The Iron Triangle of Project Management

               Now that Abby had determined the scope of the project to throw the party, created a schedule for her team to set up the party, and estimated the total cost of throwing the party, she could see how changes in any one of these three elements could affect the other. If extra items were added to the party, it would result in the party taking more time to prepare if any setup was required or costing more money if the extra items were purchased. So, an increase in scope would increase the amount of work time required or increase the cost of the project, if not both.

               If Abby waited two days to do any more work on the project, there wouldn’t be enough time to get all the work done, so she would be giving Nathan a smaller party, although she probably wouldn’t have to spend as much money on the ride punch cards, since her friends would have less work to do.

If the cost of ride punch cards were to double before Abby bought them (buying day-of instead of in advance), it would make her feel more inclined to buy cheaper cards that allowed fewer rides, and so she might then feel the need to assign her friends less work and put on a smaller party.

These are examples of what is called the Iron Triangle of Project Management (or the Triple Constraints of Project Management). Generally speaking, any change in one of the three elements of scope, schedule, or cost will cause the other two to change somehow as well. The hard part about working as a project manager is keeping scope, schedule, and cost all in balance so you don’t run out of time or money to complete the scope that’s needed by the end of the project.

Next post in the series: Making a Party out of Project Management: Chapter 5 - The Plan for the Team