Double jeopardy benchmarks for political polls

Abstract

Consumer goods marketers often benchmark brand performance against known patterns of consumer loyalty, such as the law of double jeopardy. This law states that lesser known brands suffer twice; fewer people buy them, and those that do like them less and are less loyal. Unless double jeopardy effects are understood the performance of a small brand may be misinterpreted as poor when it is in fact normal for a brand of that size. Political opinion polls also show double jeopardy effects, although the evidence base remains thin. We provide fresh evidence of double jeopardy in political opinion polls in a New Zealand context, and show how to benchmark politicians' performance against the double jeopardy line. We discuss insights arising from this new method of analyzing political performance.