Which type of estimate is used primarily for verifying that design is progressing within budget during various design stages?

The primary purpose of a preliminary estimate is to provide a rough approximation of costs that assists in verifying that the design is progressing within the established budget during various stages of design development. This estimate is typically generated early in the project lifecycle when the design is not fully completed, allowing project stakeholders to assess whether the conceptual designs or changes align with financial expectations.

The preliminary estimate provides a framework for budgeting by outlining projected costs based on initial design parameters and available information. This estimate is crucial during the early design phases to ensure that the project's budget constraints are adhered to as the design evolves. Regular updates of the preliminary estimate during design progress help in making informed decisions and adjustments as necessary.

In contrast, other types of estimates, such as conceptual estimates, are used for very early project feasibility studies with significant assumptions and less accuracy. A detailed estimate provides a comprehensive breakdown of costs but is typically used later when design details are more established. A budget estimate is often more general and isn’t specifically tied to the design progression in the same way the preliminary estimate is.