## 3 Method and Data Presentation  
Figure 1 presents the research methodology. The literature search indicated that the use of questionnaire survey technique was appropriate in collecting professional views on critical factors in previous construction management studies [39; 40]. Thus, a questionnaire survey was performed to investigate the 47 hindrances' influence on BIM implementation in the Singapore construction industry. The questionnaire was designed on the basis of the above literature review and refined according to the comments from five BIM experts who were interviewed face-to-face in a pilot study. All the experts, who were working for large firms and possessed at least three years' experience in implementing BIM in Singapore, were selected to pretest the questionnaire. The final questionnaire collected general information of respondents, and requested them to rate each hindrance's influence on BIM implementation. The ratings should be made regarding one of their ongoing or recently-completed building projects. A five-point Likert scale (1 = very insignificant; 2 = insignificant; 3 = neutral; 4 = significant; 5 = very significant) was used. [PERSON] [41] found that a human usually can hold \"seven plus or minus two\" objects in working memory. In a one-dimensional absolute-judgment task, a person is presented with a number of stimuli and responds to each stimulus with a corresponding response. Performance is nearly perfect up to five or six stimuli but declines as the number is increased. Thus, to make it convenient for the respondents to judge, the five-point scale was adopted in this paper, which has been widely used in previous studies related to construction management [42; 43; 44; 45]. Figure 1: Research methodology. The population was comprised of all the organizations that were operating in the Singapore construction industry. The sampling frame consisted of the BCA, the Urban Redevelopment Authority, the Housing and Development Board (HDB), the building developers registered with the Real Estate Developers' Association of Singapore, the architectural consultancy firms registered with the Singapore Institute of Architects, the structural and MEP consultancy firms registered with the Association of Consulting Engineers Singapore, the contractors registered with the BCA, and the facility management firms registered with the Association of Property and Facility Managers. Among the contractors, it was considered logical to select only the large ones because they tend to have adequate resources for BIM implementation. Since there was a sampling frame, a probability sample should be adopted. Simple random sampling was used in the data collection because each organization was as likely to be drawn as the others. Finally, the questionnaires were sent to 692 organizations via emails or handed to them personally. It was considered appropriate that 87 completed questionnaires were received based on willingness to participate in this study [46]. The response rate of 12.57% was acceptable because it fell within the general response rate of 10-15% for Singapore surveys [39]. The profile of the 87 respondents is shown in Table 2. The 14 organizations in the \"others\" category included the BCA, the HDB, developers, precasters, and other consultancy firms such as multidisciplinary consultancy firms and a BIM consultancy firm. Thus, the responding organizations could represent major BIM implementers in the local construction value chain. Moreover, because BIM implementation had been mandated in Singapore since July 2015, it was reasonable that under half (42.53%) had over three years' BIM implementation experience. In addition, after the survey was performed, five BIM experts who had participated in the survey and were experienced in BIM implementation in the Singapore construction industry were contacted for personal interviews. During which, they were presented with the results obtained from the survey. They commented that the findings were in agreement with what they expected.