29. The Triple Constraint, That Dangerous Dogma

“Cheap, fast, complete. Choose only two. You can’t have all three conditions at the same time.”

We have lived project management for decades following the dogma of the triple constraint:

• Scope
• Cost
• Time

Additionally, some authors have added Quality as a fourth constraint.

The Triple Constraint states that:

• You can respect the scope and cost, but you must compromise on time.
• You can respect the time and cost, but you must compromise on the scope.
• And other combinations…

This postulate (dogma) has accompanied us for many years in project management. But it is now an outdated model.

Those who continue to wield the Triple Constraint as valid will quickly find their scope of action reduced.

Because it’s very difficult to overcome the Triple Constraint, that’s true, but it’s extremely simple: you just need not to consider it a dogma.

Every time someone refuses to accept the Triple Constraint, a change occurs, innovation develops, progress is made.

Every time the Triple Constraint is accepted without question, we become mere executors of projects, without added value, without challenging established methods.