1. Introduction
work-related injuries, sleep deficiency
VEHICLE ACCIDENT, BRADLEY, SAID
In this modern society, it is said that a significant proportion of people have problems with sleep, and sleep deprivation or sleep deficiency has become a global concern. For example, according to the Sleep Foundation [A number of previous sleep studies have shown that problems with sleep can cause serious impairments in daytime performance, such as motor vehicle accidents or work-related injuries (Leger et al. [However, since most previous studies described above were based on cross-sectional data, identifying the causality between sleep and productivity is still a challenge. Just as there is an endogeneity problem in identifying the impact of sleep on health, the relationship between sleep and productivity is not clear (see, for example, Anderson and Bradley [