A busy person’s introduction to ranked-choice voting
This post describes the basic forms of ranked-choice voting (RCV). I wrote it because I often find myself directing journalists and others to this paper published in 2021 at the journal, Politics and Governance, and it is too long and complex for most purposes. If you’re in a hurry, this post may help to understand the differences below before making judgments about RCV writ large.
I find it helpful to analyze RCV along two dimensions. One concerns how votes turn into winners. The other is how it alters (or not) the rules for choosing nominees.
First, RCV can be used to try to get any of three outcomes: one majority winner in a single-seat district, majority and minority seats in a multi-seat district, or one majority slate with all seats in a multi-seat district.
The table below lays out some RCV forms based on classic categories in political science. Those categories are: district magnitude (number of seats), ballot type (all ranked in this case), and allocation rule (how the votes are processed). The table is from this set of slides.
Two forms do not map well onto the ‘three big goals’ I described above. These are bottom-up and AV (Alternative Vote) with numbered posts (not included above). I do not know where bottom-up originated. It carries less risk than the block-preferential system of cutting off numerical-minority representation. (A coauthor once suggested it behaves like the single non-transferable vote, but that is a topic for another day.) AV with numbered posts basically aims for a single-slate delegation. It is more or less a residue of the commission form of local government, which involved citywide elections to a series of functional offices (parks commissioner, water commissioner, etc).
The second thing to keep track of is how RCV might change nomination rules.
For example, Alaska, Maine, and New York City all use what’s called AV above. But Alaska uses it to obviate nominations, whereas the other two places use it in nominating primaries. Maine also uses it in congressional general elections.
One way to think about this aspect is: choice among parties (Maine congressional generals), choice within parties (Maine or NYC primaries), and choice without regard to parties (Alaska).