Heuristics in Multi-Winner Approval Voting

In many real world situations, collective decisions are made using voting. Moreover, scenarios such as committee or board elections require voting rules that return multiple winners. In multi-winner approval voting (AV), an agent may vote for as many candidates as they wish. Winners are chosen by tallying up the votes and choosing the top-$k$ candidates receiving the most votes. An agent may manipulate the vote to achieve a better outcome by voting in a way that does not reflect their true preferences. In complex and uncertain situations, agents may use heuristics to strategize, instead of incurring the additional effort required to compute the manipulation which most favors them. In this paper, we examine voting behavior in multi-winner approval voting scenarios with complete information. We show that people generally manipulate their vote to obtain a better outcome, but often do not identify the optimal manipulation. Instead, voters tend to prioritize the candidates with the highest utilities. Using simulations, we demonstrate the effectiveness of these heuristics in situations where agents only have access to partial information

Polls, Coalition Signals, and Strategic Voting: An Experimental Investigation of Perceptions and Effects

The paper investigates how poll information and coalition signals affect strategic voting, defined as casting a vote for a party other than the most preferred party to better influence the election outcome. In particular if the outcome of an election is perceived to be close, voters in multi-party systems with proportional representation and coalition governments should have an incentive to cast a vote for the party that best influences the formation of the next government. The study focuses in particular on voters’ attention to and perception of polls and coalition signals sent by parties before elections. The study used an innovative design that embedded a laboratory experiment in two real election campaigns, allowing the manipulation of poll results and coalition signals in a realistic environment. The findings suggest that political sophistication plays a crucial role for the accurate perception of polls and strategic voting. Coalition signals are found to have a surprisingly strong effect on (apparently) strategic voting.

Strategic Voting in Multiparty Systems: A Group Experiment

The paper tests the theory of strategic voting for multiparty systems with proportional representation and coalition governments at the micro-level. The study focuses in particular on the question whether participation in repeated elections allows voters to learn from experience and enables them to optimize their decision behavior. An economic group experiment with decision scenarios of varying degrees of difficulty was used to test decision making at both the individual and group level. The results suggest that a majority of voters were able to pursue successful decision strategies and that the difficulty of the decision scenarios affected the voting performance of the participants as expected. However, a learning effect is not supported by the data.

Polling bias and undecided voter allocations: US Presidential elections, 2004 - 2016

Accounting for undecided and uncertain voters is a challenging issue for predicting election results from public opinion polls. Undecided voters typify the uncertainty of swing voters in polls but are often ignored or allocated to each candidate in a simple, deterministic manner. Historically this may have been adequate because the undecided were comparatively small enough to assume that they do not affect the relative proportions of the decided voters. However, in the presence of high numbers of undecided voters, these static rules may in fact bias election predictions from election poll authors and meta-poll analysts. In this paper, we examine the effect of undecided voters in the 2016 US presidential election to the previous three presidential elections. We show there were a relatively high number of undecided voters over the campaign and on election day, and that the allocation of undecided voters in this election was not consistent with two-party proportional (or even) allocations. We find evidence that static allocation regimes are inadequate for election prediction models and that probabilistic allocations may be superior. We also estimate the bias attributable to polling agencies, often referred to as "house effects".Comment: 32 pages, 9 figures, 6 table

What makes voters turn out: the effects of polls and beliefs

We use laboratory experiments to test for one of the foundations of the rational voter paradigm - that voters respond to probabilities of being pivotal. We exploit a setup that entails stark theoretical effects of information concerning the preference distribution (as revealed through polls) on costly participation decisions. We find that voting propensity increases systematically with subjects' predictions of their preferred alternative's advantage. Consequently, pre-election polls do not exhibit the detrimental welfare effects that extant theoretical work predicts. They lead to more participation by the expected majority and generate more landslide elections

Stability in a Sea of Volatility: The Predictive Power of Elite Endorsements in the 2012 Republican Presidential Primary

This analysis builds on previous scholarship by explaining the 2012 Republican Primary through elite endorsements, polls and trends in Internet search volume. Consistent with previous research, elite endorsements were found to be a significant predictor in the 2012 contest. Trends in Internet search volume were found to correlate with poll support for candidates, especially relatively unknown candidates, or candidates outside of their home territories. Contrary to previous scholarship, a subgroup of elite endorsers were found to respond directly to popular support when making their decision

Polls and voting behavior: the impact of polling information on candidate preference, turnout, and strategic voting

textPublic opinion polls have become an integral part of the coverage of presidential elections. The story of the campaign is often told through the lens of the horse-race; candidates are leading or trailing, gaining or losing ground in their efforts to capture the White House. These polls, which provides important information to the public about the views of their fellow citizens, may also serve to shape the opinions and actions of that public, particularly in determining which candidate to support, whether or not to show up on Election Day, and whether to vote sincerely or strategically. Using both an analysis of a well-established national survey over the past ten elections and the results of a set of experiments done at the University of Texas, this study examines the effects of polling information on those decisions, keeping in mind that not all individuals will to react to the same information in the same way. The results of this study indicate that while polls do have an impact on the opinions and behaviors of those exposed to them, the effects themselves are minimal, and tend to largely reinforce existing predispositions. Those who have already chosen a candidate to support in an election tend to use the poll results to reinforce those preferences. Potential voters who are exposed to information suggesting a close election are more likely to participate, but only marginally so. Individuals who are considering whether or not to vote for a third party candidate do react to the strength of that candidate in the polls, but seem unimpressed by the strategic situation. Overall, this study indicates that the strong emphasis by the media on the relative popularity of the candidates does not seem to make a significant difference in the actions of individuals, and thus in the results of presidential elections.Governmen