Think tanks – also called policy institutes or research institutes – are interest groups that conduct research and generate knowledge to advocate on all sorts of topics potentially subject to political regulation. Think tanks can be categorized into many different types depending on their ideological stance, sources of funding, topics addressed and working routines. Some advocacy organizations that are not research institutes may also produce knowledge and be considered think tanks in their fields. This is the case of some green NGOs, whose reports on, for instance, the political economy of global warming or alternative climate solutions, are very influential.

In all cases, these actors are largely involved in the use of communication strategies and tools. For this reason, a multidisciplinary approach that includes the perspective of communications in its widest sense (critical public relations, public affairs, marketing, the political economy of communication and public relations) has the potential to be more effective in studying such groups.