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  • How to Define Project Assumptions, Constraints, Dependencies and Critical Success Factors
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Once identified, these assumptions and constraints shape a project in specific, but diverging ways - assumptions bring possibilities, whereas constraints bring limits.

At a minimum, as the project begins, assumptions and constraints must be defined for one or more of the following elements:

  • Key project member’s availability
  • Key project member’s performance
  • Key project member’s skills
  • Budget limitations
  • Internal process lead time (e.g. Procurement)
  • Vendor delivery times
  • Vendor performance issues
  • Accuracy of the project schedule dates


Project limitations typically fall into several categories.

Our project’s drivers and supporters may have preset expectations or requirements in one or more of the following categories:

  • Results: The products and effect of your project. For example, the new product must cost no more than $300 per item to manufacture, or the new book must be fewer than 384 pages in length.
  • Time frames: When you must produce certain results. For example, your project must be done by June 30. You don’t know whether it’s possible to finish by June 30; you just know that someone expects the product to be produced by then.
  • Resources: The type, amount, and availability of resources to perform your project work. Resources can include people, funds, equipment, raw materials, facilities, information, and so on. For example, you have a budget of $100,000; you can have two people full time for three months; or you can’t use the test laboratory during the first week in June.
  • Activity performance: The strategies for performing different tasks. For example, you’re told that you must use your organization’s printing department to reproduce the new users’ manuals for the system you’re developing. You don’t know what the manual will look like, how many pages it’ll be, the number of copies you’ll need, or when you’ll need them. Therefore, you can’t know whether your organization’s printing department is up to the task. But at this point, you do know that someone expects you to have the printing department do the work.

Be careful of vague limitations; they provide poor guidance for what you can or can’t do, and they can demoralize people who have to deal with them.


A task dependency is a relationship between two tasks in which one task depends on the finish of another task in order to begin.  Dependencies can be created between two or more tasks, tasks and tasks groups or between two or more task groups.

There are four types of project planning dependencies. They establish the relationships among the tasks. They are listed in the order most often used.

  • Finish To Start (FS). The first task must complete before the second task can start. For example, the task "Write code module 1" must finish before the task "test code module 1" can begin.
  • Finish To Finish (FF). The second task cannot finish before the first task finished. The task "all code tested" cannot finish before the task "test code module x" finishes.
  • Start To Start (SS). The second task doesn't start until the first task starts. The task "write training manual" must start before the task "write chapter 1 of training manual" can start.
  • Start To Finish (SF). The first task must start before the second task can finish. The task "assign coder for module 3" must start before the task "all work assigned" can finish.

 Dependencies establish the links, and the type of links, between all the tasks of a project.   Once we have prepared our Work Breakdown (AKA Product Backlog), we can establish the dependencies between to begin to identify the critical path of the project.

Critical Success Factors

CSFs are the essential areas of activity that must be performed well if you are to achieve the goals for your business or project.

By identifying your Critical Success Factors, you can create a common point of reference to help you direct and measure the success of your business or project.

As a common point of reference, CSFs help everyone in the team to know exactly what's most important. And this helps people perform their own work in the right context and so pull together towards the same overall aims.


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