What are the Constraints of Project Management Triangle?

What are the Constraints of Project Management Triangle - Taskque Blog

Project management has evolved over time and today it has taken a form of a growing domain. From project management methodologies to processes, project management has gone through a paradigm shift. New project management methodologies have emerged and overshadowed their older counterparts.  In this article, we will try to evaluate the effectiveness of an old project management methodology known as Project Management Triangle or Iron Triangle. Let’s take an in-depth look at what project management triangle really is and whether or not it is still relevant in today’s dynamic project management arena as it used to be a few decades ago.

What is Project management triangle?

What is Project management triangle - TaskQue Blog

Project management triangle is a model that focuses on three key constraints of a project. With each corner of a triangle depicting a constraint, project management triangle reflects that the success of a project depends on how project managers deal with these constraints.

Constraints of Project Management Triangle:

The three constraints of Project Management Triangles are as follows:

  1. Time
  2. Cost
  3. Scope
  • Time – Every Minute Counts So Don’t Waste It

Time - Every Minute Counts So Don’t Waste It - TaskQue Blog

According to the Project Management Body of Knowledge Guide, time constraints include planning and defining activities as well as rearranging activities in order and estimate resource requirements. Preparation of a schedule to accommodate all these activities is also a part of time constraint. Project management software and scheduling software can make the process of scheduling and controlling activities much easier.

Making a well thought out plan and define each activity and how much time it would take to complete. More importantly, you must arrange all the activities so that the order in which these activities will be performed is well known. This will make things easier for project managers increases the chances of success. By undertaking all these activities effectively, you can easily complete your project before the deadline.

  • Cost – Keep An Eye On Expenses

Cost - Keep An Eye On Expenses - TaskQue Blog

Completing the project inside the allocated budget can be quite challenging for project managers. According to latest statistics, large IT projects exceeded their budgets by 45% but delivered 56% less value, which is quite alarming for project management fraternity. You can manage your finances effectively with project management software as it keeps track of all the expenses.

Cost constraint in the project management triangle focuses on financial aspects of a project such as estimating cost, taking measures to control project costs and cost contingency to name just a few. Additionally, risk management and other budgeting aspects are covered under project management triangle. If you want your project to complete inside the budget, then you must focus on budgeting and cost control.

  • Scope – Don’t Let It Grow Too Much

Scope - Don’t Let It Grow Too Much - TaskQue Blog

The third constraint in the project management triangle is the scope. It encompasses milestones, goals as well as the deliverables. Keeping the scope under control is critical otherwise; scope creep will have a detrimental impact on your project. Before delivery, it is important to make sure all the features as working as defined. 

According to Project Management Institute’s pulse of profession global survey, 44% projects completed in the year 2015 faced project scope creep issues. According to another survey conducted by Geneca, almost 77% project team members say they have to deal with continuous rework and scope creep issues even after the initial agreed-upon feature have been delivered. This goes to show the scope problems that affects modern projects.

Evolution and Variants

As time went by, project management triangle evolved and many of its new variants appeared. Time and cost remained untouched but goal, deliverables, quality and product replaced scope in different variants. Project Management Body of Knowledge 4.0 introduced much more detailed model including six constraints. It is a six-pointed star formed by the combination of two overlaid triangles. The new constraints were risk, quality and resources.

STR Model

STR Model - TaskQue Blog

STR stands for Scope, Time and Resource. It is a mathematical model, which converts the visual representation of project management triangle into an expression. This expression is widely used for calculating the scope of the project but project managers can also calculate time and resources required by manipulating the expression.

Scope = Time x Resources

In simple terms, this expression represents that the scope of the project is equal to the product of time and resources. A project consuming more time and resources will have a larger scope. Project managers who do not want their project scope to expand out of proportion should make an effort to cut down on time and resources spent on it.

Drawbacks of Project Management Triangle Model

Drawbacks of Project Management Triangle Model - TaskQue Blog

Project management triangle is an old project management methodology. Hence, there are many flaws in this project management triangle, which has made it unfit for today’s dynamic project management world. Let us look at some of the drawbacks of project management triangle in the light of a survey conducted by Projectize Group.

According to a survey conducted by Projectize Group, most project managers consider these factors as drawbacks of project management triangle.

  • Not well suited for today’s dynamic project management environments
  • No consideration for customer satisfaction
  • Ignoring end user adoption
  • No focus on quality of delivery
  • No emphasis on business objectives


Project management industry has evolved tremendously in recent years so much so that new methodologies are introduced every year to keep pace with the ever-changing project management landscape. Old project management methodologies become obsolete as they fail to deal with latest project management problems. This rule also applies on project management triangle. Although, project management triangle tried to evolve but failed to keep pace with the evolution of project management industry, which was more complex now than it was back when project management triangle model was introduced.

For today’s complex projects, a simple model like the project management triangle that only touches on three constraints could not work. Although, it is a good starting point for budding project managers as it highlights the fundamental aspects that project managers will have to take care of. To deliver a quality final product and save your project from disaster, you should stay focused on time, cost and scope of the project as defined by project management triangle.