This chapter helps the students to identify the various control mechanisms for communication, to select the approach best suited to a specific communication campaign and to activate the evaluation of their communication initiatives. Controlling communication activities and, above all, assessing their effectiveness, are tasks which are often neglected by both private and public bodies. Analysing the effectiveness of communication campaigns and measures is the most frequent type of control, and usually the most important one for public bodies. The Synthetic model concerns a basic communication approach and, among other things, differentiates between the party communicating, the support, and the persons targeted. Based on the communication approach and the aspects outlined above, we can draw a list of criteria needed to assess the communication's effectiveness. The chapter discusses the impact of Public Relations (PR). PR aims to foster a good relationship with parties who are important to the organization.