What are the Three Primary Variables (or Triple Constraints) in any Project?

Haleema Qayyum

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Haleema Qayyum

What are the Three Primary Variables (or Triple Constraints) in any Project?

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The three primary variables (or triple constraints) have been used as a standard for any project management for several years. However, there has been a wider recognition of more than three variables in recent years. So, we can say that now there are two concepts of these variables.

One is the traditional concept, according to which there are three primary constraints for any project: Cost, Scope, and Time. The other is the new perspective surfacing around more than three variables in project management.

This article will cover both the theory and practical aspects of triple constraints that professionals of project management use.

Three primary variables (Triple Constraints)

Three Primary Variables In Project Management

The three primary variables in project management are also known as the “Iron Triangle” or “Project Management Triangle.” These three variables show the relationship between the scope, cost, and time of any project. So, let’s discuss each side of the triangle in detail.

Scope Variable

The scope of a project refers to the range, extent, breadth, reach, dimension, confines, realm, gamut, spread, or spectrum of the work required for the project. The scope also represents the sum of all the services and products that show what is being done and how much work has been done on the project.

Time Variable

It shows the total amount of time required to complete the tasks or project. In addition, it gives an estimate of when you have to start the work and when you have to complete it.

Cost Variable

The project cost variable shows the amount of cost, resources, and other finances required to complete the projects and all the tasks that are part of the project. For example, this variable might include the cost of hardware, labor, software, and other relevant charges.

Related Article: Cost Variance Analysis | Project Cost Management

Triple Constraints Triangle

How Does The Triple Constraint Work?

The purpose of the three primary variables is not only that it helps to remember that we have to enlist the scope, cost, and time of any project. The three primary variables show that any project cannot be completed without these variables in project management.

In addition, all these variables are linked to successful project management. Also , triple constraints of a project follow the give and take principle. Therefore, according to these variables, if there is any change in any side of the triangle or any variable of the triangle, the other two sides of the triangle will also get the effect.

Thus, we can say that it follows the same concept of geometry that we used to read in Mathematics.
Most of the time, the project managers place quality right at the center of the triangle. The purpose of placing quality at the center is that any project’s quality depends on these three primary variables.

It also states that when you maintain the quality while making changes in any side of the triangles, you also have to maintain the quality of the other sides. In addition, this is a natural phenomenon. For example, if you want something to deliver you fast results, you have to invest more or pay more for that thing.

Similarly, if you want to save your cost, you have to go for simpler versions or less scope. The three primary variables also work great when you do consultations and discussions with your client. It works in both stages, initially when you decide the project’s scope and later when you handle the change request in the project.

Digital scoping of projects is competitive, and the managers feel pressure to deliver the right thing comprehensively, quickly, and cost-effectively.

Why Three Primary Variables Matter for Project Management?

The three primary variables matter for any project management. When you keep all these three variables in mind, you can adapt to changes in project management. In addition, they keep you prepared for delivering the project within budget, on time, and within scope despite changes.

Any project requires changes, and getting ready for changes helps you avoid any mistakes. In addition, your project also does not jeopardize due to these changes. Therefore, it is essential to understand and manage the three variables in project management.

Not a Triangle Anymore

The opinions about the usefulness and accuracy of the triple constraints are mixed. Some believe that Iron Triangle is impractical and inaccurate. Some are stuck with the variables of the triangle. Regardless of many variations in opinions, most believe that project management has more than three constraints.

In reality, managing a project is a complex task, and it is not as easy as the triple constraints model of project management suggests. By considering the limitations of the project constraints model, the project management institute (PMI) has increased the number of variables or constraints.

The institute has realized that project managers must face more than three constraints while managing a project. So, now these constraints are included in any project constraint model.

  • Quality
  • Scope
  • Budget
  • Schedule
  • Benefit
  • Risk

Now, these are a total of six constraints. We have already discussed the three constraints above; the additional three variables in the PMBOK are:

Quality Variable

The quality variable is just like the scope variable, except it also focuses on the characteristics of outputs and deliverables.

Benefit Variable

This variable shows the value of the project that it will deliver to the company, For example, improving customer service or increasing sales.

Risk Variable

This variable shows the probability of an event that can affect the project. So, this variable shows the level of risk that a project manager or stakeholder is willing to tolerate.

All these additional constraints are legitimate project management variables. However, the simple model of three primary variables is still popular for understanding the relationship between the various dynamics involved in any project.

Related Article: Risk Register Example and All You Need to Know About It

Best Practices to manage The Three Primary Variables

There are best practices for using the triple constraints in project management in daily life. For example, you can use these variables in your daily life to understand the client’s expectations and, as a result, build parameters to make sensible changes.

The first step is to only decide on the priorities. Then you have to decide that you are inspecting the right metrics. Finally, there are various useful tools that you can use for managing the triple constraints in a project.

In addition, you can use our free project management tools and templates. Most of our templates include tracking resources, time, and scope. You can also process documentation while using these templates.

Three primary variables
Is Cost The Largest Priority?

If the cost is the largest priority, and you have no choice to cross the fixed budget, then the stakeholder needs to be flexible on scope and time frame. When cost is the main priority in any project, only the critical change requests are authentic.

So, when you have to make such changes, make sure to look to these measures:

  • Change the project deadlines
  • Cut back the project scope
  • Tolerate the reduced quality of some project deliverables

You can also use software for resource management that will help you communicate the project cost estimate to the clients. In addition, you can make reports on the team capacity, project performance, resource utilization, clients, and individuals in the software.

Is Time The Largest Priority?

When the time limit matters most, the clients need to be flexible in the other two constraints of scope and cost. When you satisfy the time constraint, you have to:

  • increase the cost by keeping more resources inline
  • scale back the quality/quality of the end project

Furthermore, when precise deadlines and estimates are a priority, you need to use the right tracking templates. Also, make sure you know how to use these templates. You can also use past reports of various projects to make the right estimates. In addition, don’t forget to track your working hours so that you can stay on schedule.

Related Article: Free Editable Blank Timeline Templates

Is Scope The Largest Priority?

If the scope is the ultimate priority, the clients need to add more features and elements throughout the project. When they find more about the clients, they have to add the details of each client. So, in such case, you have to:

  • Compromise on project timeline as the manager accommodates scope changes
  • Tolerate the over cost as the deliverables are added to the scope

It does not matter what your project is; you need to have a detailed statement of work (SOW) that will define the overall work information. In addition, this document will give information about the standards, deliverables, requirements, and criteria for each phase. You can use our free statement of work templates.

Five Frequently Asked Questions

What is an example of a triple constraint?


The triple constraint theory says that every project works within time, scope, and cost boundaries. For instance, if a client wants to increase the project’s scope by adding more features, the client has to budget more money and time to get it done.


What is the most important part of the project plan?


The most important part of any project plan is a project scope statement. The scope statement is the foundation of the overall project plan. In the statement, the manager records and finalizes all details relevant to the project to be equally involved in the project.


What is the correct order of project planning?


The correct order of project planning is:

1. Define project goals
2. Define project deliverables
3. Create a project schedule
4. Build supporting plans


What are project deliverables?


Any measurable or verifiable outcome, tangible result, or item produced to complete a project or part of a project is considered project deliverables.


What are three primary variables?


The three primary variables or triple constraints of project management are:

Time
Cost
Scope