Burn Down Charts

Why the Burn Down?

How important is status? In a high-paced environment status is very important. One way of reporting status is a burn down chart. A burn down chart is a graphical representation of work remaining versus time. On the vertical axis you will find units (hours) of work remaining. On the horizontal axis, you will find time. Figure 1 illustrates a simple burn down chart.

Figure 1: Simple Burn Down Chart

In this burn down chart, the units of work remaining are 7200. At this constant rate, this project should be completed in 31 days. The burn down chart is a much more accurate depiction of overall status than a somewhat educated guess. For example, if a sprint has 10 tasks and 8 of those tasks are completed. One may be tempted to report their status as 80% complete. This would not be the case, if the last two tasks take longer to complete than the first 8 combined. In this case, a burn down chart would be very valuable because the tasks would be measured in hours, therefore the estimated completion would be more accurate.

How do we burn it down?

Now, that we understand the importance of burn down charts. How do we get started? The first determination that must be made is how many hours will be needed to complete this sprint, iteration, or project. In many organizations, each team member is asked to estimate the number of hours it will take to complete each of their tasks for that sprint. We also need to know our deadline. With this information, we can determine what needs to be done to meet this deadline or even if the deadline can be met with the given scope and resources. This brings us to how burn down charts aid in planning.

We don’t plan the burn, the burn plans us!

As the work is completed, a comparison can be made between the estimates and the actual work, as seen in Figure 2. The burn down chart should be seen as a living graph. It can be updated throughout the project. As you can see, on the fourth day of this sprint we experienced a significant growth in scope. This information can be used to plan ahead. Should we plan to work overtime to complete this project by the scheduled deadline? Are there items that can be de-scoped from this sprint to ensure that we meet our scheduled deadline? Should the deadline be extended so that all functionality can be included?

Figure 2: Burn Down Chart with Planned and Actual Work Remaining

Instead of Burning it down, why don’t we Burn it up?

Using a burn down chart is not the only way. Many people prefer burn up charts. The burn up chart’s advantage is more information can be communicated. In Lee Richardsons blog, “Forget Burndown use Burnup Charts, he explains that in a burn up chart how much work was actually completed during a sprint can be shown as opposed to how much work remains. Also, he explains that a burn up chart can demonstrate more clearly how much total work the project contains. Figure 3 shows a burn down and a burn up chart that Lee Richardson uses to demonstrate this point of view. In the burn down chart, it appears not much progress was made in Iteration 6. In the burn up chart for the same project we see that there was a growth in scope by 20 units in iteration 6. The burn up chart more clearly explains that it isn’t true that progress wasn’t made, that in fact there was growth in scope.

Figure 3: Lee Richardson’s Burdown and Burnup Charts

Although, I will agree that the burn up chart has its advantages, I feel the burn down chart has its advantages as well. The burn down chart is a more simplified chart and is much easier to understand, and therefore more appropriate for communicating frequent status to a large audience.

Conclusion

The burn down chart is a great tool for predicting when a project will be complete. I believe Alistair Cockburn said it best. “The burn down chart illustrates the three following points: What is done?, What is left?, and How are we doing?” (2) I believe a great advantage to using either burn chart is that they allow for continuous improvements. Issues can be detected virtually as soon as they arise. If you have a growth in scope or are lacking progress for some reason, it will show on your chart and you will have the ability to plan accordingly. The last thing you would want to happen is to arrive at the last day of the project and realize the deadline will not be met.

By: Janie

References

1. “Forget Burndown use Burnup Charts”, Lee Richardson, http://www.nearinfinity.com/blogs/lee_richardson/forget_burndown_use_burnup_charts.html
2. “Earned Value and Burn Charts”, Alistair Cockburn, http://alistair.cockburn.us/Earned-value+and+burn+charts
3. “Burn Your Burn-down Charts”, Jurgen Appelo, http://agilesoftwaredevelopment.com/blog/jurgenappelo/burn-your-burndown-charts

Advertisement