Three must-know core constraints control project management success. We review them here, along with their impacts.
What are project management constraints?
In all projects, there are three separate, but correlated, controls, which, when breached, affect one, or both, of the remaining controls.
In those cases, either the variance within the first breached control is corrected or the remaining ones need to be adjusted, lest the intially expected outcome of the overall project is compromised.
These controls are referred to as project constraints and are typically defined up front in any project.
The project management core constraints are Scope, Cost, and Time. Some also refer to these as the Triple Constraints or as the Project Management Triangle.
There is no way to avoid the cross dependencies of the three core constraints regardless of the project management methodology.
There have been attempts to add other controls to the project management process. Some of the considerations included Quality, Benefits, Risks, and Scope Management. However, the three core constraints remain the most widely followed by most project management services professionals.
Let’s define each constraint separately.
The Scope Constraint
The Scope constraint refers to the expected deliverables of a project. It identifies the project goal and defines its success. All project tasks are designed to reach the targeted outcome defined in the Scope.
This constraint states the project deliverables, the expected results, as well as the functions and features where applicable.
The Cost Constraint
The Cost constraint refers to the budget allocated to the project.
All fee-based resources required for the completion of a project fall under this constraint.
The Cost constraint may include budget for company labor, materials, and outside resources.
The Time Constraint
The Time constraint primarily refers to the expected completion and delivery date of a project. However, it also covers the project schedule at the milestone level:
- At the project milestone level, projects are often expected to reach specific objectives at specific times to allow subsequent project phases to leverage work completed in earlier milestones.
- At the project completion level, projects are always expected to be completed by a specific time frame or date. Company and/or client resources are generally allocated to accept deliverables on the planned project delivery date and ready to leverage the expected outcomes.
Project management process remediations
Let’s consider a few examples.
For these cases, we will assume that the project team work is already optimized for each of the constraints, thus muting productivity improvement considerations as a solution for the challenges presented.
We will also assume that the commitment to quality remains constant. In other words, that project stakeholders will not sacrifice quality to accommodate a stressed core constraint.
These assumptions will allow us to zero in on the distributed impact of variances amongst core constraints.
Scope Constraint Breach
Let’s first then consider a project where Scope modifications are considered.
Scope expansion beyond the original scope – defined as scope creep, is a common project management challenge.
Adhering to the initial Scope constraint would require rejecting features and functions, identified after project initiation, but needed or preferred by stakeholders nonetheless.
Accepting an expanded Scope would require an increased level of effort, which couldn’t be performed by the same number of resources initially assigned to deliver less work. And, increasing the team size would increase budget requirements and therefore breach the Cost constraint.
The increased level of effort required by the expanded Scope could also mean that the project work would take longer and could no longer be completed by the initially expected delivery date, thus violating the Time constraint.
In this case, project management professionals and stakeholders may consider one of the following remedial options:
- Adhere to the initial Scope commitment and preserve the initial Time and Cost commitments, or
- Accept the newly expanded Scope, but fail to adhere to either, or both, the initial Time and Cost* commitments.
Cost Constraint Breach
In a second example, let’s now consider a project where the actual spend is poised to exceed the budgeted spend and the Cost constraint is stressed.
Adhering to the initially planned Cost commitment might require reducing the level of effort needed, or removing or delaying expected deliverables, thus affecting the Scope constraint.
It could also require decreasing the number of resources assigned to the project to resources cost. It would then take longer for the remaining resources to complete the open tasks and delay the scheduled completion of the project, thus affecting the Time constraint.
Project management professionals and project stakeholders would then consider the following options:
- Adhere to the initial Cost commitment, but reduce either, or both, the Scope and Time commitments, or
- Accept the newly increased Cost, and adhere to the initial Time and Scope commitments.
Time Constraint Breach
- Adhere to the initially agreed-upon Time commitment but either reduce the Scope or increase the Cost, or modify both commitments, or
- Accept the newly modified Time commitment, with the delayed delivery, and preserve the initial project Scope and Cost commitments.
Prepare ahead for successful project management
Changes to any of the project management core constraint are not always predictable, so preparation for those possible variances is necessary.
Experienced project management services firms and professionals always assess the probability and possible impact of potential variances for each the three core project management constraints ahead of each project. Then, they prepare contingency plans for each use case.
The timely and effective management of these tradeoffs is often a key difference in the successful delivery of well managed projects.