The second potential mechanism through which polls may affect the vote is a contagion effect. If there is a contagion effect, voters should come to evaluate the parties and the leaders who are doing well in the polls more positively and those who are not doing well more negatively. If all of the polls’ effect is accounted for by contagion, we should find that polls had an impact on ratings of parties and of leaders and that it is only because of these evaluations that they affected the vote, that is, the polls had no independent effect on the vote once preferences were taken into account. A news article on the subject of political economy in the Insight by Stanford Business written by Snyder, B. (2012), he says “polling data helps voters get
