Scope, time and cost

Every project has three constrained quantities: what is being built, when it must be done, and what it may cost. Quality sits inside them, and when the three are fixed it is quality that quietly gives way.

The useful rule is that you cannot fix all three. If scope grows and the date does not move and nobody is added, something is going to be worse than it should be, and usually nobody announces that. It appears as bugs, missing documentation and a team that stops caring.

So the first question on any project is which of the three can move, and the second is who is allowed to decide. Get those answered before you start rather than during the crisis, and write the answers down.

Three common shapes. A fixed date with flexible scope, such as a trade fair or a term start, where the useful question is what must be ready on the day. A fixed scope with a flexible date, such as a regulatory requirement. And a fixed budget, where you decide what fits.

Say it out loud when a change arrives. "We can add that. It moves the date by two weeks, or we drop the reporting module. Which would you prefer?" This is the single most useful sentence in project management. It is not obstruction, it is a decision handed to the person entitled to make it, and it converts an argument into a choice.

Write down the trade offs you were given, with dates. When somebody later asks why the reporting module is missing, the record is the answer.