Estimating polling accuracy in multi-party elections using surveybias

Any rigorous discussion of bias in opinion surveys requires a scalar measure of survey accuracy. Martin, Traugott, and Kennedy (2005, Public Opinion Quarterly 69: 342–369) propose such a measure A for the two-party case, and Arzheimer and Evans (2014, Political Analysis 22: 31–44) demonstrate how measures A′i, B, and Bw for the more common multiparty case can be derived. We describe the commands surveybias, surveybiasi, and surveybiasseries, which enable the fast computation of these binomial and multinomial measures of bias in opinion surveys. While the examples are based on pre-election surveys, the methodology applies to any multinomial variable whose true distribution in the population is known (for example, through census data).