Closure to “Reducing Variability to Improve Performance as a Lean Construction Principle” by H. Randolph Thomas, Michael J. Horman, Ubiraci Espinelli Lemes de Souza, and Ivica Zavřski

Benchmarking masonry labor productivity

“…Total work hours: summation of daily work hours in each project.Total quantities: summation of daily quantities in each project.Cumulative productivity: a measure of the overall effort required to finish the work.Cumulative productivity (hr/m 2 )=Total work hours (hr)/Total quantities (m 2 )Baseline productivity: the best performance a contractor can achieve for a particular design. It is calculated by applying the following steps to the daily productivity values for each project (Abdel‐Hamid et al , 2004; Thomas et al , 2002):Determine the number of workdays that comprise 10 percent of the total workdays observed.Round this number to the next highest odd number; this number should not be less than five (5). This number, n , defines the size of (number of workdays in) the baseline subset.The contents of the baseline subset are the n workdays that have the highest daily production or output.Calculate the sum of the work hours and quantities for these n workdays.The baseline productivity is the work hours divided by the quantities contained in the baseline subset.Number of abnormal workdays: it follows that high variability in daily productivity is associated with poor labor performance.…”

“…Baseline productivity: the best performance a contractor can achieve for a particular design. It is calculated by applying the following steps to the daily productivity values for each project (Abdel‐Hamid et al , 2004; Thomas et al , 2002):…”