Cue-based decision-making in construction work crews: An agent-based modeling approach

Construction work crews often deal with ambiguities (e.g., mismatch between provided directives and existing situations) at the work face about ‘what-to do’. In such a circumstance, the work crew is forced to interpret cues present at the work face surroundings to make a decision. This research argues that dynamics of a construction work crew, as a collection of two or more skilled trade workers who are continuously engaged in face-to-face interactions influence its interpretation of work face cues. Dynamics of a construction work crew may be adapted to the group Input-Process-Output (I-P-O) framework where inputs such as characteristics of each member enable and/or mediate a group’s process like communication, and interaction to generate outputs – e.g., a decision. A population of one hundred and seventy six (176) construction skilled trade workers were qualitatively interviewed: (i) to learn their most-immediate actions in a situation where directives did not match the work face condition and while physical hints were present; and (ii) to identify input factors they experienced to be influential on the process of decision-making and their interactions to determine ‘what-to do’. Contents of these interviews were clustered in categories of implied descriptions, 69 percent of which suggested that these work crews were more eager to autonomously resolve the ambiguity and most-likely by discussing the issue with their crew-mates instead of contacting their supervisors (25%), or customers (5%). Contents of these interviews also revealed that knowledge and skill of crew members, their confidence and trust in others crew-mates, and their open-mindedness were discussed most frequently as impactful factors on decision making and interactions between members. In order to understand impacts of these input factors on interactions between work crew members and their interpretations of cues, an Agent-based Modeling Simulation (ABMS) was developed. The abstract ABM (in NetLogo environment) simulated a work crew of two members with uniformly-distributed levels of skillfulness, confidence, and open-mindedness who were to complete an activity by making decisions on initiating a series of tasks. The crew operation time, amount of rework it conducted, and frequency of its call-for-assistance were measured for 199,948 cycles and were analyzed with respect to input factors. Skillfulness was identified as the most influential factor on operation time. It was also realized that all three outputs measures were most sensitive to input factor skillfulness; and that each output measure was almost equally influenced by variation of the factors confidence, and open-mindedness. The research dissertation concluded that variations (or rather heterogeneity) of skillfulness, confidence, and open-mindedness in work crews would increase intensity of interactions between members, and would, thus, decrease the likelihood of expected optimum operation time, no rework, and less frequency of call-for-assistance. The core of this research dissertation offers a sound basis for construction work crew recruitment by identifying knowledge and skills as an intuitive requirement while screening for additional traits of confidence, and open-mindedness. It also provides an explanation to better understand ‘why’ the Last Planner System® (LPS) of Project Planning and Production Control is instrumental in maintaining a reliable, and predictable workflow for a construction operation.