4–5. Economic return to sleep improvement programs
sleep-related behaviors
In section 4–4, we measured the effects on productivity through three pathways: average effects on the treatment group, local average treatment effects of diligent participants, and indirect effects through sleep improvement. Based on those estimators, we evaluated the economic return to sleep improvement programs using the total WLQ score. Although we should look at the net return on investment, the total cost of the sleep improvement program was not disclosed to us by the firm, so we only evaluated the economic benefit.The following assumptions are made in our calculation.The range of change in the overall WLQ score equals the rate of change in productivity.The average productivity per person per year is 8 million yen (approximately 60,000 US dollars).For the 112 participants in the treatment group who responded to the WLQ, the estimated effect of the intervention continued for one year.The first assumption is based on our understanding that the WLQ was originally designed to measure the value of productivity loss (Lerner et al. [According to Next, the local average treatment effect (LATE) of diligent participation in Finally, the coefficient of sleep improvement (i.e., endogenous variable in 2SLS) in The most uncertain of our assumptions is the third assumption, the duration of the intervention effect. The Hawthorne effect may have exaggerated the short-term effect of the program, and the improved sleep-related behaviors and productivity gains may be reversed in a few months. Conversely, there is also a possibility that participants who realized the importance of sleep may continue to take steps to improve their sleep, and the effects may last for more than a year.