## 4 The Application of the Proposed Model
### Case Study
#### 4.1.1 Application of the ANP Method  
Based on current literature and expert investigations, a hierarchy of criteria and sub-criteria was established. The ANP method is a powerful and effective tool to identify the importance of different criteria and determine the criterion weights that are critical to the evaluation of PPE performance. The advantage of applying the ANP method in this research is to consider the relationship between different criteria and determine the weights of criteria and sub-criteria based on the hierarchical structure for the multi-criteria assessment. In this research, three PPE alternative plans were provided for the construction project, and the decision-makers needed to select the best one among them. In order to make the most reasonable decision, 23 experienced experts were invited to participate in group decision making to evaluate the potential PPE plans. Given that the demographic factors could influence the safety behaviors of planners during PPE selection, the participants with varying ages, genders, and working experiences were involved in the decision-making process. Therefore, the developed method is able to comprehensively analyze the assessment results from multiple individuals with different preferences, which leads to the most compromising assessment results obtained from participants with various backgrounds. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Configurations** & **A1** & **A2** & **A3** \\ \hline Safety helmet & C30 hard helmet & 911C hard helmet & S61 hard helmet \\ Eye protectors & RX Safety Glasses & 3M safety glasses & SolidWork Safety Goggles \\ Ear protector & Earplugs & Earmuffs & Earplugs \\ Mark and respirator & 3M 8511 N95 & 3M 8210 N95 & 3M 8210 N95 \\ Protective gloves & Ironclad Tuff Chix & GRX Palmwick Gloves & EXOTTactical Operator \\  & & Impact Gloves \\ Safety belt & Guardian Series Construction & Super Anchor Deluxe Tool & Super Anchor Deluxe Harness \\ Safety footwear & Thorogood work boot & Ariat work boot & Carolina footwear \\ Protective clothing & Wrangler & Carhartt & Helly Hansen \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Configurations for PPE plan alternatives. The specific demographics of the participating respondents are illustrated in Table 5, such as their age, gender, and working experiences in the construction field. In the investigation, an expert group, which comprised four superintendents, three project managers, four site engineers, and three workers, was selected to participate in the questionnaire process. Among the expert respondents, the majority (40%) of the participants were between 41 and 50 years old, and 52% were male. Most of the respondents had a rich working experience in the construction field, whereas 26.67% and 33.33% of the participants had 10-15 years and 15-20 years of working experience, respectively. Meanwhile, 20% of the participants had more than 20 years of working experience. Based on the judgments of the participants, pairwise comparisons were made to assess the relative importance of different criteria. After the feedback response of pairwise comparisons was received, the ANP method was adopted to determine the weight of the main criteria and sub-criteria. Based on the criteria hierarchy, the ANP network was established. The network analysis for criteria weighting is illustrated in Figure 5. Using the 9-point scaling approach, the average assessment for each criterion was calculated using the Super Decisions software (version 3.2.0). Super decisions Software is a software tool that implements the analytic network process (ANP) through criteria comparison assessments and is capable of conducting a priority calculation process based on the dependencies and feedback among the related criteria. The software determines and outputs the priority weights of the involved criteria through a semi-automatic path. In this assessment process, 1 represents \"equal importance\", while 9 represents \"absolute importance\".