Looking at the Apollo program, we can see a very vivid (and real life) example of how the Triple Constraint works in a large, very expensive, politically charged and highly visible project.

Project: Put a man on the moon

“First, I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the Moon and returning him back safely to the earth.” (President John F. Kennedy, Joint Session of Congress on May 25, 1961)

Scope: Landing a man on the Moon AND returning him safely to Earth

Time: Before the decade is out

Cost: Whatever Congress will approve

What are the immutable constraints here?

Time is a the most immutable constraint. NASA was determined to meet, the late, President Kennedy’s goal to send a man to the moon and return him safely to Earth before the end of the decade. This constraint simply cannot be changed. So Dec 31, 1969 would be the drop dead date.

The scope constraint defines the specifications and parameters of the project. In this case, it’s landing a man on the Moon and returning him safely to Earth. “We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win, and the others, too.” (President John F. Kennedy, Speech at Rice University, September 12, 1962)

Cost can be modified, if approved by the “sponsor” (Congress). For all intents and purposes, the White House and Congress were prepared to spend as much as necessary to achieve the goal on time. “To be sure, all this costs us all a good deal of money. . . Space expenditures will soon rise . . . from 40 cents per person per week to more than 50 cents a week or every man, woman and child in the United States, for we have given this program a high national priority.” (President John F. Kennedy, Speech at Rice University, September 12, 1962)

Because of the tight schedule, and challenging scope, something may have had to give. While Congress was able to keep throwing money at the project, they could not add any more time to the project nor could they change the scope in any way. (As an analogy, think of creating a baby as a project. Even if unlimited funds for medical bills and care were available, from conception through gestation to birth, neither the time — 9 months — nor the scope — deliver a healthy baby — could be changed; even if we throw more people on the project. If it takes 1 woman to make baby, could we do in it 1/3 of the time if we use 3 women?!)

When the scope is immutable and you MUST get it done by a certain date — no exceptions — and throwing more money at the project will not change the parameters or change the maximum amount of time available for the work, if something to has to give, then that something could very likely be the safety and well-being of the project team.

Does this mean that it’s OK if some astronauts die during the project?

The answer is yes. In fact, some astronauts did die (Apollo 1).

Time and Scope cannot be changed. Cost can be modified but, while time and scope are the independent and immutable variables, the dependent variable of cost will have no effect (i.e., cannot change) the other two. Therefore, something will have to be sacrificed in order to meet the project deadline within time and scope. The sacrifices that might have had to be made (and, as it turned out, were made) were identified as part of the project assumptions and constraints.

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While the “triple constraint” is often viewed as an abstract concept — something out of project management text book or a PMP exam prep class, in fact, it’s a real world set of contraints with very practical considerations . . . as the Apollo project so vividly proves.

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Over the past 5 or 6 years, there has been a trend to add an additional constraint to the equation (or, at least, coordinate the original three constraints with it). This constraint is “strategic alignment.”

Norrie and Walker maintain that the added strategy constraint is central to the achievement of the other three, traditional, constraints. The project and its deliverables must result in the realization of business benefits. These benefits must be aligned with the organization’s strategic goals.  [Norrie, J. & Walker, D.H.T, Project Management Journal, Vol, 35, No.4, 47-56, 2004]

In 2009, Harold Kerzner distilled the idea of strategic alignment with organizational goals further as: “Value.” [Kerzner, H. & Saladis, F., Value-Driven Project Management, 2009. Also see : "PMI North America Global Congress, 2009, "Session Closing Remarks", Orlando, FL. October, 13, 2009.]

The Apollo program (of projects) certainly met the strategic goals of the United States in the 1960s.

As far as value is concerned, in the Rice University speech, quoted from, above, President Kennedy identified the value that the United States (and the World) would receive from the space program in general and the Apollo program in particular.

Perhaps most projects do not have the political power, unlimited funding and strategic importance of the Apollo program. Very few have Apollo’s stark consequences, let alone the level of acceptability for such consequences. Nevertheless, one of the lessons learned from the project is that even such a unique and extraordinarily large and expensive project such as this one shares the same triple constraints with the, more down-to-Earth, projects that most of us participate in today, 40 years later.

© 2009, Jerry Bucknoff, MBA, PMP