Triple Constraints of Project Management Explained & Simplified
The Triple Constraint: In project management, time (the schedule and timeline), cost (the budget that determines what resources can be used), and scope (the deliverables and activities) make up the triple constraint.
The Fast, Cheap, Good Dilemma: Projects have to choose between speed, cost, and quality, and you can't have all three simultaneously. Adjustments to scope, time, or cost affect the other two, which in turn affects project outcomes.
Triangle Teaches Trade-offs: The project management triangle provides you with a convenient way to explain the interdependence of scope, time, and cost and the necessary trade-offs to clients.
The triple constraints in project management are scope, time, and cost.
- Scope: The deliverables and activities required to achieve a project's goals.
- Time: The schedule required to be followed to deliver a project on time.
- Cost: The budget required to limit the resources used to deliver a project.
As project managers, we use the triple constraint model to explain (usually to clients and stakeholders) that they have a choice; "Do you want the project to be fast, cheap, or good?" It can't be all three simultaneously. Quality will suffer.
As you'll learn in any good project management course, the reason for this is because the quality of work is constrained by a project's budget, timeline (or deadline), and scope. We can trade between constraints, but can't adjust one of the variables, or constraints, without impacting the others.
These project constraints, or variables, are tied to one another, and can be tricky to hold in tension and manage effectively, which is where project management software comes in handy!
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What Are The Triple Constraints of Project Management?
The triple constraints are the three primary variables in project management and refer to the inextricable relationship between a project’s scope, time, and cost.
This concept is also known as the iron triangle or project management triangle, and visually represents how these three elements are interconnected in project management.
When there is a change to one constraint, something else has to give. Any modification to one constraint will undoubtedly impact the others. The project triangle can help you see what this something else is and give you a useful tool for explaining this to stakeholders or clients.
When you're managing projects, you can better explain why adding a landing page to a client's marketing campaign means you need more time or budget (or both!), or why condensing the project timeline means increased costs (due to the additional resources required to hit that timeline), no matter which project methodology you’re adhering to.
Scope
Project scope refers to what's being delivered: the extent, range, breadth, reach, confines, dimension, realm, gamut, spectrum, or spread of the work that’s to be done on a project.
The scope statement encompasses the sum of products and services to be provided, describing what’s being done and how much of it.
Here are some examples of what a project scope includes:
- Project complexity: The intricacy and sophistication of the project's components.
- Output quality: The standard and excellence of the final deliverables.
- Number and complexity of features: The intricacy and quantity of functionalities within the project.
- Level of detail: The depth and thoroughness with which components are addressed.
- Quantity of finished products: The total number of completed deliverables or products.
Time
Project time is the duration or amount of time (usually expressed in number of hours) required or allocated to complete the project or tasks within the project.
Time management includes:
- Overall project timeline: The comprehensive schedule outlining project milestones and completion dates.
- Number of project phases: The divisions or stages through which the project progresses from initiation to completion.
- Time allotted for planning and strategy: The designated duration set aside for strategic planning and preparation.
- Hours worked on project: The cumulative amount of time invested by the team towards project execution.
- Internal calendars and goalposts: The specific timelines and milestones established internally to track progress and achievements.
Cost
Project cost refers to the resources—financial and otherwise—required for project execution. Costs might include labor, hardware, software, and other charges.
Project cost management takes into account factors like:
- Financial budget: The allocated monetary resources for the project's execution.
- Number of team members: The count and salary of individuals involved in executing the project.
- Equipment and facilities: The necessary tools, technology, and physical spaces required for project implementation.
Why Is The Project Management Triangle Important?
The project management triangle helps project managers with informed decision-making and expectation management, which ultimately leads to more successful project execution. Here are a few other reasons that the triangle is important.
1. Establishing Realistic Project Goals
The project management triangle helps you set realistic goals and assess whether the project is feasible by taking into account the relationship between scope, time, and cost. It can help you visualize resources, and better understand how they will impact other aspects of your project.
For instance, when facing a project with both a limited budget and a tight deadline, you can use the project management triangle (along with your project budget software) to evaluate whether the deadline can actually be achieved with the available budget before the project starts, instead of discovering this when you're already halfway through.
