## 3 Research Methodology
### Phase One: Identify the Significant Groups  
This phase aims to distinguish the significant groups from the insignificant groups. The following steps were performed to achieve the purpose of the first stage.  
Step 1: Ten models were created; each model consisted of one _exogenous_ group (ER, DR, MR, CR, SCR, EQR, PGRE, ECR, OGR, or SR) and one _indigenous_ group (time or cost).  
Step 2: The outer model was assessed for each model regarding construct and reliability validity.  
Step 3: If the _exogenous_ group of the model was satisfied, especially for the CR and AVE, the groups were considered significant. Otherwise, the group was considered insignificant.  
Step 4: The hypothesis relationship of each model was examined.  
These steps are depicted in Figure 3.  
The CR and AVE of the _exogenous_ group depended on the outer loading of its factors. They were assessed several times by studying the omission of one or more factors that had a lower outer loading on the CR and AVE of the group. These steps resemble the studies conducted by [PERSON] [36] and [PERSON] and [PERSON] [42], which can be referred to for more information.  
Tables 4 and 5 show the CMR and AVE of ten models for the time and cost of installing a pile in the sand, respectively. ER and ECR are insignificant risk groups for the time and cost of pile installation in sand. However, DR, CR, EQR, and SR are significant risk groups for time and cost. In addition, MR and OGR are significant risk groups for time and cost, respectively. At the same time, Tables 6 and 7 show the CMR and AVE of ten models for time and cost of installing a pile in rock, respectively. The insignificant risk groups for the time and cost of installing a pile in rock are ER, MR, and PGR.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Model** & **Group** & **CMR** & **AVE** & \(p\)**-Value** & **Significant Factors** \\ \hline Model 1 & ER & 0.51 & 0.50 & 0.319 & ER1, ER2 \\ Model 2 & **DR** & **0.7** & **0.54** & **0.0593** & **DR4, DR5** \\ Model 3 & MR & 0.67 & 0.52 & 0.001 & MR1, MR2 \\ Model 4 & **CR** & **0.71** & **0.56** & **0.007** & **CR4, CR6** \\ Model 5 & **SCR** & **0.69** & **0.52** & **0.131** & **SCR1, SCR2** \\ Model 6 & **EQR** & **0.69** & **0.52** & **0.067** & **EQR2, EQR** \\ Model 7 & PGR & 0.22 & 0.46 & 0.56 & PGR1, PGR2 \\ Model 8 & ECR & 0.67 & 0.53 & 0.30 & ECR5, ECR6 \\ Model 9 & **OGR** & **0.69** & **0.53** & **0.014** & **OGR2, OGR3** \\ Model 10 & **SR** & **0.67** & **0.51** & **0.004** & **SR1, SR2** \\ \hline \hline \end{tabular}
\end{table}
Table 4: Results of the first phase on time needed to install a pile in sand.  
Figure 3: Flow chart of the first stage.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Group** & **CMR** & **AVE** & \(p\)**-Value** & **Significant Factors** \\ \hline ER & 0.65 & 0.55 & 0.687 & ER1, ER2 \\
**DR** & **0.7** & **0.55** & **0.277** & **DR2, DR4** \\
**MR** & **0.69** & **0.53** & **0.613** & **MR1, MR3** \\ CR & **0.72** & **0.58** & **0.015** & **CR3, CR6** \\ SCR & 0.59 & 0.51 & 0.244 & SCR1, SCR2 \\
**EAR** & **0.68** & **0.53** & **0.05** & **EQR4, EQ6** \\
**PGR** & **0.70** & **0.55** & **0.067** & **PGR1, PGR2** \\ ECR & 0.66 & 0.51 & 0.04 & ECR2, ECR4 \\ OGR & 0.68 & 0.52 & 0.001 & OGR2, OCR2 \\
**SR** & **0.71** & **0.55** & **0.065** & **SR4, SR5** \\ \hline \hline \end{tabular}
\end{table}
Table 5: Results of the first phase on the cost of installing a pile in sand.