In the triple constraint don't you think that quality is the most difficult one to track and quantify? Is there a method where on how you can quantify the quality metric?
Firstly, let us define what the triple constraint are:
Scope - this is used to provide a common understanding of a project. It includes a justification for the project, and the what the expected results of the project will be.
Time - This is the amount of time it will take to complete the project. It is important to estimate the correct timing; otherwise, it could be a logistical and financial disaster.
Quality - The 'end perception' of the product. How your client views your product. There could be high costs associated with low quality. I will elaborate more on quality soon.
Now with regards to tracking and quantifying - I think that initially it is hard to quantify the scope of a project. You need to be very specific and clear in your scope since it sets the pace of the rest of the project. If the common understanding is weak, then it will be confusing for all of the different departments in the company. It needs to be crystal clear for all parties.
The scope should be consistent throughout the project - any changes in scope will have a negative effect ...
This solution discusses triple constraint.