## 4 Results and Discussion  
### Descriptive Statistics and Data Ranking  
Identification of risk factors, associated with value and evaluation of their level of influence, plays a pivotal role in the project value created by the green building design. The risk factors were ranked based on their likelihood of impacting the project value created. Out of 300 professionals, 89 returned their fully completed questionnaire. This is an acceptable response rate (29.7%) as the typical response rate for a postal questionnaire survey in the construction industry is 20-30% [59]. The survey response revealed than 45% of the respondents were managers, 38% were engineers, and 17% were architects. Around 16% of the respondents were young, having 0-5 years of experience, 28% had experience ranged between 6 and 10, while the largest contribution was from senior respondents possessing more than 10 years of experience in the profession. Among the top 30 factors, the following discussion is limited to the top 3 and the bottom 10 risk factors. As the detailed statistical ranking results cannot be presented due to space limitations, a summary of the overall ranking and the ranking by each expert along with their years of experience is presented in Appendix B. The appendix shows that the average weighted mean for the risk factors varies from 3.33 to 4.24, with an overall mean of 3.78. The severity indices range within 66.52% to 84.72%. The highest-ranked factor is R35 (failure to identify low-value, long-lead-time items) with a mean of 4.24 and severity index of 84.72%. An overall examination of the first 30 ranked risk factors indicates that all of them have a minimum mean value of 3.81 (which is higher than the average overall mean of 3.78) and severity indices of 76.18%. This means that the first 30 ranked risk factors seem to be important as viewed by the respondents. They are namely: R1, R3, R5, R6, R7, R8, R9, R12, R17, R20, R21, R22, R33, R35, R36, R39, R44, R45, R49, R50, R51, R53, R54, R57, R63, R64, R65, and R66. Factor R64 (i.e., incorrect time estimate) has the second highest rank for the risk factors with a mean of 4.18 and a severity index of 83.60% and it is ranked as first out of 66 by the engineers and architects, and also by the experts with more than 10 years' experience. The managers ranked it fifth \begin{table}
\begin{tabular}{c c} \hline \hline
**Cronbach’s Alpha** & **Internal Consistency** \\ \hline \(>\)0.90 & Excellent \\ \hline
0.80–0.89 & Good \\ \hline
0.70–0.79 & Acceptable \\ \hline
0.60–0.69 & Questionable \\ \hline
0.50–0.59 & Poor \\ \hline \(<\)0.50 & Unacceptable \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Cronbach’s Alpha measures (source: [PERSON] [58]). out of 66, and the other rankings based on years of experience are: 0 to 5 and 6 to 10 years ranked it ninth and second out of 66 respectively. The third overall ranking was for R28 (i.e., poor design that may lead to higher operation costs), and the six groups of respondents also ranked it as one of their top 20 highest-ranked risk factors. R28 has a mean of 4.10, severity index of 82.02% and low coefficient of variation of 22.97%. The last 10 factors, amongst the top 30, have average weighted means for the risk factors that vary from 3.81 to 3.84 and severity indices that range between 76.18% and 76.85%.