Father's 'Parental Leave Training' Transforms Families: Increased Paternal Involvement Enables Mothers to Work Longer

Results of the EVIDENCE STUDIO Project and Commissioned Research with the University of Tokyo: A Randomized Controlled Trial (RCT) Involving Over 1,200 Participants Across Four Organizations

EVIDENCE STUDIO (a general incorporated association) operates under the key principle of 'improving society through evidence,' primarily in the field of social security. In collaboration with member companies, local government leaders, and founding members, the organization identified key themes and commissioned research to Professor Shintaro Yamaguchi (Graduate School of Economics, The University of Tokyo). EVIDENCE STUDIO managed funding, coordinated participating organizations, planned and operated the training program, and oversaw the entire project, conducting a large-scale randomized controlled trial (RCT) involving over 1,200 male employees across four Japanese organizations.

The results revealed that a two-hour workplace training session for fathers not only increased their own involvement in childcare but also led to an increase in working hours for mothers who did not attend the training.

Key Findings from the Study

- A two-hour workplace training for fathers increased weekend childcare time by approximately one hour per day (a 16% increase).

- Changes in household role distribution led to a 3.6-hour weekly increase in working hours for mothers who did not attend the training (an 18% increase).

- Effects were particularly pronounced in households with children under five, where childcare time increased by up to 2.3 hours per day.

- The proportion of participants who independently researched parental leave policies after the training increased by 16 percentage points.

- Merely informing participants that 'colleagues actually support parental leave' changed perceptions but did not translate into behavioral change.

EVIDENCE STUDIO's Role in the Project

This study was consistently led by EVIDENCE STUDIO, which took charge from problem identification through implementation (research was outsourced) and management.

- Problem Identification and Theme Selection

Through repeated discussions with member companies, local government leaders, and founding members, 'promoting male involvement in childcare' was identified as a priority social issue.

- Research Funding

Provided research funding to the University of Tokyo as a commissioned study, ensuring research independence and quality.

- Coordination and Formation of Participating Organizations

Recruited two private companies and two local government bodies to collaborate, establishing a coordinated framework.

- Planning and Operation of the Training Program

Collaborated with the NPO Fathering Japan to implement the training program.

- Overall Project Management

Led centralized efforts including ethical review, pre-registration with the AEA RCT Registry (AEARCTR-0012315), and progress monitoring.

Research Background

Japan offers one of the most generous parental leave systems in the world, allowing fathers up to 12 months of leave. However, as of 2023, only about 30% of fathers took parental leave.

Many fathers cite 'workplace culture' as the reason for not taking leave, suggesting that policy improvements alone are insufficient to drive behavioral change. Meanwhile, large-scale experimental studies verifying the effectiveness of workplace interventions to promote male participation in childcare and housework are extremely rare worldwide.

EVIDENCE STUDIO focused on this issue, posing the question: 'Can behavior change be achieved by directly influencing workplace norms and awareness, rather than relying solely on policies?' In collaboration with the University of Tokyo's research team, they undertook scientific verification.

Research Methodology

From August 2023 to March 2024, an experiment was conducted across four organizations—two private companies and two local government bodies—with over 1,200 male employees. Eighty workplaces were randomly divided into two groups to compare the effects of the training.

Male instructors delivered lectures on balancing childcare involvement with career development, and managers were also taught how to support subordinates taking parental leave. Additionally, a separate intervention provided information stating that 'colleagues are actually supportive of parental leave,' to examine whether correcting perceptions would lead to behavioral change.

Detailed Results

- Effect of the Training

Fathers who received the training increased their weekend childcare time by approximately one hour per day. It was also confirmed that overall family time spent with children increased (the increase in fathers' childcare time did not come at the expense of mothers' childcare time).

Changes were also observed in mothers who did not attend the training. Their weekly working hours increased by 3.6 hours, and their housework time decreased. This suggests that changes in fathers' behavior led to a reassessment of household role distribution.

- Information Provision Alone Did Not Change Behavior

In reality, 86% of colleagues supported 'male employees taking parental leave.' However, only 54% of participants expected others to hold this view, revealing that despite majority support, most felt it was difficult to speak up in the workplace.

While the intervention successfully corrected this perception gap, no changes were observed in intentions ('would you like to take parental leave in the future?') or actual behavior. Simply knowing that 'others support it' is insufficient; direct interventions targeting attitudes and awareness are necessary.

- Policy and Social Implications

- In addition to legal systems and economic support, combining workplace awareness reform is crucial. Even a two-hour training can drive real behavioral change.

- The ripple effects of paternal childcare involvement (such as mothers continuing employment) occur within households. To promote widespread adoption, public support systems must be established, not left solely to companies.

- Merely stating 'everyone supports it' is insufficient. A comprehensive approach with organizational backing is required.

In Japan, where addressing the declining birthrate is urgent, promoting male involvement in childcare supports mothers' continued employment and enhances the quality of life for all parenting households. This study demonstrates that low-cost, easily implementable workplace training can be an effective means to achieve this goal.

Research and Publication Information

Paper Title: Workplace Norms and Paternal Involvement in Childcare

Journal: University of Tokyo CREPE Discussion Paper (CREPEDP-202)

Authors: Mari Tanaka, Hiroko Okudaira, Mariko Sakka, Shintaro Yamaguchi

URL: https://www.crepe.e.u-tokyo.ac.jp/results/2026/crepedp202.html

Research Funding: JSPS Grant-in-Aid for Scientific Research (A) (JP23H00045), EVIDENCE STUDIO General Incorporated Association

Research Team

University of Tokyo

Professor Shintaro Yamaguchi (Graduate School of Economics)

Associate Professor Mari Tanaka (Graduate School of Economics)

Doshisha University

Associate Professor Hiroko Okudaira (Graduate School of Business)

University of Tsukuba

Associate Professor Mariko Sakka (Faculty of Medicine and Medical Sciences)

Contact

For inquiries regarding this research or activities, please contact EVIDENCE STUDIO General Incorporated Association.