• Scope
One of the most overlooked constraints; scope has to be managed carefully. Here is why:
If scope is increased or changed constantly, then cost and time are increased since you now have more to do. If you don’t increase the time when the scope increases then since you have more to do it may decrease the quality of the final product or service and therefore the satisfaction of the customer.
The scope must be frozen once all stakeholders approve it so that the rest of the project activities can continue. There are other methods for dealing with scope changes that are outside the scope of this article
• Time
Time is one of the 2 most watched over constraints along with cost. If time is changed the schedule is obviously affected; the project may finish earlier or later but, at a price. If time is reduced, then the scope has to be reduced or the quality will suffer and therefore the satisfaction of the customer. If time is increased, then it is probably due to a scope change; the cost of the project also increases
• Cost
The project cost is the other most watched over constraints, to the point that many times projects have a cost even before they have been planned. I know, “that’s the way it is”. But, if that’s the way it is, then something has to give and usually that is scope. If cost is reduced, then the scope of the deliverables has to be reduced or the quality and customer satisfaction will suffer. If the cost increases, then it is probably due to a scope change and therefore the time will most likely increase
• Quality
The quality of the project deliverables is, for the most part, completely delegated. Quality affects the customer satisfaction and it is what may prevent that customer from coming back for more. Quality is compromised when the project scope, time and cost change or are arbitrarily imposed
• Risk
Not planning for risk is risky. Risk management starts even before the project starts; it should be a driver for project selection. If risk is not considered or anticipated then the project scope, cost, time, quality and/or customer satisfaction will be impacted
• Customer satisfaction
Who cares if the customer is satisfied or not with the project deliverables as long as we get paid for what we did, right? Wrong. A satisfied customer is a repeat customer is a repeat revenue is a repeat profit. Then, there are the intangibles such as referrals, word of mouth, etc that helps bring more new customers. Never overlook customer satisfaction

As you can see, the “six” triple constraint all work together and the lack of attention to any one of them affect the others. They must be well managed. Don’t you think so…? Well, I do.