Conventional software project management uses Gantt Chart to plan task activities and estimate how long it will take to complete a project. However, it is hard to maintain and overshadow the the big picture with details. The most 2 important things to know in developing a project are
- Are we on time?
- Are we on budget?
By using the burn down chart or budget chart, we will get a clearer picture on our current project state. From there, we can estimate the works to be completed with reasonable budget. Look at the example below:
The dotted gray line is the target. In this example, the project is 10 weeks long. Each week, we expect to complete 10% of work and use up 10 % of budget.
That's the ideal scenario and of course real worls is different. That's why we need another 2 lines.
- The orange line shows how much budget has been "burned". It is based on actual hours worked by the team. in this example, we are 3 weeks into the project and we've burned 40% of the budget.
- The green line shows percent complete. It is based on features-completed so far. In this example only 20% of work completed at the end of week3.
The project is in trouble. We've spent 40% of the budget to complete only 20% of work. According to plan, we should have use 30% of budget to complete 30% of work. At least, we noticed the bad progressing early and we still have times to fix it.