Class 1: Detailed Estimate (Check Estimate or Definitive Estimate) is a project cost estimate process similarly defined by the AACE Class 1 Estimate, or the Check Estimate, or Definitive Estimate. Example. DEFINITIVE ESTIMATION: It is a more refined project cost estimate. [b] If the range index value of “1” represents 0.005% of project costs, then an … The +/- value represents typical percentage variation of actual costs from the cost estimate after application of contingency (typically at a 50% level of confidence) for given scope. This estimate requires more time than the ROM technique; however, its accuracy is between -5% to +10%. ROM and definitive estimate are types of cost estimates with a very different accuracy that are used in different phases of a project. For each type, it described four typical estimate characteristics; purpose, accuracy, information available for estimating, and methods. A definitive estimate is one which is carefully put together with due diligence in consideration of the project facts. Analogous Basing a cost estimate on the historical costs incurred by similar initiatives. The definition level is 90 – 100% and the accuracy of the estimate is 5 – 10%. The project manager is working on a high-profile project where completing the project within budget is critical. Definitive estimate: A definitive estimate has an accuracy of around -10 percent to +15 percent and in some standards, around -5 percent to +15 percent. Here, the time required to calculate the cost estimate is the least. Normally, project managers use -5% to +10% of range from actual. A cost estimate is a forecast of costs for a program, project, strategy, plan or activity. Definitive estimates: Drafted when a project’s scope and constituent tasks are almost fully defined, a definitive estimate makes full use of deterministic estimating techniques, such as bottom-up estimating. You use this metric when management needs a more accurate cost or time estimate and you have enough project information. ID 2115 a definitive estimate is. Estimate to Complete (ETC) and Estimate at Completion (EAC) If partway in a project it turns out that the budget baseline (based on previous estimates) cannot be met, a re-estimation of the project cost is required. Sometimes called as detail cost estimates, this type of cost estimation are not only more accurate than order of magnitude of estimate and budget estimate but are also more detailed. This final estimate might be considered the "definitive" estimate. A definitive estimate is based on detailed information from each work package within the WBS or estimates completed at the activity level. It was titled Estimate Types and proposed 4 types; Order of Magnitude, Preliminary, Definitive, and Detailed. The detailed estimate or definitive estimate is made when the scope of work is clearly defined and the detailed design is in progress so that the essential features of the facility are identifiable. Definitive This type of estimate applies when costs are known. The following are common types of cost estimate. Prior to any significant analysis, we developed a ROM that the project would cost $1.5M. That is, the project has been tendered (not just designed) and quotes have been received. Definitive Estimate. Definitive estimates are the most accurate and reliable and are used to create bids, tenders, and cost baselines.