Burn down chart
A burn-down chart is a graphic representation of the remaining effort in a project in relation to the remaining time. The work still to be done ("backlog") is usually shown on the vertical axis and the time on the horizontal axis. It is therefore a line diagram of the effort to be made. Such a graph is used to predict when the job will be completely done, or if it will be when it is scheduled. It is often used in agile software development methods such as Scrum . However, burn-down charts can be used for all projects for which project progress can be measured over time.
In addition to or instead of the time, milestones can also be indicated on the horizontal axis.
Interpretation of burn-down charts
The burn-down chart shown here shows a project or a completed iteration. The following can be read in detail:
| X axis | Temporal course |
| Y axis | Remaining effort in the project, either the estimated remaining effort (time, story points) or the actual remaining effort (number of unfinished tasks). |
| Project starting point | Left-most point on the chart that appears on day 0 of the project. |
| Project endpoint | Rightmost point in the diagram that marks the end of the project. Its distance from the starting point results from the total project effort divided by the daily affordable amount of project work. |
| Ideal tasks remaining | A straight line from start to end. At the starting point, the ideal line shows the estimated total project effort. At the end point, it meets the X-axis, because then there is no effort left. Although the line is called "ideal", it does not have to be right in the specific project to follow it as closely as possible over the entire course of time. Rather, the line represents the idealized assumption that the effort in the project would be done evenly over time. Nevertheless, the ideal line helps to assess the progress of the project, and towards the end of the project the ideal line must be hit again in order to complete the project on time. |
| Actual tasks remaining | This line shows the actual remaining effort. At the beginning and, if the end date is met, also at the end, this line is level with the ideal line. In the course of the project, the line will move more or less far from the ideal line and show how efficiently the team worked on the project. At the end of a working day, a new point arises, in which the work done on this day is deducted from the previous remaining effort. |
Interpretation and efficiency measurement
| Actual Tasks Remaining is above Ideal Tasks Remaining | In this case, there is more work to be done than planned, so that the project is behind schedule. |
| Actual Tasks Remaining is below Ideal Tasks Remaining | In this case, there is less work to be done than planned, so the project is ahead of schedule. |
There is more information that can be read off such a chart.
The chart is an instrument for recognizing deviations and being able to react to them. If a project is ahead of or behind schedule, this does not have to be due to particularly good or poor productivity of the team at times, which could perhaps be corrected without special measures. It is also possible that the effort estimate was too imprecise, or the scope of the project has changed. These effects can be taken into account by changing the team, but also by changing the schedule (adjusting the project end point). It depends on the methodology used and the specific project situation, which deviations can occur and how they are reacted to.
Eliminate inaccuracies in effort estimates
In burn-down charts, the correspondence between the actual and ideal lines also depends on how precisely the effort was estimated. If a team tends to overestimate the effort, the progress line will always be below the ideal line and also hit the X-axis prematurely, so that the project will be completed earlier than planned. The opposite effect occurs if the effort is underestimated and the team is late. To correct this, an efficiency factor is introduced by which the estimated effort is multiplied before the ideal line is drawn. This factor results from the ratio of estimated and actual effort in the past. Some templates for creating burn-down charts show the respective efficiency factor, so that incorrect assessments can be more easily noticed, measured and taken into account in the future.
Criticism and modifications
The burn-down diagram is based on a situation in which a team dedicates itself to the project under consideration with the same use of resources over the entire duration. It's not always realistic. If resources (e.g. experts) are not fully available for a project, the diagram can be modified so that the ideal line deviates from the straight line. In times when fewer resources are available, less processing should be provided, and vice versa. To test the correct application of this consideration, the ideal lines of all projects can be superimposed. If necessary, a pseudo-project can be created for vacation and other times when employees are absent for project work. The sum (stacking) of all ideal lines must again result in a linear course at the end.
Individual evidence
- ↑ Feel The Burn, Getting the Most out of Burn Charts . July – August 2009.
- ↑ Agile Burn Chart - Release Burndown Charts .
- ↑ Feel The Burn, Getting the Most out of Burn Charts . July – August 2009.
- ↑ Burn Down Chart Tutorial: Simple Agile Project Tracking . December 2010. Archived from the original on July 7, 2013. Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved September 30, 2015.
