Which estimate class is most detailed and is associated with 50% to 100% level of project definition?

The class of estimate that is most detailed and corresponds to a project definition level of 50% to 100% is the Class 1 Estimate. This type of estimate is characterized by high precision and is typically used for finalizing costs and tendering. Class 1 Estimates are derived from detailed designs and are based on comprehensive data, including final project specifications, quantities, and rates.

At this level, the cost estimates are tailored to reflect the actual construction scenarios, providing a very high level of accuracy. This is particularly important during the later stages of a project when the project definition is nearing completion, ensuring that all potential costs are accounted for.

In contrast, the other classes of estimates do not provide the same level of detail. Class 2 Estimates have a wider range of accuracy and are fitted for projects that are in the earlier design phases, whereas Class 3 and Class 4 Estimates cater to even less defined stages of project development. Thus, the detailed nature of the Class 1 Estimate, combined with its alignment with a high level of project definition, makes it the correct choice in this case.