Working with Project Constraints - The PM Triangle

Veteran project managers like to share a classic inside joke about what happens when someone requests a new project:

“We can make it good, fast, or cheap. Pick two.”

Scope, Time, and Cost make up the three corners of the triangle that project management professionals refer to as “project constraints.” In an equilateral triangle, all three corners are equal, and projects come in on time and on budget, while addressing all of the needs originally expressed by project stakeholders. However, if just one of the corners starts to fall out of line with expectations, the entire project can become distorted.

Some project management professionals use the project constraints triangle in a different way. Keeping all three of the angles representing project constraints at a consistent sixty degrees, managers using the plotting method map the triangle to an X-Y axis. Using this kind of diagram represents projects that do not change in size, but still undergo changes in scope, time, or cost.

Plotting project constraints can illustrate quickly to managers how “small” changes in budgets or timelines can impact the overall quality of a team’s work. In the example below, a project suffers from "feature creep," causing distortion of the project's scope. If project leaders fail to account for the increased costs of the project, it will simply take team members more time to accomplish all of their tasks.

Expert project managers understand that very few real-life projects stay on track throughout the entire project cycle. However, a good project manager understands how to make all three project constraints adjust to each other in order to maintain project quality. Some of the methods to keep projects within constraints are purely political: preventing stakeholders from changing the scope and maintaining boundaries around financial and human resources. Other solutions require classic project management techniques: keeping team members focused and adjusting milestones when necessary.

However, keeping teams productive under project restraints requires an often-underused skill from project managers: real leadership. When project managers believe in their assignments, they can actually use constraints to their advantage. The next four articles in this series examine each of these three project constraints in detail, sharing best practices from expert project managers while examining some of the ways that professionals refuse to let constraints become limitations.