2. Aiding Effective Communication with Stakeholders
The project management triangle helps you better communicate with stakeholders. You'll have a better understanding of the trade-offs involved in your project, so you can clearly convey the limitations and constraints to stakeholders right from the beginning and better manage their expectations.
When stakeholders possess a solid grasp of the project's scope, timeframe, and financial plan, they become empowered to offer valuable insights and make well-informed decisions. This openness enhances trust and encourages collaborative efforts.
3. Avoiding Delays and Cost Overruns
The project management triangle helps you foresee and address potential delays and cost overruns. You'll be able to pinpoint potential risks and create backup plans to handle them.
For example, if the scope of a project expands without a corresponding increase in time or budget, you can quickly evaluate the impact on resources and make necessary adjustments to the plan.
How Do Triple Constraints Work?
Simply put, if you make changes to one side of the triple constraint triangle, it also affects the other sides of the triangle. Choose fast, cheap, or good—but when you pick one, know it'll impact the others.
The premise of the triple constraints of project management is that the three factors of scope, project time, and cost are inextricably linked.
The most common triple constraint model places “quality” in the center of the triangle to illustrate that the quality of a project depends on the project’s scope, budget, and time spent.
If you want to maintain a consistent level of quality (or, in geometry class, a consistent area within the triangle), making changes to one side of the triangle requires the other sides to adjust.
Math aside, the way the triple constraint affects projects is simple:
- If you’re going to ask for something to be delivered faster (time), you have to pay more (cost).
- If you’re trying to save some money (cost), sometimes you can achieve this by delivering a simpler product, or fewer things (scope).
The Fast, Cheap, & Good Myth
In a competitive environment, it’s common to feel pressure to deliver something comprehensive as cheaply (and quickly!) as possible.
While that is possible in some scenarios, the project management triangle reminds us that, most of the time, projects cannot be simultaneously cheap, good, and fast. We have to know our priorities to help the clients and stakeholders decide “what’s gotta give”.
The triple constraint theory is especially helpful in conversations with clients, both when initially determining the scope of a project and when handling change requests along the way (you can find a template for change orders at that link as well).
How To Manage The Triple Constraints
Although simplistic, the triple constraints of project management are often a useful way to set, and reset, expectations of what's feasible to deliver or adjust within the constraints of a project's scope, cost, and time.
Here’s how to manage the triple constraint model and use it in conversations with clients about changes to project cost, time, and scope, as well as tips to establish a go-forward plan for the project based on your clients’ priorities.
How To Manage Cost Constraints
If you absolutely have to stay within a fixed project budget, then the client may need to be more flexible on timeline and scope. With delivering on budget as the biggest priority, it’s likely that only the most business-critical change management requests will be approved.
So, when cost conversations come up, either to reduce the budget or not provide additional budget, you’ll need to:
- adjust the project schedule
- scale back the scope of the project
- agree upon reduced quality of select project deliverables
How to deal with a change in cost and budget
When sticking to the budget is a priority, you should take a moment to set yourself up with the right time tracking tools: use past project reports to make accurate time estimates and carefully track team member hours to make sure you’re not going over budget, and that you're staying on schedule and hitting milestones as the project progresses.
When adjusting scope, you should also update your statement of work to redefine the scope and quality of project deliverables, and be sure to adjust tasks in your task management software.
How To Manage Time Constraints
In cases where the deadline matters most, then more flexibility will be required with respect to the cost and/or scope.
Expediting the project to satisfy the time constraint might mean:
- putting more resources on the line, increasing cost
- cutting back the scope and/or quality of the end product
How to deal with a change in timeline
When sticking to the timeline or expediting delivery is a priority, you should use a Gantt chart to create an updated project timeline and detailed work breakdown structure (WBS) to illustrate how the project schedule and deliverables will need to be adjusted.
It's important not just to create a timeline in isolation but to use resource management software, to ensure you can allocate the resources you need to deliver the project, monitor the project team’s capacity and utilization, and keep an eye on project performance.
How To Manage Scope Constraints
If scope matters most, because the client needs flexibility to add features throughout the project, then it impacts the project timeline and cost. This is known as scope creep when scope is added by the client, or as gold plating if it's done by the project team.
