Table 1.

Descriptions and equations for variables involved in the SD model.

Variables	Types	Description/Equation
Number of safety improvement	Stock	The total number of safety improvements received by coworkers in an individual’s construction crew
Number of safety feedback	Stock	The total number of safety feedback received by coworkers in an individual’s construction crew
Number of coworker safety violations	Stock	The total number of coworker safety violations in an individual’s construction crew
Perceived safety-specific social support	Intermediate	Perceived safety-specific social support = Min(1, ((Number of safety improvement + Number of safety feedback)/Number of coworker safety violations) × scaling parameter (=100))
Perceived production pressure	Intermediate	If (the productivity of work crew k >= the average productivity of all work crews) Perceived production pressure = 0; If (the productivity of work crew k < the average productivity of all work crews) Perceived production pressure = Min(1, ((the average productivity of all work crews-the productivity of work crew k)/the average productivity of all work crews) × scaling parameter (=100))
Ambivalence toward safety compliance	Output	Attitude ambivalence = min (1, max (0, (0.68 × perceived production pressure-0.13 × perceived safety specific social support))) [18]
Near-miss	Stock	The total number of near-miss incidents caused by safety violations
Accident	Stock	The total number of accidents caused by safety violations
safeGoal (safety goal)	Input	A predefined value for setting the weekly tolerable number of both near-misses and accidents
Safety performance gap	Intermediate	Safety performance gap = (near miss + 10 × accident-safeGoal)/safeGoal
Safety control pressure	Intermediate	If (safety performance gap >= 1) safety control pressure = 1; If (safety performance gap <= 0) safety control pressure = 0; If (0 < safety performance gap < 1) safety control pressure = safety performance gap
proacMan (proactive management strategies)	Input	The proactive safety management, which is different from the reactive actions triggered by the safeGoal, can control the lowest level of intensity of accident intervention measures (i.e., safety improvement rate, safety feedback rate, tolerable hazard level, and distance) before the occurrence of near-misses and accidents.
Safety improvement rate	Output	Safety improvement rate = Max(1-proacMan, safety control pressure)
Safety feedback rate	Output	Safety feedback rate = Max(1-proacMan, safety control pressure)
Distance	Output	Distance = Max(5 × (1-pracMan), 5 × (safety control pressure))
Tolerable hazard level	Output	Tolerable hazard level = Min (100 × proacMan, 100 × (1-safety control pressure))