An interest group is an organised association of people, organisations or institutions that shares a common interest, concern, identity or policy objective and seeks to influence public decisions without primarily seeking to become the government itself. Political science commonly defines interest groups in terms of organised collective efforts to influence government decision making or public policy.
Interest groups can be very broad or extremely specialised, ranging from organisations representing businesses, workers, farmers and professional occupations to groups concerned with environmental protection, civil rights, consumer interests, particular diseases, education, taxation, foreign policy or a single legislative proposal. Some are formal membership organisations with constitutions, staff and membership fees, while others are looser coalitions or temporary campaigns formed around a particular issue.
The defining feature is therefore not organisational size, legal status or ideology but organised political activity directed towards influencing outcomes. Interest groups differ from political parties because parties ordinarily seek to win elections and control government through their candidates, whereas interest groups normally seek to influence whoever holds political authority. OpenStax describes interest groups as organised collections of people seeking to influence political outcomes or public policy and distinguishes their usual issue focused objectives from the broader electoral objectives of political parties.
Interest groups can represent private interests, occupational interests, collective interests or claims framed as public interests. Business organisations may seek changes to taxation, regulation, trade policy or infrastructure spending; labour organisations may advocate employment protections, wages and working conditions; professional groups may seek changes affecting their occupation; and public interest groups may advocate policies intended to benefit wider populations rather than only their members.
Political scientists commonly distinguish economic groups from noneconomic groups, with economic groups including business, labour, agricultural and professional organisations and noneconomic groups including environmental, civil rights, ideological and single issue organisations. The boundary is not absolute because an organisation may pursue both material and normative objectives. A professional association, for example, can seek better conditions for its members while also arguing that its preferred regulation improves professional standards or public safety. Similarly, an environmental organisation may advocate a policy because it benefits its members, because it serves a conception of the public good, or because both considerations coincide.
Interest groups perform several political functions beyond direct lobbying. They aggregate preferences by bringing individuals with similar concerns together, articulate demands to policymakers, provide specialised information, monitor legislation and regulation, mobilise members, communicate with the public and sometimes help draft or analyse proposed policies. They can also encourage political participation by giving citizens opportunities to engage in politics between elections.
Activities can include contacting legislators, submitting evidence, providing testimony, meeting ministers or civil servants, publishing research, organising demonstrations, running public campaigns, communicating with journalists, producing policy briefings and encouraging supporters to contact elected representatives. OpenStax distinguishes inside lobbying, involving relationships and communications with government officials, from outside or grassroots lobbying, involving mobilisation of public pressure. Interest groups can therefore operate simultaneously inside formal political institutions and outside them through public communication and collective mobilisation.
The existence of interest groups is closely connected with collective action. Individuals may have a shared interest in a policy but still have limited incentives to contribute time, money or effort because they can potentially receive the benefits produced by others without participating themselves. This is commonly described as the free rider problem. Groups therefore use different mechanisms to encourage participation, including selective benefits, membership services, professional networking, information, social identity, reputational incentives and opportunities for political participation.
Interest groups can also arise after social or political disturbances create new demands or threats, an approach sometimes called disturbance theory. Pluralist theory views politics partly as competition among multiple organised interests, whereas transaction based approaches emphasise exchanges between organised interests and political decision makers and the advantages enjoyed by groups possessing resources, expertise or access. These theories do not provide one universally accepted explanation of interest groups, but they demonstrate that group formation and influence depend on organisation, incentives, resources and political opportunity structures.
Interest groups differ from political parties in purpose even though their activities frequently overlap. A political party normally seeks electoral office and attempts to assemble a sufficiently broad coalition to win representation and exercise governmental authority. An interest group can support candidates, provide political information, campaign during elections or encourage voters to support particular policies without becoming a political party. Its organisational identity is usually connected to a narrower set of interests or issues.
A party might need a platform covering taxation, healthcare, defence, education, foreign affairs and constitutional questions simultaneously, whereas an interest group can concentrate almost entirely on one issue or one constituency. This distinction is not absolute because some interest organisations become deeply involved in elections and some parties develop specialised policy networks, but their primary institutional purposes remain different. OpenStax explicitly identifies influencing policy as the main objective of interest groups and electing party members as the primary objective of political parties.
Interest groups can improve representation by bringing specialised knowledge and otherwise overlooked concerns into political debate, but their influence can also be distributed unequally. Organisations with large memberships, substantial financial resources, professional lobbying staff, technical expertise or privileged access to decision makers can have greater capacity to influence policy than groups with fewer resources. OpenStax notes that business and professional interests tend to be better resourced and that participation in interest groups can be socially unequal.
This creates a longstanding debate between pluralist and elite based interpretations of organised interests. From a pluralist perspective, numerous competing groups can prevent political power from being monopolised and can give different sections of society opportunities to organise. From a critical perspective, unequal resources may mean that formal freedom to organise does not produce equal political influence. Interest group politics therefore raises questions about representation, accountability, transparency, access, campaign finance, lobbying regulation and the relationship between organised power and democratic equality.
Interest groups can use several different channels of influence, and successful influence does not necessarily mean that a government simply adopts a group's stated position. A group may instead alter the wording of legislation, obtain an exemption, delay a proposal, secure funding, change regulatory implementation, shape the information available to officials or influence how an issue is framed in public debate. Expertise can be particularly important because legislators and administrators often require technical information about complex industries and social problems.
Groups may therefore provide research, statistical evidence, legal analysis, testimony and proposed legislative language. They can also monitor implementation after legislation has been passed. Their influence can operate at local, regional, national and international levels, depending on where decisions affecting their interests are made. In contemporary political systems, interest group activity is consequently part of a wider policy process involving elected representatives, bureaucracies, courts, media organisations, political parties, researchers and citizens rather than a single act of lobbying.
The term interest group is broad enough to encompass many organisations that are sometimes described more specifically as pressure groups, advocacy groups, trade associations, professional associations, civil society organisations or non governmental organisations. These terms overlap but are not exact synonyms. A pressure group usually emphasises attempts to exert political pressure, an advocacy group normally emphasises promoting a cause or policy position, a trade association represents organisations within an industry or sector, and a professional association represents people or institutions within a profession.
Civil society organisation is a broader category that can include many of these bodies. An NGO is another overlapping category whose meaning varies across legal and institutional contexts. The most useful general rule is that interest group describes a political function or organisational type centred on influencing policy, whereas the other terms can describe a group's sector, legal status, social location or characteristic method of activity.
