This paper investigates how employees respond to evidence about their organization’s performance in achieving its mission. In a randomized field experiment with the Ministry of Public Health of Guinea-Bissau, I provide front-line health workers with evidence of their program’s effectiveness in improving local health indicators. The intervention significantly enhanced healthcare service delivery performance, with treated workers providing 39 percent more healthcare time to recipients compared to the control group six months post-intervention. The intervention is particularly effective in correcting over-optimistic prior beliefs about the status of health indicators. These results highlight the potential for organizations to harness performance evidence to enhance workers’ efforts.