To extract the degree of influence, the respondents were asked to rate each factor on the five-point Likert scale, varying from "not important" (1) to "extremely important" (5). In addition, the respondents were asked to evaluate the actual status of each factor based on the amount of care currently given to it. To elicit the levels of actual status, another five-point Likert scale was utilized, varying from "very poor status" (1) to "very good status" (5). The survey was carried out on medium- and large-scale construction projects in Thailand.