Electoral System Seat Allocation & Disproportionality Simulator

Political Science Engine: Single-Member District vs. Proportional Representation
Parliamentary Chamber Seat Distribution Total Seats: 465
Gallagher Index
8.42
Disproportionality
Wasted Votes Ratio
34.2%
Votes with zero seats
Majority Threshold
Party A Majority
233 seats needed
National Party Vote Sentiment Adjust Shares (%)
Party A 40%
Party B 35%
Party C 25%
Live Electoral Translation Summary
Party A gained +12.0% seat share over vote share due to district concentration.
Party A: 250 seats (53.8%) | Party B: 165 seats (35.5%) | Party C: 50 seats (10.8%)

Understanding Disproportionality

The Gallagher Index measures the difference between the percentage of votes received and the percentage of seats allocated. Under Single-Member District (FPTP) systems, concentrated voter sentiment often creates a "winner's bonus", whereas PR (D'Hondt) reduces this disparity.

Regional Representative District Model
District Voters Party A % Party B % Party C % SMD Winner
PR Quotient Table Simulation (First 5 Rounds)
Divisor Party A Party B Party C
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