When starting a project we always make a good estimate of all known requirements, and plan budgets and available developers accordingly.
Requirements change. Budgets usually don't.
To make sure a project stays on track, we update our estimates once a month and compare them to the remaining budget. If this doesn't match any more, we have to act.
To update an estimate, do the following:
- Start with the most recent estimate for the project.
- Which stories have been completed? Set their estimate to zero.
- Have any requirements changed future requirements? Adjust them.
- Have you become aware of new requirements? Add them.
- Have you become aware of any bias in our previous estimate?
Did we grossly over- or underestimate certain aspects of the project?
Do you have to correct further estimates accordingly?
- Our estimates always include a percentage markup for organization and project management anywhere between 10% and 30%.
Is this value still correct? If not, adjust it.