Use of Bellwether Samples to Enhance Pre-Election Poll Predictions: Science and Art

In this article, the authors document a new pre-election polling method that combines traditional probability sampling in statewide polls with sampling of bellwether districts. Against the backdrop of the 2008 presidential primary in New Hampshire, the authors explain how the Suffolk University/WHDH predictions, using additional bellwether tests, were closer than most other polls in correctly calling the Democratic primary race. Thus, the contributions in this article are twofold. The authors offer information that provides advances to the field of opinion research by describing the nature of electoral bellwether districts, a topic of recurring interest to public opinion scholars and practitioners. Second, they describe a process for selecting electoral bellwether districts. The authors explore the validity of their ideas by comparing pre-election poll data with bellwether tests to election outcomes for additional races in the state primaries and general election. They offer conclusions about the value and use of bellwether tests in the spirit of an open-source methodology to the opinion research community.