RCV-IRV — concept pages

Everything explaining RCV-IRV — ranked ballots counted by instant runoff (IRV): rank the candidates, eliminate the last-place candidate each round, transfer their ballots, repeat until someone has a majority of continuing ballots.

First, the word. "RCV" names a ballot (ranked); "IRV" names one tabulation of it. Start here so the rest reads precisely:

• Is it RCV or IRV? (and why "RCV-IRV") — the house-terminology page
• RCV vs. IRV vs. RCV-IRV — a note on terminology
• RCV-IRV (Hare) — the specific method US "RCV" almost always means

The case for it

• Why RCV-IRV — the case for it, made fairly — what the method genuinely gets right, made the way its advocates make it: it fixes the ordinary spoiler, guarantees later-no-harm and mutual majority (both of which STAR fails), is clone-independent, and is the reform that actually passed. Read this before the critiques below, or you'll be arguing with a strawman.

How it counts

• Is RCV "simple"? — which half? — the ballot is simple; the count is not
• Is RCV-IRV "just plurality in sequence"?
• Exhausted (inactive) ballots — ballots that drop out of the count mid-tally
• Elimination ties — who gets cut when two are tied for last — the tie IRV has that STAR doesn't, and the one that matters most: whichever candidate you cut transfers different ballots, so it reshapes every round after it. Also batch elimination (what happens when everyone is tied) · the Ties & Tie-Breaking hub · what our engine actually does

The IRV-specific critiques

These are properties of IRV the tabulation, not of ranked ballots in general (Ranked Robin isn't squeezed) — keep them attached to IRV:

• Center squeeze — the moderate eliminated early
• Non-monotonicity — when more support makes you lose
• Not summable — every ballot must be counted centrally, and that central count has costs
• Fails the Equal Vote criterion
• Exhausted ballots (301) · forced vs. voluntary exhaustion
• Misconceptions & false claims — an index

Variants — other tabulations of the ranked ballot

The variants/ subfolder — same ranked ballot, different elimination rule:

• Which RCV-IRV? — the variants & tie-breaks · family tree
• BTR · Baldwin & Nanson (Borda-elimination, Condorcet-safe) · Coombs (eliminates on last choices) · Contingent & Supplementary

Case studies — RCV-IRV in the wild

The case_studies/ subfolder — real elections:

• Alaska 2022 — spoiler + center squeeze + non-monotonicity in one federal race
• The Alternative Vote in Australia — a century, assessed evenhandedly
• North Carolina · History

Reference

• Glossary: RCV-IRV & ranked-ballot terms

(Other tabulations of the same ranked ballot: Ranked Robin (Condorcet/consensus), STV (proportional). Up: the docs hub 00_START_HERE.)