At one point in my career, I managed a lot of software projects. At least once on each project, I would be handed the classic dilemma: “You can have it on budget or on time, but you can’t have both.” The person that was saying this to me was expressing frustration about being behind an eight ball, sometimes because of my planning, sometimes theirs and sometimes it was the accumulation of all the times we didn’t say ‘no’ to the client.
During this period, I learned about a concept called the ‘triple constraint’. The ‘triple constraint’ consists of Scope, Time and Resources. Explained below, it is a quick way to think about any situation and be able to know how difficult it will be. One way to think about it is as three forces that are all pushing against each other such that, any change in one will affect at least one of the other two.
The first force is scope. Well defined scope is at the heart of any contract, business plan or project. Simply put, scope how much work will be done and what the delivered product will look like. For a project, it is the set of tasks that will be met and the objective of the project. For a company these are the process steps that are used to deliver its product to a customer. How big the scope is drives two other forces: time and resources.
Time is literally how much time you want a task or process to take. In selling a car, two hours may be an acceptable time. Writing a contract may take 10 hours. Machining steel into a part may take a few minutes. Time affects scope because the time limit will determine how much scope you can accomplish. If you choose well in developing your scope, you should be able to accomplish the work in the time you set. Scope and time, in turn, are dependent on resources.
Resources are the things that you need to get the job done. Most think this applies to people alone, but it also can be a line of credit, a machine or anything else that gets your process steps completed so you can deliver your product. A well planned business or project will allow the work described by scope to be performed in the time allowed with the resources you select.
All these forces act on each other. A change in one means a change in the others. If you add more to scope, you will need more resources, time or both. If you have a reduction in resources, you will have to increase time or reduce scope or both.
For example, if you set contract scope for 100 parts per 8 hour shift based on your shop producing a part in 4 minutes and you find out that it actually takes 6, you have several choices:
Reduce the number of parts required by scope (result: fewer parts produced)
Add more resources in the form of additional machines (result: higher costs for more machines and labor)
Add more time in the form of overtime pay (result: higher costs for labor)
The choice you make is based the specifics of your situation. The important point is that you have a quick way of analyzing the impact of any change using the ‘triple constraint’. It’s simple and powerful. Understanding that changing any of the three elements will have an impact on at least one of the others, you can make quick assessments of business situations and rapidly come up with usable choices.
Dispatches From The Front 