What is the accuracy range typically associated with a Class D estimate?

A Class D estimate, often referred to as a conceptual or order of magnitude estimate, is typically associated with a significant range of accuracy, usually around 20%. These estimates are usually made in the early stages of a project when detailed information is limited, allowing for a rough assessment of potential costs.

The purpose of a Class D estimate is to provide stakeholders with a general idea of financial feasibility without requiring extensive data, which is often not available at this early stage. The wide accuracy range of 20% reflects the high level of uncertainty inherent in the preliminary phase of project planning. This level of estimate is primarily intended for budgetary purposes and to assist in decision-making regarding project viability. As the project progresses and more detailed information becomes available, the accuracy of estimates can improve significantly.