Types of think tanks

Think tanks represent a variety of ideological perspectives. Some think tanks, such as the Heritage Foundation, are clearly aligned with conservative causes. Others, especially those focused on social and environmental reforms, such as the Tellus Institute, are viewed as clearly liberal. Still others, such as the Cato Institute, promote libertarian social and economic reforms.

A new trend, resulting from globalization, is collaboration between think tanks across continents.

Criticism

Critics such as Ralph Nader have suggested that, because of the private nature of the funding of some think tanks, their results are biased to a varying degree. Some argue that members will be inclined to promote or publish only those results which ensure the continued flow of funds from private donors.

In some cases, corporate interests have found it useful to create "think tanks." For example, The Advancement of Sound Science Coalition was formed in the mid 1990s to dispute research finding a link between second-hand smoke and cancer. According to an internal memo from Philip Morris, "the credibility of the EPA [Environmental Protection Agency] is defeatable, but not on the basis of ETS (environmental tobacco smoke) alone. It must be part of a larger mosaic that concentrates all the EPA's enemies against it at one time."