The Project Management Triple Constraint

October 10, 2009 | Author: PM Hut | Filed under: Project Management Definitions,Project Management for Beginners

The Project Management Triple Constraint
By Michael D. Taylor

Projects are usually based on three major factors, time, cost, and scope. Once these three aspects are defined it is the project manager’s responsibility to manage within the constrained values. For instance, if a project’s scope must be met at a maximum budget of $5 Million, and completed within fifteen months, then the project manager must continually evaluate the impact on cost, and time, if additional project scope is proposed.

This places the project manager in a unique role. Technical personnel tend to place their highest priority on the technical aspects of the product (scope), and give lower priority to the schedule (time) and budget (cost). Finance personnel tend to place their highest interest on cost, and generally remained unconcerned about time or scope.

The Triple Constraint in Project Management

The Triple Constraint in Project Management

When project managers face the need to trade-off one of these three constraints against another a problem arises. Which of the three is to be sacrificed in order to meet the more important one? In other words, if a proposed change in scope is being considered, and it can be accomplished by adding more personnel (cost increase), or by extending the project completion date by working within the number of available people, which is the best choice? The only way for the project manager to make an intelligence choice is by knowing the priorities of the triple constraint factors.

While the term “triple constraint” implies that only three factors are important in many cases other constraints must be considered. These may include vital aspects such as customer satisfaction, product quality, and project risks. Whatever the established constraints are, it is the project manager’s role to maintain a balance between them based on their priorities. Project managers must avoid the mistake of establishing these priorities unilaterally. Instead, there must be agreement by the project’s key stakeholders.

MICHAEL D. TAYLOR, M.S. in systems management, B.S. in electrical engineering, has more than 30 years of project, outsourcing, and engineering experience. He is principal of Systems Management Services, and has conducted project management training at the University of California, Santa Cruz Extension in their PPM Certificate program for over 13 years, and at companies such as Sun Microsystems, GTE, Siemens, TRW, Loral, Santa Clara Valley Water District, and Inprise. He also taught courses in the UCSC Extension Leadership and Management Program (LAMP), and was a guest speaker at the 2001 Santa Cruz Technology Symposium. His website is

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5 people have left comments

The PMBOK in it’s 4th edition has departed from the traditional triple constraint concept, recognizing the fact that there are more than three constraints with which the PM needs to deal. The PMBOK mentions the following as being amongst the constraints the PM needs to balance:
– Scope
– Quality
– Schedule
– Budget
– Resources
– Risk

Shim Marom wrote on October 12, 2009 - 12:09 am | Visit Link

Hi Michael,
Risks are related to the choices made in blending Costs (aka Resources or Budget), Time, Scope (that should include Quality).
The role of Project Manager should focused on working along with the Sponsor for obtaining a clear vision (what shall be done within specific allowances that cover time, scope and budget).

Eugenio Magnone wrote on October 12, 2009 - 2:49 am | Visit Link

We have an article from earlier in the year called “What’s wrong with the triple constrait?”, readers might be interested in reading more about this


Lindsay Scott wrote on October 12, 2009 - 4:14 am | Visit Link

Look at the broader view of these contraints. The US DoD uses Cost, Schedule, and Techncial Performance. Technical Performance Measures (TPM) encompase everything that is NOT cost and schedule.

The critical understanding is to state “up front” the desired Techncial Performance of the deliverable at a specific point in time. Then measure compliance with that TPM. The gap between the planned and the actual TPM has direct impact on cost and schedule.

The paradigm of defining future performance then measuring conformance with this plan is the basis of Performance Based Earned Value. See for more background.

Glen B. Alleman wrote on October 13, 2009 - 3:14 pm | Visit Link

Hi Michael,

I enjoyed reading your post. We blogged along similar lines earlier this year; might be helpful for other readers:

Laura Bamberg
Steelray Software

Laura Bamberg wrote on October 20, 2009 - 9:20 am | Visit Link

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