Public Election Polls are 95% Confident but only 60% Accurate

In this paper, we investigate the calibration of public election polls.We present a definition of poll accuracy based on whether the poll’s margin of error spans the true election outcome. Most polls provide a 95% confidence interval along with the poll results, we sought to find whether their accuracy is as high as their confidence lev-els claim. Furthermore, we also wanted to see how this accuracy evolves over time as polls are conducted closer to the actual election.We find that even a week away from the election, polls claiming95% confidence are only accurate 60% of the time. Moreover, we conclude that these polls would in fact need margins of error twice their reported width in order to be truly 95% confident. This pro-vides a unique insight into the adjustment polls need over time and quantifies the systemic error polls contain beyond what the traditional statistics captures.