The project management triangle consists of three variables that influence the quality of a project. They are the project scope, cost, and time.

The triangle above shows how these three variables are linked, where if  one of the variables is changed, the other two must be adjusted in order to keep the triangle connected. If changes to the other variables are not made to offset it, the triangle will break and the quality of the output will suffer.

Project scope refers to the “size” of the project in terms of the quality, detail, and magnitude of the project’s deliverables. Controlling project scope is especially critical, as adjustments to the project  scope almost guarantees an impact to cost and time.

Elements of scope includes:-

• Project complexity

• Quantity of the finished product

• Level of detail

• Number and complexity of the features

Project cost refers to the resources both financial and non-financial that are required for the project to be completed. In some cases, the project costs are fixed and cannot be changed; while  in others, costs are variable and can be adjusted to meet project needs.

Elements of cost includes:-

• Financial budget

• Number of team members

• Equipment and facilities

• Key opportunities

Project time or duration refers to the amount of time that is required for the completion of  the project. Managing time is closely related to managing tasks, as the overall timeline is broken down by individual tasks and their anticipated timing.

Elements of time includes:-

• Project timeline

• Hours worked on the project

• Time allotted for planning and strategy

• Number of project phases

• Scope and Time

Scope is directly proportional to time. 

You can reduce your project scope to also reduce your project duration if you’re running behind schedule. In the opposite case, the length of your project timeline will increase if the project stakeholders come up with extra project activities.

• Scope and Cost

Scope is directly proportional to cost. 

By reducing the project scope, you’ll need to execute fewer tasks, which means lower costs. In the opposite case, a larger project scope would mean higher costs.

• Cost and Time

Cost and time are inversely proportional to each other. 

These two factors move in opposite directions. If costs need to be cut, then deadlines will have to be extended as you will not be able to allocate enough resources and you will need longer to complete the task.

The triangle is balanced when the scope is equal to the combination of cost and time. To keep all three elements in check, it is important to have a deep understanding of each individual variable in order to determine which should be flexible to accommodate changes throughout the project depending on the project nature. Here are some examples of scenarios. 

If you want to add to the project scope, one or both of the variables on the right must be increased in order to balance your triangle. 

For example, when the project requirements or number of product features increases but the budget remains the same, the project duration must be increased as the project team may lack the necessary budget to obtain more resources to help complete it in time and would need more time to include the added requirements.

If one variable on the right is decreased, the achievable scope must also be decreased unless adjustments are made. 

For example, if the deadline for the project is brought forward but the budget remains unchanged, certain features will not be able to be included in the final product as the team may not have enough time or resources to complete it. 

• Choose Your Priorities

The central concept behind the project triangle is that no project can be successful with three rigidly fixed points. Therefore, at least one point needs to be flexible, so that there is room for adjustments if they become necessary.

• Set Clear Expectations And Communicate Them

Once the limits and priorities of the project have been established, it is essential to communicate them clearly to the stakeholders in the project to prevent unmet expectations and unhappy owners. 

• Monitor And Update Frequently

Once the scope, cost and time frame have been established with the stakeholders, it is essential to constantly monitor for any potential changes or predictions and update them to the stakeholders regularly. Here are some examples of how each element can be monitored.