It is important that accident should be prevented at the first time by first-line supervisors if there are any unsafe conditions in construction site; therefore, first-line supervisors need to have a good hazard risk perception. The purpose of this study was to develop an instrument using Signal Detection Theory (SDT) to measure hazard risk perceptions of people in construction site.
The subjects were 140 senior students (33 females and 107 males) in occupation hazard and safety department. Four tests (Safety Attitude, Hazard Risk Cognition, Safety Knowledge, and Construction Site Hazard Risk Perception) were designed in this study.
The results showed that the first three hazard risk perceptions of the major injures in construction site were “falling objects”, “falls”, and “stab, cut, abrasion”. Two-way ANOVA showed that the factors of the gender, age, and years of working did not affect the hazard risk perceptions when the subjects observed the unsafe pictures of the construction site. Six types of major injuries in construction sites were categories in different risk perception levels. The types of injuries in “collapse”, “falls”, “fallen objects” , and “stab, cut, abrasion” were categories in first hazard risk perception level; the second hazard risk perception level was “fires and explosions”, the lowest level was “electric shocks”.
The results of the measure in signal detection, the sensitivity value（d’）of the male and female were 1.284 and 1.152. Two-way ANOVA of the sensitivity value（d’) showed significant interaction between gender and working years. The measure of the signal detection threshold（β）of the male and female were 0.442 and 0.532, meaning both were categories in “non-conservative”. The value of the ROC analysis in hazard risk perception of AUC was 0.767, representing subjects’ signal detection accuracy in fair level.