Correlations between calculation parameters directly influence the results of probabilistic calculations and their interpretation. In Monte Carlo simulations carried out to systematically integrate uncertainties into the calculation process, input parameter correlations are reflected by correlation coefficients and predominantly influence the chance/risk ratio and ranges of results. Correlations are usually determined indirectly by analyzing existing data series gathered from measurements, surveys, experiments etc. and investigated with respect to their linear relationship. Another option is to directly determine correlation coefficients based on expert surveys. In 2015-16, Kummer and Hofstadler conducted a survey at Graz University of Technology in which experts provided estimates of the coefficients corresponding to the correlations between certain parameters. These considerations concentrated on the labor intensity of reinforced concrete works expressed by the total labor consumption rate, which indicates the amount of labor required for reinforced concrete works per cubic meter of concrete. The total labor consumption rate of reinforced concrete works must consider all activities carried out within the system, such as shuttering, reinforcing and concreting. This paper presents and interprets survey results shown in violin plots, and M-estimators are derived to deliver sound recommendations for considering correlations when determining the total labor consumption rate of reinforced concrete works. An example demonstrates the influence of input parameter correlations on calculating the total labor consumption rate of reinforced concrete works.