2 2.1 Managers recognize time, cost, and resource estimates must be accurate if project planning, scheduling, and controlling are to be effective. However, there is substantial evidence suggesting poor estimates are a major contributor to projects that have failed. Therefore, every effort should be made to see that initial estimates are as accurate as possible since the choice of no estimates leaves a great deal to luck and is not palatable to serious project managers. Even though a project has never been done before, a manager can follow the guidelines. Evaluate the seven guidelines to develop useful work package estimates. (14)