Single transferable votes with tax-cuts

Abstract

Some tally methods for preferential elections are discussed from the following point of view: how well do they respect a wish from the voter that subsidiary votes in the ballot cannot hurt the chances of the ballot’s top-ranked candidate? The tally method of Single Transferable Votes, STV, is constructed to obey this principle without exception, but other defects show up, in particular non-monotonicity, premature eliminations, and free rides. Various modifications of the STV are suggested to reduce the election method’s weaknesses without losing too much of its strengths.