Estimating: The input into good project planning

The application of project management systems has grown rapidly in all economic sectors and industries. The growth is expected to continue with the implementation of new and more complex computerized planning and control systems. However, these systems are only as good as the input or estimates of time, cost, and resources. In this paper we review the literature on the procedures and techniques used to develop good estimates. These techniques are generically summarized to be applicable in any project. We break down some considerations that should be understood prior to estimating. We conclude that not all estimates should be evaluated with the same level of effort and concern. Finally, we define an estimate, summarize rules for developing better estimates, and develop a checklist of constraints and considerations.