3.1.1. Data Collection

A questionnaire is used to collect data. The questionnaire has two parts. The first part is input variables, which have been shown in Figure 1. The second part is output variables, i.e., the five common safety behaviors. The sources of those indicators measuring these variables and the measures to ensure the questionnaire is self-contained and self-sufficient are recorded in Shen's work [41]. The sources of the indicators for each construct are also recorded in Shen's work [41]. The details of those input and output indicators are shown in Table A1 (Appendix A) and Table A2 (Appendix A), respectively.

The target population is Hong Kong construction personnel who are generally in three categories, i.e., contractor, consultant, and client. The contractor category includes management staff and direct laborers from main contractors and subcontractors. The consultant category covers engineers, architects, and quantity surveyors. The client category comprises both the public and private sectors. The target population size is unknown. The research team sets the confidence level at 90%, the margin of error at ±5%, and the population proportion at 50%. Using Cochran's formula, the required sample size should be no less than 273. In order to secure sufficient, valid, and representative responses, the research team constructs a sampling frame consisting of construction personnel from local construction trade associations, professional bodies, governmental agencies, and property developers. Then, the research team sends hard-copy questionnaires to a random sample of 2996 construction personnel from the sampling frame. After two rounds of administration, the research team secures 292 valid responses. Non-response bias is not an issue [10].
