In the United States, an interest group, sometimes also called a think tank, is an organization (usually non-profit) that seeks to represent its members' interests by lobbying, publishing, or other activities, and may publish information presented as expert analysis. The level of objectivity of this analysis varies widely with the institution but implies to non-expert readers at least some intellectual independence. Organizations referred to as interest groups are usually membership associations, whereas those called think tanks may only consist of paid employees who may sport titles such as "fellow". These groups vary widely in the independence (and therefore reliability) of their work.
Interest groups and think tanks may be distinguished from non-profit organizations that are engaged purely in charitable work and remain relatively apolitical, which might include food banks, for example. Many, but not all, interest groups (as well as think tanks) are active in trying to influence the public (if not overtly engaging in political lobbying), and their activities may include the publication of alleged expert analyses of a sort that might not actually make it into legitimate, peer-reviewed journals and thus must be called "research" only loosely.
As of 2024, many interest groups and think tanks are funded by wealthy private individuals who wish to promulgate their opinions to the public, and employees of these organizations work to reinforce the agenda of the funder. Many are little more than public relations fronts for a particular ideology. Because think tanks and interest groups generally make their publications available for free, many non-independent ones treat their output as if it is reliable news. Members of the public often do not understand the difference between objective think tanks and those which are pushing specific political agendas. Research laboratories, regardless of sponsorship, are usually not considered think tanks, which focus on publication of analyses. The output of these groups may even be branded as allegedly independent press, while not actually being independent from the agenda of the owners.
In order to evaluate how to regard information produced by a think tank, interest group, or non-profit group, it is necessary to find out who funds the group, and what the groups missions or goals are. If the owners, managers and funders are not known, and if there is no clear publicly available statement of mission or goal of the group (that seems accurate in terms of what they actually do), then (as with groups calling themselves press or "media"), the output of a group must be considered as possibly or even probably not reliable, and subject to everything from political axe-grinding to actual promulgation of conspiracy theories.