Based on a randomized controlled trial applied to employees of a manufacturing company, this study examines the extent to which a corporate sleep program improves workers’ sleep health and productivity. In the three-month sleep improvement program, applicants were randomly divided into a treatment group and a control group, and the treatment group was provided with a noncontact sensing device to visualize their sleep. A smartphone app linked to the device notified them of their sleep data every morning and presented them with advice on behavioral changes to improve their sleep on a weekly basis. The results of the analysis revealed the following. First, even after controlling for factors that may cause sleep disturbances and nocturnal awakenings, such as increased workload and the number of days spent working from home during the measurement period, the treatment group showed improved sleep after the program compared to the control group. Second, the treatment group showed statistically significant improvement in presenteeism (productivity). The effect size on presenteeism through sleep improvement was similar regardless of the estimation method used (i.e., ANCOVA estimator of ATT and two 2SLS methods were performed). In particular, we confirmed that productivity was restored through sleep improvement for the participants who diligently engaged in the program. These results suggest that promoting sleep health using information technology can improve sleep deficiency and restore productivity.

The Elderly Employment Stabilization Law, revised in 2006, helped the government increase elderly employment. While there has been much debate on whether the reemployment of elderly workers has substituted for or increased the employment of young workers, little attention has been paid to the potential peer effects of the former group on the latter's productivity and other outcomes in the workplace. There might be knowledge spillovers from elderly workers to peers (positive peer effects) or the presence of unmotivated elderly workers lowering the morale of their coworkers (negative peer effects). In this paper, we investigate such peer effects from exposure to elderly workers using the employee satisfaction survey of a Japanese firm. We show that, on average, elderly workers do not have significant peer effects on coworkers’ satisfaction. However, the effects are heterogeneous depending on the ability of elderly workers as measured by their wages, and the age and job levels of their peers. Namely, nonmanagerial workers, particularly those in their 50s, are more satisfied and coworkers in their 30s and 40s receive more training when they work with elderly workers. The positive effects are significant when the focal elderly workers come from other units rather than when they stay in the same units implying that the sharing of broad experience might mediate the effect. In contrast, the presence of elderly workers makes first-line managers feel that there is poor communication in the workplace.