Project Management Triangle

The project management triangle, sometimes known as the iron triangle, is a concept in project management circles that defines the tradeoff between schedule, budget, and features, often summed up as "fast, cheap, good: pick two."

The concept explains how project speed, project price, and project quality are linked in a way that you cannot change one without affecting the others. For example, asking for a project faster means it will either cost more money or it will include fewer features or lower quality. 

This concept comes up when explaining the value of a project, forcing project leaders to determine which corner they're willing to give on. Pretending you can max out all three is how projects end up late, over budget, and half-built.