## 4 Results and Discussion  
### Ranking of Hindrances to BIM Implementation  
The Cronbach's alpha coefficient was 0.974, much higher than the threshold of 0.70 [47]. Thus, the data collected in this study had high reliability. The ranking of the 47 hindrances to BIM implementation in the Singapore construction industry was shown in Table 3. A few methods were adopted to identify the critical factors when Likert scale data were collected in previous studies, but none of them was established as a standardized method. The threshold value was also not determined. [PERSON] et al. [48] recognized all the factors that were deemed critical in previous studies. No cutoff point was established in this said study. [PERSON] and [PERSON] [49] set a cutoff value of 4 because it represented \"significant\" in the five-point scale in this study. [PERSON] and [PERSON] [50] used the middle value of the Likert scale as the threshold. [PERSON] et al. [51] and [PERSON] et al. [43] chose the factors with normalized values of 0.50 and above as the critical factors. [PERSON] et al. [52] selected the factors with mean values exceeding the total mean value of the data as the critical factors.  
In this study, the mean scores of the 47 hindrances to BIM implementation in Singapore were normalized, as shown in Table 3. The hindrances that obtained normalized values of 0.50 or above were recognized as critical ones. The results implied that out of the 47 factors, 21 were critical in hindering BIM implementation in building projects in Singapore. Besides, all the mean scores (3.494 and above) of the 21 critical hindrances exceeded 3.451 which was the total mean value of all the 47 hindrances. However, the 22 nd hindrance (H37) obtained a mean score (3.448) below this total mean value. Thus, the results of applying the \"comparing mean scores with the total mean value\" method supported the normalization method which was adopted in this study. Among the critical hindrances, \"need for all key stakeholders to be on board to exchange information\" (H12) was ranked top. This result echoed [PERSON] et al. [53], which found that early involvement of the contractors to share expertise and information upfront is key to creating optimal design models early in a building project. In the post-survey interviews, the experts mentioned that in Singapore downstream parties were generally not involved upfront, and also suggested that BIM implementation would be efficient if the entire team (the owner, the designers, the contractors, and the facility manager) could actively participate from the beginning of the design stage. Indeed, lots of details need to be developed by specialist contractors who, however, usually used the traditional approach in design detailing. Based on the ranking of the critical hindrances in Table 3, the practitioners would have a clear knowledge of the areas of activities of BIM implementation deserving more attention, and establish resources allocation priorities accordingly.  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline
**Code** & **Mean** & **Rank** & **Normalization \({}^{\star}\)** & **Code** & **Mean** & **Rank** & **Normalization \({}^{\star}\)** & **Code** & **Mean** & **Rank** & **Normalization \({}^{\star}\)** \\ \hline H01 & 3.644 & 8 & 0.782 & H17 & 3.161 & 46 & 0.018 & H33 & 3.540 & 13 & 0.618 \\ H02 & 3.494 & 20 & 0.545 & H18 & 3.184