IPOL - week 9 pdf
Core Concepts and Theories
Strategic Voting: When a voter chooses a candidate/party that is not their most preferred, but is more likely to win or contribute to a desired government outcome (e.g., coalition). The goal is a preferred outcome, not pure preference.
Sincere Voting: Voting for the most genuinely preferred candidate/party, without considering electoral consequences.
Tactical Voting: A specific form of strategic voting where a voter votes against their most preferred candidate for strategic reasons (e.g., to prevent a worse outcome, enable a better one).
First-Past-The-Post (FPTP) Systems: Electoral systems where the candidate with the most votes in a single-member district wins (winner-take-all). Tend to produce two-party systems.
Proportional Representation (PR) Systems: Electoral systems designed to allocate seats proportionally to votes received, often involving multi-member districts or party lists. Allows smaller parties to gain representation.
Instrumental Voting Assumption: Voters make decisions to achieve a desired outcome, not just express a preference.
Key Theorems and Laws
Gibbard-Satterthwaite Theorem: States that only dictatorial electoral systems (where one voter's preference determines the outcome) can be "strategy-proof."
Strategy-proof: Immune to deviations from sincere voting, meaning voters always achieve their best outcome by voting for their true preference.
Arrow's Theorem Conditions: Imply the impossibility of a perfect social choice mechanism that satisfies basic fairness criteria without being dictatorial.
Conclusion: This means strategic voting is inherently allowed in virtually all real-world democratic systems (FPTP and PR), as they are non-dictatorial.
Duverger's Law (1963):
Posits that FPTP, single-member district systems tend to lead to two-party systems.
Mechanical Factor: FPTP disproportionately allocates seats to large parties; only the top vote-getter wins, 'wasting' votes for losers.
Psychological Factor: Voters strategically defect from preferred, but weak, candidates to avoid 'wasted votes.' They choose a viable candidate, often one of the two major parties, to prevent their least preferred major party from winning.
Expected Strategic Deviations: Typically expected to be higher in FPTP due to the winner-take-all nature.
Comparison with PR Systems on Strategic Voting:
Reduced Mechanical Factor: PR systems minimize 'wasted votes' by allocating seats more proportionally, even to smaller parties.
Psychological Factor: Traditionally assumed minimal in PR, but strategic voting does occur, shifting from electing a candidate to influencing which coalition forms the government.
District Magnitude () Impact: Higher district magnitude () can dilute individual strategic votes but increase strategic voting related to parties within potential coalition blocs.
Study's Core Hypothesis and Findings
Hypothesis: Levels of strategic voting are similar across FPTP and PR systems.
Findings:
Substantial voter desertion (not voting for most preferred candidate) observed in both FPTP and PR systems.
Key Observation: Smaller parties consistently lose votes to larger parties.
Distinction: PR systems actually show higher rates of tactical voting. This is because they have more small parties, which amplifies coalition considerations for voters.
Voters are rational and instrumental, prioritizing policy consequences and likely influence on government formation.
Methodology
Comparative Analysis: Survey data from FPTP (US, Mexico, UK) and PR (Israel, Netherlands) systems.
Data Source: Pre-election surveys to capture preferences, expectations, and actual voting intentions to identify strategic shifts.
Conclusion
Affirmation: Strategic voting patterns are remarkably similar across FPTP and PR, challenging the traditional view that PR mitigates strategic behavior.
Drivers: In FPTP, it's about avoiding 'wasted votes' and winning a district. In PR, it's about influencing coalition governments.