Research says it all:

1. Employees will stay if they have a good relationship and open communication with their immediate boss. (HRI Institute, 2001)
2. Employees typically see the organization as they see their supervisor. (Tross & Egermann, 2005)
3. As the job market improves and people find more employment alternatives, leaders will need to put more effort into retaining talent. (Gantz Wiley Research, 2004)
4. The front-line leader is of critical importance in building engagement. (Gopal, 2004)
5. The root of employee disengagement is poor management. (Gopal, 2003)
6. Employees need bosses who care about them, and will help them achieve their goals. (Human Resource Institute, 2004)
7. Much of engagement work must be done by first-line supervisors. (Bates, 2004)
8. Employees who believe that the supervisor values their contributions and cares about their well-being believe that the organization on the whole supports them more, which in turn relates to decreased turnover. (Eisenberger et al., 2001)

References:

1. Human Resource Institute (2001). "Loyalty and Commitment: A survey on Attracting and Retaining Workers."
2. Tross, S. & Egermann, M. (2004) "Employee-Manager Relationship Duration: Effects on Perceived Supervisor Career Development Support & Voluntary Turnover." Society for Industrial and Organizational Psychology Annual Conference, April.
3. Gantz Wiley Research (2004), "WorkTrends 2004."
4. Gopal. A. (2004). "Flawed Assumptions Can Defeat Your Business," Gallup Management Journal, April 8.
5. Gopal, A. (2003), "Disengaged Employees Cost Singapore $4.9 billion," Gallup Management Journal, October 9.
6. Human Resource Institute (2004). "Reengaging the Workforce," TrendWatcher, Issue 211, May 7.
7. Bates, S. (2004). "Getting Engaged." HR Magazine, 49(2).
8. Eisenberger, R., Armeli, S., Rexwinkel, B., Lynch, P.D., & Rhoades, L. (2001). Reciprocation of perceived organizational support. Journal of Applied Psychology, 86. 42-51.