Introduction
Public opinion polls, widely used and relatively low in analytical complexity, are often highly accurate for election forecasting (Boon, 2012; Graefe, 2014; Hillygus, 2011). However, in highly contested elections where variability in voter intention is high, a prudent polling organization may want assurance that a single poll result is not biased. Bellwether counties or cities that are known to mirror statewide preferences can help provide this assurance, quickly and inexpensively. In other words, bellwether polls are combined with polls of larger areas as sister-teststoward development of more accurate pre-election predictions. While statewide polls yield vote share percentage...