Architecture & practice·Estimation and planning
the date was fixed and the scope was fixed, and everyone acted surprised about quality.
Iron triangle
Also calledproject management triangle, scope cost time
Scope, time and cost are related, so fixing all three fixes quality as the thing that gives. It is a crude model and it remains the fastest way to have an honest conversation with a stakeholder who wants all three. The engineering contribution is to name which variable is actually moving, because when nobody names it the answer defaults to quality and nobody has to admit it.