Comparison
Parkinson's lawvsTimebox
Parkinson's law
the task had two weeks allocated and took two weeks, and it would have taken three days in a crisis.
Work expands to fill the time available for its completion. It is the counterweight to padding: generous estimates do not usually finish early, they finish on time with more gold plating and more deliberation. It is an argument for timeboxes and small batches rather than for squeezing people, which produces the same expansion with worse quality and less trust.
Full entry →Timebox
you agreed to spend two days on it and to come back with what you had, whatever that was.
Fixing the time and letting the scope or the outcome vary. It is the standard control for open-ended work — investigations, spikes, debugging, proofs of concept — because such work has no natural end and will absorb whatever it is given. The discipline is the ending: a timebox that is silently extended twice was never a timebox, it was a wish.
Full entry →