Because the project goals you set help determine the steps required in your project plan, and thus the scope, you can start your evaluation by finding out whether the goals have changed since you started building your plan. Or, you might refine your original goals by making them as specific and measurable as possible. For example, a lofty goal such as "Produce the best product in its category" may sound good, but it’s so general that identifying all the steps required to achieve it may prove impossible. A specific goal, such as "Make this product 10 percent smaller than its predecessor," is measurable, achievable, and readily broken down into concrete steps.
As you review your goals and scope, you can examine your assumptions. If you haven’t already documented your most important assumptions, now may be a good time to do so. For instance, ask yourself the following questions:
During the course of the project, you should reevaluate your assumptions and change your project plan to take new circumstances into account. For instance, if a less-skilled painter replaces a more-skilled one, you might need to add time to your estimate for how long it will take to paint a room.