Efficiency multipliers for construction productivity: A Comparative Evaluation

Abstract

Efficiency multipliers for construction productivity are often estimated on an ad-hoc basis, depending on the project characteristics. The purpose of the study is to define a struc-tured approach allowing the determination of the appropriate empirical productivity relations and efficiency multipliers along with their respective values. The proposed method breaks down a given construction activity into distinct operational scenarios which represent unique combinations of key produc-tivity variables, thus providing a perspective on construction productivity for both labor-intensive and equipment-inten-sive operations. In addition, this is the first study to explicitly describe the process and the theoretical prerequisites for the statistically valid derivation and comparative evaluation of new efficiency multipliers for a given construction activity. A case study of heavy-duty concrete paving activities over an eight month period is utilized as a testbed for the derivation of new efficiency multipliers. An excavation scenario with the use of published estimation formulae is also presented to demon-strate the approach's capability to corroborate the values of known efficiency multipliers. The results indicate that the pro-posed approach improves the accuracy of estimated multipliers stemming from past productivity studies and increases the esti-mation precision for the derivation of new multipliers related to future construction operations.