Overview Project estimating is difficult. A familiar saying is 'the most accurate estimate can be determined when the project is finished', but obviously that is too late. In general, projects have to be estimated before they are started. Unfortunately, not all the information needed to estimate is available during the early estimation process. At that point, there are plenty of unknowns and the strategy to build the application is not fully thought through yet. Equally problematic, the estimation process might occur before the Use Cases are created.