How to determine Project Health with Burn Down Chart? Let suppose that the Project consists of 18 User Stories and 3 Iterations were finished. We would like to estimate the date when the Project will be finished.
Let look the picture bellow. At beginning of the project we have sorted all User Stories by Risk and Business value. We have started from the most risky tasks. That is why only 4 of them were made at first 2 iterations. As we see, the team’s productivity increasing from previous iteration to next.
At the first look to receive correct finishing date of the project it is enough to approximate last iteration productivity until it crosses the time axis. We assuming, that our team will work at least with the same productivity or even better. There are good reasons for our assumption: inter-team organization and understanding of the project have increased, complexity of User Stories have decreased. This can be true for ideal project. However in real project Burn Down Chart will look mostly like below.
What has happened? We have just forgotten about integration and bug fixing. The count of bugs and integration time are increasing with the increasing of completed User Stories number. That is why the time left to make new features was decreased.