Researchers are required to ensure that administrators and other key stakeholders have a clear understanding of their roles and responsibilities, and for the workers, to encourage them to sustain the autonomous activities for workplace improvement. et al., 1994; Theorell et al., 2001; Kawakami et al., 1997) and three randomized controlled trials (RCTs) (Kawakami et al, 2005 (Kawakami et al, & 2006 Takao et al 2007) . Studies were conducted in Japan, except for one from Sweden. Data were entered into and analyzed by STATA.