Sunday, September 14, 2008

September 15, 2008 – Back to the Basic: Competing Project Constraints

Following last week’s edition, one of my project management co-conspirators dropped me a note informing me that the triple constraint (see The Troubling Triangle) is officially dead. The upcoming release of the PMBOK Guide 4th edition has killed it.

In lieu of the binding, restricting, tri-legged barer of logic, PMI has opted for “Competing Project Constraints.” The new PMBOK includes Scope, Quality, Schedule, Budget, Resources and Risk as a representative list of the numerous constraints that a Project Manager faces.

Without reading the text directly I can not make a fully informed decision about the wisdom of creating a multisided polygon constraint. For one thing it doesn’t have quite the same ring as a triangle (I’m sure there’s a bad musical percussion joke in there somewhere). However, here are my initial thoughts.

  1. I whole heartedly agree that Project Managers have more to worry about than Scope, Schedule and Budget. I don’t think there was ever any real misunderstanding of that fact.
  2. By removing the Triple Constraint and accompanying triangular image, we loose the visual used to explain the impact of changing one of the legs.
  3. Of the examples given as other constraints, Quality is easily represented by the size of the area encompassed by the leg segments of the triangle. Although not originally part of the image, it fits.
  4. Another, Resources is generally a factor of the cost (or budget) of the project. If money is no object you can get better and more resources. The New York Yankees and Real Madrid sports franchises, with their ability to buy talent, come to mind. Generally speaking, projects run out of time or money before they experience a lack in available resources.
  5. For the other, Risks, I need more explanation for the use of the term “constraint.” If the term means “factors that may adversely impact your project” then I would agree.

Perhaps that is the basis of the change in the terms used. PMI may believe that it is doing us a favor by widening the term to show the myriad of chainsaws and knives we need to keep juggling. My fear is that it opens the door for management to defy the simple logic that if they increase scope, schedule or budget, one or both of the other legs have to adjust.

If we are expanding the number of constraints, maybe we just need a different image:
Picket Fence – Each of the slats represents a constraint holding the project level.
Suspension Bridge – All of the cables adjusted to keep the path safe for passage.
Multi-legged Table – Legs adjusting together to support the project.

Whatever the symbol, I will miss the triangle.


Brian Buck said...

I have been formally studying and applying project management for 1.75 years. The triple contraint triange is the most fundamental image and concept that I have latched onto and seen its impact directly in my projects!

I agree wholeheartedly that quality is in the area of the triange since the change of Time, Cost (Budget), and Scope will have direct impact on it. I have seen other trianges where scope wasn't a line but quality was there and I always disagreed with that representation!

You are right resources are part of Cost.

I understand why the PMBOK will want to make things more consistent with the processes but I think there is a way to roll them into the classic triple constraint triange!

I am new to project management and I am already pining for "the good ol' days"!

Cornelius Fichtner, PMP said...

I'd like to add another view of "Resources as a constraint". They are not necessarily always a cost constraint. Sometimes, they are simply a constraint in themselves.

I am especially thinking of two events that happen again and again on my projects:

Availability - In the companies that I have worked for human resources have always been limited. My fellow project managers and I usually had to negotiate about who gets to use a particular resource when there were competing demands. (And even the richest baseball team cannot run out during a critical match/project and bring in another star pitcher... :-)

Ability - I also often had the situation where resources were simply assigned to my project and I had no choice but to use them. However, their abilities were far from what we truly needed. This meant that the schedule had to be adjusted.

That much said... could you throw money at these two factors and solve the issues? Probably. But in the final analysis, the problem described isn't one of cost, it's one of resources.

And that's why I agree that the traditional triple constraints are a good model for explaining relationships of competing project needs, but then you have to move on and bring all of the factors into the picture. Like the fact that the company's new policy of "no more free coffee" is making everyone cranky... ;-)

Cornelius Fichtner
The Project Management Podcast

Glen B. Alleman said...

Replace all those variables, with Techncial Performance Measurements (TPM) and you get Performance Based Earned Value (PB-EV).
This is the paradigm used in aerospace and defense program controls. is a starting point.
This concept has been around for several years inside Northrup and other contractors. It is now starting to move into the main stream.
A TPM is ANY attribute of the project's output (product or service) that is not Cost or Schedule. This is a Systems Engineering concept ( that connect programmatic controls with technical tradeoffs.

Glen B. Alleman
VP, Program Planning and Controls
Denver, Colorado