Workplace coaching is known to reduce stress and improve well-being. A significant factor that has been demonstrated to be efficacious in the reduction of stress in other areas of research is self-efficacy, which is a key concept in social learning theory. Coaching can enhance individuals' occupational self-efficacy. As occupational self-efficacy is related to stress and can be enhanced by coaching, we regard occupational self-efficacy as a promising mediating mechanism in coaching for reducing stress and increasing wellbeing. As coaches are costly, accessible and cost-effective alternative coaching formats, such as self-coaching, are advocated. However, whether these coaching formats can support the sources of occupational self-efficacy (mastery experience, social modeling, social persuasion and physical and emotional states) can be doubted. While mastery experience and emotional states might be triggered in self-coaching, social modeling and social persuasion both require another person, i.e. a coach. Therefore, we assume stronger mediation effects for coaching by coaches than for self-coaching.
The present study employs a longitudinal design, conducted over five measurement points, to assess the effectiveness of manualized stress coaching in self-coaching and coaching by coaches modalities on coachees' perception of stress and well-being. Furthermore, we investigated the general and differential mediation effect of occupational self-efficacy by using moderated longitudinal multi-level mediation analysis. In both coaching by coaches (N = 60) and self-coaching (N = 32), coachees completed online questionnaires before and after each session. The results show that the stress coaching intervention reduced coachees perception of stress and improved their well-being. Occupational self-efficacy partially mediates the impact of the intervention on stress and well-being in coaching by coaches, but not in self-coaching. These results indicate that self-coaching could rather supplement than substitute coaching by coaches. Theoretical and practical implications for different coaching formats are being discussed.