Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)


Political Science


Building on interest group and congressional committee literature, the interest group impact theory is created to explicate the role of interest groups in congressional committee hearings. This theory applies not only to the influence interest groups have in congressional hearings, but also to the access given to them to be able to participate. The theory maintains that interest groups are necessary to legislators in this capacity since they provide valuable information relating to politics, elections and policy. Resource rich interest groups with visibility as experts in a policy area are expected to be given more access and influence particularly to committees that are more balanced in terms of partisanship, ideology and leadership experience.

Two statistical models test the interest group impact theory, one looks at the access granted to interest groups to participate in congressional hearings and the other at the influence wielded by the testimony they give in those hearings. A unique data set is developed for each model. The access dataset consists of attempts by interest groups to testify before House committees during the 105th, 106th, 107th and 108th sessions of Congress, and consists of data compiled from the Lobbying Disclosure database. A unique dataset of coded congressional hearing testimony submitted by interest groups from six committees and their subcommittees during the 103rd, 106th and 108th Congress was created for the influence model.

The research results indicate partial support for the interest group impact theory. Interest group resources increase the likelihood of an interest group access. However, any advantages those resources are in gaining access to congressional hearings, they do not influence the likelihood of the committee adopting the recommendations given in testimony. What do matter are characteristics relating to the committee such as ideology, partisanship and the experience of the chairs. Interest groups do attempt make real recommendations in hearing testimony although they see little success in influencing bill markups.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.