful to visualise it. It does NOT show why it is changing, and simply shows that it is changing. The reasons may be due to a general high VUCA situation, or it may be through intentional scope creep. Regardless of the reasons, it's useful to clearly communicate that there is risk and uncertainty around the scope.
Forecasting
One of the main benefits of counting only completed work (as opposed to counting work partially completed [WIP]) is that the projection will more accurately forecast when incomplete work will be completed. Note how it is good practice to show a range to the projection (the red and green dashed lines) based on the range in recent velocity.
There are various ways to forecast. In the example here, the scope line is also extrapolated in the direction that approximates the previous trend.
But is this the most likely scenario?
This next chart shows the scope being forecast to remain the same.
Of course, scope can decrease too because the scope measure is based on a set of estimates. As we progress, we are likely to learn more and requirements refined.
A final word...
for those interested in the psychology of agile and high performing teams. These charts trigger different emotional responses in the reader. We wont dive into the details here but you may consider how burning down to a fixed point increases a sense of control, ownership and accountability. Whereas a burn-up chart helps to emphasise where there is change and uncertainty. Whilst agile development was born from the need to manage and even embrace change, it also championed the idea of small batches... short timescales, iterative practices and delivering small product increments... as a means of managing change.
It's often useful to consider if a Burn-down chart can be used and if it can't (or doesn't feel the most appropriate), think about tackling the reasons why.