When undertaking a large project, it is extremely important to understand and take into account the triple constraint. The triple constraint involves three primary constraints that most projects will have: Time, cost, and scope. Time refers to the schedule or time constraints related to the project. Cost involves the budget and all other monetary issues related to the project. There is no single minimum or maximum amount of hours or dollars that defines projects overall. Each has its own requirements. Scope deals with the goals of the project, and the work involved in reaching those goals.
These three constraints are interrelated. If one constraint changes then the other two constraints will also be affected. For example, if a project team is building a new Web site for a large company, and the company decides to add an e-commerce area to the Web site, this will affect the project’s scope. The scope of the project will increase, and the time it takes to complete the project will increase, as well as the project budget. It is possible that the timeline may stay the same after the scope has increased, but then the budget would almost certainly need to be increased to account for extra personnel to work on the project.
One responsibility of a project manager is to identify which of the three constraints is most important to the project sponsor or stakeholders. Is the sponsor’s number one priority to have a fully functional product to meet customer needs, to have a product out the door by a specific date, or to have a project completed within a specific budget amount? The project will be planned and executed slightly differently depending on the priorities of the client.
Adding Quality:
The Quadruple Constraint There is an additional constraint to every project: quality. A project manager may efficiently prioritize and manage a project within a legitimate scope, within budget, and on time, but the project may not satisfy the client’s expectations.
This is where quality comes into play. In some instances, quality will be of the utmost importance to the client, and the other constraints will not impact the project significantly. In other projects the client is more interested in simply getting a product or service rolled out, regardless of the degree of quality. Some even argue that the triple constraint involves quality in the place of scope, and that when working with a client, the project manager needs to determine what the client is most concerned with: quality, cost, or time. Obviously, a client will want all three of these items, a high quality deliverable completed very quickly and at an affordable cost.
In reality, the project manager needs to decide which two are the most important in each instance, and base the project plan on those two. If a client wants something quick and at a low cost, the quality may not be very good. If a client wants something of high quality at a low budget, a somewhat longer timeline may be necessary to avoid excess staff time and overtime costs. If the client wants something quickly and of high quality, the budget will need to be higher to staff a larger project team and possibly pay overtime. As you can see, all of these items are interrelated. Be sure to take quality into consideration along with the triple constraint, as all four forms a “quadruple constraint” and are very important.
