10.1 Voting Systems and Collective Decision Making

Voting systems shape how we make collective decisions in democracies. From first-past-the-post to ranked-choice, each method has unique impacts on representation, party strategies, and political stability.

This topic dives into the pros and cons of different voting rules and methods. We'll explore how these systems affect fairness, efficiency, and strategic voting behavior in elections and decision-making processes.

Voting Systems and Collective Decisions

Types of Voting Systems

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• First-past-the-post (FPTP) voting system awards victory to candidate with most votes, even without majority (used in UK, US)
• Proportional representation allocates seats based on vote proportion, promoting diverse representation (used in many European countries)
• Ranked-choice voting (RCV) allows voters to rank candidates, potentially leading to consensus-based outcomes (used in Australia, Ireland)
• Two-round system requires majority, with runoff between top candidates if no majority achieved in first round (used in France)
• Mixed electoral systems combine different voting methods (Germany's mixed-member proportional representation)
• Each system impacts voter behavior, party strategies, and elected body composition differently
• Voting system choice influences political stability, minority view representation, and coalition government formation

Implications of Voting Systems

• FPTP often results in two-party dominance, potentially excluding minority views
• Proportional representation can lead to more diverse parliaments but may result in coalition governments
• RCV may reduce strategic voting and encourage more positive campaigning
• Two-round systems can promote consensus-building but may lead to voter fatigue
• Mixed systems attempt to balance local representation with proportionality
• Voting systems influence campaign strategies (focusing on swing states in FPTP vs broad appeal in proportional systems)
• Electoral thresholds in proportional systems can affect small party representation (5% threshold in Germany)

Voting Rules: Advantages vs Disadvantages

Majority and Unanimity Rules

• Majority rule bases decisions on >50% support, promoting efficiency but risking tyranny of the majority
• Unanimity requires agreement from all participants, ensuring all views considered but potentially causing gridlock
• Qualified majority voting requires supermajority (two-thirds in UN Security Council)
• Condorcet method elects candidate winning majority of head-to-head comparisons (rarely used in practice due to complexity)
• Borda count assigns points based on rankings, potentially leading to moderate outcomes but vulnerable to strategic voting
• Approval voting allows voters to approve multiple candidates, potentially reducing negative campaigning
• Each rule trades off decisiveness, minority interest protection, and manipulation susceptibility

Alternative Voting Methods

• Cumulative voting gives voters multiple votes to distribute, enhancing minority representation
• Single transferable vote (STV) combines ranked voting with multi-member districts (used in Ireland)
• Mixed member proportional (MMP) system combines FPTP with party-list proportional representation (used in Germany, New Zealand)
• Proxy voting allows voters to delegate their vote to a representative (used in some shareholder meetings)
• Liquid democracy combines direct and representative democracy, allowing vote delegation (proposed for online voting systems)
• Each method aims to address specific democratic deficits or representation issues
• Implementation complexity and voter understanding vary significantly among these methods

Efficiency and Fairness of Decision-Making

Theoretical Foundations

• Pareto efficiency occurs when no alternative can improve one's situation without worsening another's
• Arrow's Impossibility Theorem demonstrates no voting system can satisfy all fairness and logical consistency criteria simultaneously
• Social welfare functions attempt to aggregate individual preferences into societal ranking of alternatives
• Fairness assessed through criteria anonymity (voters treated equally), neutrality (candidates treated equally), monotonicity (increased support shouldn't harm a candidate)
• Efficiency measured by ability to produce timely, stable outcomes
• Transaction costs (information gathering, negotiation) affect overall decision-making efficiency
• Trade-off between inclusiveness and efficiency key in institutional design

Practical Considerations

• Deliberative democracy emphasizes informed discussion before decision-making (citizens' assemblies)
• Consensus decision-making aims for group agreement rather than majority rule (used in some cooperatives)
• Delphi method uses iterative anonymous feedback to reach expert consensus (used in forecasting)
• Cost-benefit analysis attempts to quantify decision outcomes for comparison (used in public policy)
• Participatory budgeting allows citizens direct input on budget allocation (implemented in Porto Alegre, Brazil)
• E-democracy tools can increase participation but raise concerns about digital divide and security
• Balancing expert knowledge with democratic input remains a challenge in complex decision-making

Strategic Voting and Election Outcomes

Strategic Voting Behavior

• Strategic voting involves casting ballots not based on true preferences but to influence election outcome
• Gibbard-Satterthwaite theorem proves all non-dictatorial systems with ≥3 candidates are susceptible to strategic voting
• Duverger's law suggests plurality voting favors two-party system due to strategic behavior
• Tactical voting in multi-party systems can lead to "spoiler effect" (similar candidates split vote, allowing less preferred candidate to win)
• Game theory models (prisoner's dilemma) analyze strategic voting behavior and equilibrium outcomes
• Polls and exit polls impact strategic voting, potentially creating self-fulfilling prophecies
• Multiple round or transferable vote systems may reduce strategic voting effectiveness by allowing preference expression

Impacts on Electoral Systems

• Strategic voting can lead to vote swapping in different constituencies (UK general elections)
• "Favorite betrayal" occurs when voters abandon preferred candidate to prevent least preferred from winning
• In proportional systems, strategic voting may involve supporting coalition partners to ensure government formation
• Tactical voting websites provide recommendations based on polling data (controversially used in UK elections)
• Some countries prohibit publication of polls close to election day to reduce strategic voting (France, Italy)
• Ranked voting systems aim to reduce need for strategic voting by allowing full preference expression
• Electoral system design must consider trade-offs between reducing strategic voting and other democratic values (simplicity, accountability)