Agile and Budgeting

Scott Ambler has an excellent discussion of the relationship between, resources, and schedule in the "Iron Triangle" of software development and the need for flexibility in at least one of these areas to ensure project success. Scott concludes by outlining several scenarios in which one or more of the sides of the triangle can vary.

In my experience, the budget for a project is usually fixed, or at least proscribed to a certain upper boundary. So there are really only two sides of the triangle that can vary -- the scope and the schedule. Of these two, I find that the schedule is usually less flexible that the scope -- often there is a market-driven date establishing an outer boundary on the development process.

Which leaves us with the scope of the project as the only negotiable or variable side of the triangle. This leaves the development manager in a somewhat difficult position -- how to satisfy the user community (who's focus is on features) and also the client bursar (who's focus is on budget and schedule). The key to this is to develop the most important features first and leave the less important features for the end of development. This, in turn, requires a frank and realistic discussion of feature priorities. So, at the outset of a project, perhaps the most important thing the development manager can do is to get a solid list of the features and their priority.