Effect of intervention on productivity through improved sleep (2SLS).
depression, insomnia, depressed
REGRESSION
(Notes) 1. Robust standard errors in parentheses.2. ***, **, and * indicate statistical significance at the 1%, 5%, and 10% levels.3. The variables described in section 2.2.4 are used as control variables in the estimation but are omitted from the table.4. Regarding Note that the purpose of this paper is to examine the relationship between sleep improvement and productivity in the general workforce, rather than in patients with insomnia. Therefore, we did not set any special criteria for recruiting subjects within the company but recruited a wide range of workers who were interested in improving their sleep health. However, we must be aware of the possibility that some of the applicants may have had insomnia or depression, which could substantially affect the effectiveness of the sleep hygiene program. To prevent such cases from affecting our results significantly, we also ran the same regression analysis with a subsample, excluding observations based on several of the criteria (those who had mentioned “sleepless,” “need improvement in physical condition,” or “Feeling depressed almost every day”) as a robustness check. We obtained similar results to those reported in this paper even after excluding those observations.