Control Estimates (AACE Class 2) are generally prepared to form a detailed control baseline against which all project work is monitored in terms of cost and progress control. They are the final estimate prior to project execution. All actual costs and resources will now be monitored for variations to the budget and form a part of the change/variation control program. For contractors, this class of estimate is often used as the ‘bid’ estimate to establish contract value.
Control Estimates involve a high degree of deterministic estimating methods. They are prepared in great detail to achieve the highest degree of accuracy. For those areas of the project still undefined, an assumed level of detail takeoff may be developed to use as line items in the estimate instead of relying on factoring methods. Typical accuracy ranges for feasibility estimates are between -5% to -15% on the low side and +5% to +20% on the high side, depending on the technological complexity of the project, appropriate reference information and the inclusion of an appropriate contingency determination.