In this chapter, we review the development of the activation concept in Swedish sickness insurance during the 2000s, by analyzing how it is conceptualized in government reports and translated into policy and practice. At different times, policy has been informed by different types of knowledge, where the conceptualization of activation has developed from focusing on individual responsibility for rehabilitation and promoting return to work through restricting access to benefits, towards a systems perspective, where return to work is considered a multistakeholder endeavor. We offer a critical analysis of the use of evidence in policy development and its practical consequences.