Instant-runoff voting: Difference between revisions
Added exponential summability note
(→How IRV works: Linking to Truncation) |
(Added exponential summability note) |
||
Line 225:
===Logistical issues===
Ballots in IRV cannot be easily summarized.<ref group="fn">IRV can be summarized in <math>\Theta(n2^n)</math> space by keeping a [[FPTP]] count for every possible selection of eliminated candidates, but this is not useful in practice.</ref> (Political scientists call this the [[Summability criterion]].) In most forms of voting, each district can examine the ballots locally and publish the total votes for each candidate. Anyone can add up the published totals to determine the winner, and if there are allegations of irregularities in one district only that district needs to be recounted.
With IRV, each time a candidate is dropped, the ballots assigned to them must be re-examined to determine which remaining candidate to assign them to. Repeated several times, this can be time-consuming. If there is a candidate X who got more votes than all of the candidates who got less than X put together, then all of these candidates who lost to X can be dropped simultaneously without affecting the final outcome, which can speed up counting.
Line 613:
*[[Table of voting systems by nation]]
*[[Bottom-Two-Runoff IRV]] - a variant that meets the Condorcet criterion
== Footnotes ==
<references group="fn"/>
== References ==
| |||