Defining interest groups Interest groups or special interest groups are any association of individual or organisations that on the basis of one or more shared concerns, attempt to influence public policy in its favour usually by lobbying1 members of the government. Interest groups may be classified according to their motivation: (i) economic, including individual corporations and business organisations; (ii) professional, including professional groups such as trade unions and farmers; (iii) public interest, including human rights groups, environmental groups, among others (Chari; Hogan; Murphy, 2010). For the purposes of this query, we will focus on the influence of economic interest groups.