If what matters most is being able to accommodate the features that are in scope, then the client has to remain open to:
- flexible timing as the team accommodates scope changes
- increased cost for adding deliverables to the scope that were not included during project planning at the outset of the project
How to deal with a change in scope
When scope management and additional deliverables are a priority, similarly to the changes to timeline and cost, you'll need to update the statement of work, the budget, and project schedule, as well as team tasks and resource plan.
A Triple Constraint Example
So, how does this work in practice? Let’s take a website development project:
- Scope: ecommerce website
- Time: 6 months
- Cost: $500,000
Let's say that according to the original statement of work, the client agreed to supply content from their team, including SEO-friendly product descriptions.
But they’ve recently learned that their team doesn’t have bandwidth to produce the content, and so they’re asking your project team to do it instead.
You can help (and adjust the project scope)
Although you might like to simply say yes to this request, and be nice and helpful, the iron triangle reminds project managers that saying yes comes with consequences.
We can’t increase project scope and do that extra content copywriting without factoring in its relationship with time and cost.
Of course, the client wants this extra work for free. They would prefer to change the scope without the time or cost of the project being impacted (this is what's called scope creep, which is a whole issue in and of itself).
A savvy project manager understands the dynamic between scope, time, and cost—and you know that trade-offs are inevitable. To deliver a successful project, the project manager must help key project stakeholders understand this dynamic, too.
How to explain the impact of changes
So, how do you navigate that conversation? The key is not to say no to the request outright. Of course, anything is possible, you're a project manager!
They key is to say, “We could do it, and change…”
- the project schedule, which will need to shift back a week OR
- the scope of another deliverable, or functionality OR
- the client needs to fund an extra week of work
You know best which lever to pull to get your client to agree. If they still aren’t getting it, whip out the diagram from this article and explain that quality suffers if the constraints change (as do the chances of project success). That tends to spook ‘em.
Additional Tips For Managing The Project Management Triangle
You have to balance the three constraints to effectively manage the project management triangle. Here are five strategies to do this successfully.
1. Analyzing & Prioritizing Activities
Analyze and prioritize activities to ensure that resources are allocated in such a way that you'll be able to accomplish project objectives. The idea is to complete critical tasks first while evaluating which tasks can be delayed or eliminated.
Don't forget about resource allocation! Consider the costs, personnel, materials, and any outside services that are required for a task. Then, analyze availability and factor in existing or competing workloads. This way, you'll notice any bottlenecks early on.
2. Keeping an Eye on Project Progress
Regularly monitor and control the progress of your projects. This will help you identify any deviations from the schedule, cost, scope, or quality of the project.
Throughout the project, you should be continuously tracking the project's performance against the baseline plan and identifying any deviations or potential risks.
3. Regularly Sharing Project Updates With Stakeholders
Early on in the project, establish transparent channels for sharing information, foster active listening, and ensure a constant flow of communication.
Provide regular updates on project progress, milestones, changes, and potential impacts so your stakeholders remain informed. This allows them to provide timely feedback, voice concerns, and make collaborative decisions.
4. Keeping Risks Under Control
Project risk management isn’t so much a process as a lens to see your project through. You need to proactively identify and handle potential project risks that could affect the triple constraints. Develop contingency plans to address any possible issues and minimize their impact on the project.
5. Use Project Management Software
The right project management tools are immensely helpful for keeping track of the many moving pieces that impact the project management triangle. Whatever the nature of your project, there’s a tool that can help to reduce the mental load of managing time, budget, and scope.
Look for a tool that offers features compatible with your work environment, such as specialized software for agile project management, Scrum, or waterfall teams, or with functionality to generate visual aids like Gantt charts.
Beyond The Triangle: Why The Triple Constraints May Be An Octagon
Despite its longevity, opinions vary as to the accuracy and usefulness of the project management triangle. Some theories have stuck with the triangle concept but changed the types of constraints on each side.
Regardless of the varying perspectives, every PM knows that managing a project is always more complex than the 3 iron triangle variables suggest, it's probably more like an octagon.
The Project Management Institute (PMI) agrees. In its latest version of the Project Management Body of Knowledge (PMBOK), PMI recognizes that project managers usually deal with more than three constraints that may shift throughout the project life cycle. These might include resources, quality standards, sustainability guidelines, or regulatory compliance requirements.
Despite the added complexity, the triple constraint model is still a great way to conceptualize the relationships between the high-level dynamics involved in project management.
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