Early Conceptual Estimating Methodologies

摘要

A common issue often faced by estimators is how to prepare an estimate when there is little information or scope definition on which to base the estimate. This article provides an overview of conceptual estimating methodologies commonly used for the preparation of Class 5 estimates. The application of preparing capital facility estimates for the process industries is used, although the techniques can be used to support estimating in other industries as well. There are many order-ofmagnitude or conceptual estimating methods, and each can be useful in a specific situation. Often, a single estimate may rely on using a combination of estimating techniques for different portions of the project. The conceptual estimating methods that will be discussed in this article include: 1. Analogy Estimating 2. Capacity Factored Estimating 3. End-Product Units Estimating 4. Physical-Dimensions Estimating 5. Parametric Estimating 6. Expert Judgement This article expands upon an earlier AACE International paper, So You Think You’re an Estimator? [6], incorporating information from AACE International (AACE) recommended practices, such as AACE RP 59R-10: Development of Factored Cost Estimates - As Applied in Engineering, Procurement, and Construction for the Process Industries [2]; as well as from other sources, such as Sharpen Your Cost Estimating Skills [5], an article reprinted in the AACE Cost Engineering Journal. This article was first presented as EST.3423 at the 2020 AACE International virtual Conference & Expo.