Budget Authorisation Estimates (AACE Class 3) are typically prepared to support full project funding requests and as such may also form the initial control budget for the project. Estimating methodology is more deterministic than stochastic and generally involves a high degree of unit cost line items. Depending on the requirements of the client, Class 3 estimates may be the final estimate for the project against which all costs and resources will be monitored. Typical accuracy ranges for Class 3 estimates are between -10% to -20% on the low side and +10% to +30% on the high side, depending on the technological complexity of the project, appropriate reference information and the inclusion of an appropriate contingency determination.
