The Participation Act was introduced on the 1th of January 2015, in order to create a more inclusive labor market in The Netherlands. The actual execution of the Act is decentralized. Municipalities are responsible for encouraging firms to create labor opportunities for vulnerable groups. Municipalities adopt different mean and instruments to do so, consequently there exist a variety of municipal policies (Sociaal en Cultureel Planbureau, 2019). Currently, there is no public readily available CBS data on the ‘inclusiveness’ of firms among municipalities, which makes it hard to assess the effectiveness of municipal policies and derive best practices. However, this data is key, in exploring why one municipal policy is more effective in stumulating inclusion of vulnerable grous, than another. Specifically, this study aims to answer the following research question: “Which/ what factors underlying differences in municipal inclusive policies explain differences in inclusion rates of vulnerable groups among firms?”. We develop and test a theoretical model of how differences in municipal policies and their effects come about by connecting institutional- with policy diffusion theory. Empirically we aim to examine inclusive behavior of firms among all 380 municipalities in The Netherlands among the period between 2014 and 2019. We will use a variety of methods including machine learning. We intend to make several contributions to theory and practice- i.e. by showing how content of policies come about and effect inclusiveness.