We’ve talked about how useful the project triangle (RIP: The Project Triangle) is for understanding the dynamics between scope, time, and cost on projects. Now we are going to see how useful it is in making decisions about controlling projects.

Every project is launched with an explicit or implied priority scheme for the project triangle. This priority scheme establishes which side of the project triangle is most flexible (lowest priority) and which is least flexible (highest priority) when it comes to leveraging one side to benefit another. In fact, all project planning efforts use a priority scheme to create the initial estimates of what is going to be built, how long it will take, and how much it will cost.

The majority of projects start with scope being the highest priority and therefore time or cost must flex to meet the demands of the scope. Sometimes the number of resources is limited, making time the most flexible; this is when the project end date is determined by planning efforts and not stakeholders. In other situations where scope is the highest priority, the project’s end date may need to be within a 6 month window; this is when the number of resources and money need to be readily available to accommodate the scope and time.

Many different factors determine the priority scheme for projects. If the project deliverable is aimed at beating your competition to market, then time will be the highest priority. On these types of projects cost will be identified as the most flexible side of the triangle. If the project is going to use an iterative methodology for development, there too, time will be the highest priority. Each iteration will be time-boxed to accommodate the development approach, and the number of resources will be held somewhat steady forcing scope to flex the most. In tough economic times, cost will be the highest priority. This is also true of projects that are funded by grants. In each of these situations scope will be the most flexible because there usually is a time frame the project needs to be completed in.

It would be nice if priority schemes remained the same over the life of a project, but unfortunately they don’t. Some of the changes may be driven by external fluctuations in the business environment: economic cycles, competitor behavior, customer demands, etc. These can happen from time to time; however, the vast majority of priority changes happen because of the specific time in the project life cycle: major intermediate milestones or project completion. Take for example a project with the scope as the highest priority. As the project nears completion, the stakeholders often become impatient and want the major deliverables sooner than later. Now, all of a sudden, time is the least flexible and cost is the most. In iterative developments, as they come to the end of the time-box, it may be most beneficial to make scope the least flexible and time the most. This is because it may take longer to pull out features than to keep them in and finish them late.

Decisions made on projects based on priority schemes usually are critical in nature. For this reason they need to be explicitly agreed upon and communicated. When the project is being planned there should be an agreement with stakeholders about which side of the triangle is the most flexible and which side is the least. Remember, as the project progresses the prioritization can change. It’s not as though there is a specific point in time when the prioritization scheme changes, it usually is discovered over the course of many decisions. But, when it becomes clear, the recognized change needs to be agreed and communicated amongst all project stakeholders. As with all projects, the more clarity people have regarding the project’s environment, the more consensus you will have when making decisions and the quicker the project will be completed.