## 4 Discussion  
### Questionnaire Analysis of Likert Scale  
In this study, a questionnaire survey was conducted on the major risks encountered by personnel involved in Taiwanese construction projects by using a 5-point Likert scale (5 = \"Very important\", 4 = \"Important\", 3 = \"Neutral\", 2 = \"Low importance\", and 1 = \"Not at all important\"). The point range of the Likert scale can be increased to 9 points or reduced to 2 points. However, having an excessive number of scale points may increase the difficulty of completing the questionnaire for participants, and having an insufficient number of scale points may prevent the collected data from fully expressing the various degrees of participant intention. Given that 46 risk factors were rated in the questionnaire, a 5-point  
Figure 2: Flowchart of the research process. Likert scale was selected to ensure that the participants were not deterred from completing the questionnaire because of its lengthiness and to increase the validity of the questionnaire. The structure of the research sample for the valid questionnaire responses is described in the following text. First, with regard to occupation or the role in construction projects, 6.6%, 26.3%, 41.2% and 25.9% of the participants were project directors, construction site managers or personnel, personnel related to the construction project (planners, designers, and advisers), and project managers and supervisory personnel, respectively. Second, with regard to tenure in the construction industry, 14.0%, 29.2%, 21.4%, and 31.4% of the participants had 0-2, 2-10, 10-20, and more than 20 years of experience, respectively. Third, with regard to residential location, 26.7%, 5.8%, 66.3%, and 1.2% of the participants resided in northern Taiwan, central Taiwan, southern Taiwan, and eastern Taiwan, respectively. The construction auditing mechanism is a top-down quality management process. The government establishes the format of the inspection form, experts conduct on-site auditing, and project-related personnel implement construction and management operations. Therefore, 46 risk factors were selected from the five risk dimensions defined by experts and researchers. To identify the major risk factors, project-related and experienced personnel were invited to participate in the questionnaire survey. This approach ensured that the survey results were consistent with actual construction practices. The questionnaire content was closely related to the participants' professional work experience in Taiwan's construction industry. A total of 250 questionnaires were distributed, and 243 valid responses were retrieved; thus, the valid response rate was 97.2%. The obtained sample size satisfied the following requirement of [PERSON] and [PERSON] [51]: an effective sample size should be no less than 150, and the optimal sample size is over 200. Statistical analysis of the effective samples revealed that the data had a multivariate normal distribution [52]. The absolute values of the maximum kurtosis and maximum skewness were less than 7 and less than 2, respectively. Results indicated that each risk dimension had a reliability higher than 0.9; thus, the internal consistency coefficients (Cronbach's \(\alpha\)) of the dimensions were acceptable [53]. The reliability values (Table 2) obtained for the owner and supervisory unit dimension, contractor and labor dimension, material and equipment dimension, construction defects dimension, and relevant risks dimension were 0.98, 0.99, 0.95, 0.98, and 0.95, respectively. These results indicate that the adopted questionnaire has reliable internal consistency. The aforementioned reliability and distribution analysis results indicate that the adopted questionnaire is reasonable. Subsequently, a five-level histogram was mapped on the basis of the Likert scale scores and the 46 risk factors (Figure 3), and the top two-fifths of the risk factors (i.e., those with a score of >994) were selected as the major risk factors.