2–1. Randomized controlled trials
SECONDARY, RECRUITMENT
The randomized controlled trial of the sleep-improvement program analyzed in this paper was conducted among employees of a publicly traded Japanese manufacturing firm with more than 10,000 employees. The program was implemented over a six-month period from November 1, 2020, to the end of April 2021. Using a crossover RCT design, all subjects were randomly assigned to participate in one of the two periods (period 1: November to January, period 2: February to April). Of 215 participants who applied for the program, 157 were assigned to period 1 (treatment group) and 58 to period 2 (control group). The allocation to the two groups was unequal because of the firm’s decision to assign at least two-thirds of participants to the treatment group. Outcomes were assessed for the first period, with those assigned to period 2 serving as the control group.Note that our datasets are proprietary and obtained in a legally restricted manner under confidentiality agreements with the firm and therefore cannot be made publicly available. The research team was provided with the anonymized data after the firm obtained written consent from all participants for the data to be used for academic research purposes. Specifically, this project was an opt-in, rather than mandatory, recruitment process. The firm clearly stated that the data collected would be analyzed within the firm to improve employees’ sleep and that once the internal analysis was completed, the anonymized data would be made available to Waseda University for academic research. Employees were also given the option to refuse to provide their data, but all participants in the project gave their written consent to provide their data. The authors notified the Ethics Review Committee of Waseda University that the program would be implemented by the firm and that the data would be provided for secondary use after the firm conducted an internal evaluation. The committee issued a decision indicating that no ethical review was required.Participants were provided noncontact sensing devices from In addition, two seminars, which aimed to explain the app’s advice in detail and to provide knowledge about sleep hygiene, were held during the three-month program in period 1. However, participation in the seminar was voluntary, and to ensure fairness, the firm allowed not only the treatment group but also the control group to participate in the seminar. Since the data also identify the IDs of individuals who actually participated in the first and second seminars in both groups, the following analysis controls for seminar participation.