Beyond the Triple Constraints
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Abstract
To define project management success, the Triple Constraint (also called the Iron Triangle) has traditionally been applied in order to balance between key factors that constraint the overall project delivery. Regardless of a project´s size and degree of complexity, there will always be constraints to bear in mind throughout the whole project. The Triple Constraint model points out that a project manager is assumed to reach a reasonable and balanced trade-off between competing and visible constraints, in order to deliver in time, cost and scope.
After including quality as one of the key constraints, other constraints have also proved to be essential in project management. Factors such as; Resources, Customer Satisfaction, Risk and Expectations. Regardless of the constraint model´s shape, the constraints depend greatly on each other and will be adjusted depending on the particular project. This paper will outline the traditional approach of the Triple Constraint, together with some project success factors beyond the three primary objectives and the relationships between them.
In reality, a project manager is challenged by numerous constraints apart from the “measureable” mentioned factors; A project needs ground rules for communication and behavior, in addition to awareness around the individual´s needs for motivation and confirmation. These “soft pyramid sides” are related to internal satisfaction, and have traditionally been considered as complementary to the core trade-offs of the Iron Triangle, which will not be sufficient enough in many cases.
Big Idea
The Triple Constraint model is formed by three dimensions; time, cost and scope, and one side of the model/triangle cannot be changed without affecting one of the other sides. Briefly explained, scope represents the total amount of work involved in delivering a project, cost refers to the total costs of carrying out the project and schedule/time reflects the estimated or allotted time set till project delivery.
Purpose
The model has been used since the 1950s, and project managers have been measured by their ability to balance the key factors/constraints of scope, cost and schedule. In the past, projects had somewhat more certainty in outcomes, as the main source of uncertainty was in the technology that was taken into use. The model used to provide metrics for management measurement, evaluation and control, resulting in a clear and visible evaluation of how well projects were carried out after they were finalized. In addition, the model provided success criteria for evaluating options for decision-making.
Current state
George E. P. Box stated “All models are wrong. Some are useful.” (1979)
Since the 1950s, the uncertainty in projects has increased, which in turn has led to a reduction of the model´s efficacy. With more uncertainty, the constraints of the model start to cause, not solve, issues. Moreover, when using the model project managers focused on satisfying constraints, instead of focusing on customer satisfaction. This results in a project delivery within the allotted time, but the customer will not be satisfied by this. Yet, since the project was delivered near budget, it was often considered successful.
For project nowadays, the extent of uncertainty is highly present, indicating that it is impossible to determine a fixed scope, cost and schedule in advance of any project. The three factors of the model that was earlier looked upon as variables, had to be considered as constraints instead.