The two principal functions of interest groups are representation and education. For example, the National Telephone Cooperative Association (NTCA), which serves telecommunications cooperatives and companies in small towns and rural areas, provides its members "aggressive representation on Capitol Hill." It also conducts educational seminars, publishes a newsletter that tracks legislative and regulatory trends, and shares expertise on marketing strategies and new technology.
The representation function stems from the reason interest groups are created in the first place: Collective action is the most effective way of influencing policymaking and bringing issues to a large audience. Interest groups also serve as a watchdog, monitoring the actions of Congress, the courts, and the administration in the interest of their constituents. This work can include keeping track of the voting record of members of Congress and rating them on how well or how poorly they do on a particular issue.
Membership itself is important to success. More than 2.5 million people belong to the NRA, and 550,000 belong to the Sierra Club. Such numbers give the organizations immediate political clout as well as the resources to maintain a large staff, hire lobbyists, and conduct extensive public relations efforts.
Interest groups are concerned with maintaining and expanding their membership. Beyond political victories, they offer special member services that may include group health and life insurance, discounts on travel, and other similar programs. Direct mail, which is targeted to people likely to support the interest group based on level of income and education and their other affiliations, is a way of soliciting funds and building membership rolls. Such direct-mail campaigns can also put an issue before the public and help shape the political agenda of the country. All organizations appreciate, however, that some people benefit directly from what the organization does but will never become active participants or contribute money. This is known as the free-rider problem.
Interest groups educate both their own constituency and the public. Through their publications, the groups keep members abreast of the latest developments on the issues they care about. Business interest groups, particularly trade association, publish data and reports on their sector of the economy that are widely used. The American Petroleum Institute's triannual Basic Petroleum Data Book is an indispensable source on oil prices and production around the world. The League of Women Voters makes information available on ballot measures and the positions candidates take, and it organizes debates and issue forums. Because they have developed an expertise in a particular policy area, interest groups are often called on to testify before Congress irrespective of the position they might have on the legislation. Education is sometimes formal, as with the American Bar Association's Continuing Legal Education program, which provides attorneys with ongoing training.