Interest groups are organizations that try to influence public policy by lobbying political decision-makers. There are two main types: public interest groups that represent broad public interests, and private interest groups that represent specific business sectors. Interest groups use both inside tactics like direct lobbying of officials, and outside tactics that mobilize public support. However, business and professional groups tend to have greater resources and stable relationships with government, giving them disproportionate influence over policy. Some argue this can lead to regulatory capture that undermines the public interest.