## 3 Methodology
### Fall Protection Plan Decision-Making Model
#### 3.1.1 Evaluate Construction Fall Protection System Alternatives Using AHP  
Using the AHP method, the multiple decision-making criteria can be broken down into two levels based on safety regulations and relevant literature, and analysis of expert opinions in the research area, as shown in Table 1. The first level comprises the main criteria, including: safety effectiveness, system implementation feasibility, construction productivity and cost. The second level consists of sub-criteria affecting the fall protection system selection. Figure 1: Research workflow of the safety performance assessment model procedure. Safety effectiveness is a key factor for fall protection and helps planners and construction managers to judge if the fall protection system can prevent worker crews from hazard areas and effectively protect crews from injuries. As the construction workforce is the most valuable resource in construction, the protection plan alternative should protect the workforce effectively during all phases in construction. For the safety effectiveness criterion, the sub-criteria of protection appropriateness, end-user stability, and protection to user and passivity were selected as the influential factors. Implementation feasibility is a critical factor for fall protection system selection, because safety measures must be easy to implement to save time and cost. Before the task starts, a construction worker needs to put on the fall protection system (e.g., fall arrest system) in advance, therefore, the safety measures should be feasible and convenient to apply. Specifically, four sub-criteria were selected for the implementation feasibility, including the equipment installation simplicity, aesthetics of protection system, effort needed before installation and flexibility. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Criterion** & **Sub-Criterion** & **Definition** \\ \hline \multirow{6}{*}{\begin{tabular}{c} Safety \\ effectiveness \\ \end{tabular} } & Equipment & Selection of appropriate fall protection equipment according to the task features and installation conditions on the \\  & appropriateness & jobsite [11; 27; 40; 58; 59; 60]. \\ \cline{2-3}  & End-user stability & User stability on platform surface or construction components \\  & & using protection system [11; 61]. \\ \cline{2-3}  & Protection to user & Protect workers from fall hazard area [11; 16; 29; 58; 59; 62]. \\ \cline{2-3}  & Passivity & The protection should be passive and does not need workers’ \\  & & operation and participation after the system is installed [16; 29]. \\ \hline \multirow{6}{*}{\
\begin{tabular}{c} Implementation \\ feasibility \\ \end{tabular} } & Simplicity & The protection plan should be easy to implement using common resources and not difficult to understand [16; 29; 58; 62]. \\ \cline{2-3}  & Aesthetics & The appearance of the construction structure after the protection system is installed [16; 58]. \\ \cline{2-3}  & Effort needed before installation & The need for extra effort to install the protection equipment if working near fall hazard area [58]. \\ \cline{2-3}  & Flexibility & The applicability of protection system that is being applied to various task conditions and different phases of construction [29; 63]. \\ \hline \multirow{6}{*}{
\begin{tabular}{c} Construction \\ productivity \\ \end{tabular} } & Labor productivity of executing tasks & Productivity of work crews and labor performance using the protection system [29; 58; 64]. \\ \cline{2-3}  & Ergonomic comfort of workers & Ergonomic risk and posture comfort of worker crews [29; 65; 66]. \\ \cline{2-3}  & Efficiency of installation & Working efficiency of labor crews during the protection \\ \cline{2-3}  & Cost of protection system & The purchase or hire cost of protection system \\ \cline{2-3}  & Cost of system installation and removal & package [16; 29; 40]. \\ \cline{2-3}  & Maintenance and repair cost & Maintenance and repair cost of the equipment applied [11; 16]. \\ \hline \hline \end{tabular}
\end{table}