## 3 Research Purpose and Methodology
### Questionnaire Survey  
A three-part online survey was designed to collect industry practitioners' perspectives. The first part briefly introduced the objectives of this survey, concepts of industrialized construction, and descriptions of each category of emerging technologies. The second part asked the respondents' company background and career profiles through single-choice questions, which included their company type, company annual revenue, occupation type, and working experience. Table 1 presents the options for each question, which can be regarded as the categories for different variables. The criteria for the data grouping are based on our preliminary research [13]. Each category was given a label for facilitating further analysis and processing. This part also collected respondents' experience on the industrialized construction projects. The third part of the survey asked the respondents to rate their current utilization levels of four technology types in the industrialized construction project separately using a four-point scale (i.e., 1 = none, 2 = low level, 3 = medium level, 4 = high level). We also clarified the specific criteria for each level: \"none\" means have never used this technology in the industrialized construction projects; \"low\" means have used this technology once or twice in the industrializedconstruction projects; \"medium\" means have used this technology in half of the industrialized projects; \"high\" means have used this technology in almost every industrialized project.  
The questionnaire survey was also translated into a Chinese version to overcome the language barriers in China. Finally, the survey was sent to the modular construction experts from the two countries separately to solicit feedback on the design, format, and content. The survey was then updated accordingly, and the final version was published on Qualtrics for distribution, which is a commonly used web-based survey tool.  
A snowball sampling method was utilized to distribute the survey. The snowball sampling method is a non-probability sampling technique in which the samples have traits that are rare to find. This is a sampling technique where the existing research participants recruit other participants for a test or study. For the survey distribution in the United States, initial respondents included manufacturers, designers, and project managers from several modular construction companies in Florida; in China, initial respondents included the practitioners from several modular construction companies in Jiangsu. Then, they were requested to answer the survey and distribute it to other knowledgeable participants they think appropriate within their country. The respondents were sent e-mails containing the hyperlinks to access the survey. The survey distribution lasted for two months, starting from August 9 to October 9, 2019. Approximately 500 questionnaires have been distributed in the United States, and 600 questionnaires have been distributed in China.  
The collected data were then preprocessed to filter out invalid responses. First, incomplete responses were removed. Then, since the questionnaire also contained questions asking the respondents' past experiences with industrialized construction. (e.g., Have you utilized any industrialized construction strategies? Which type of projects have you utilized industrialized construction strategies?), only responses of the respondents who had utilized any industrialized construction strategies or participated in any industrialized projects were regarded as valid.