It's simply ranked choice voting (aka IRV) for the house. "Two-party preferred" is a system used by polls and news to try to convey how they think the runoff vo

It's simply ranked choice voting (aka IRV) for the house. "Two-party preferred" is a system used by polls and news to try to convey how they think the runoff voting will play out, by picking the two candidates most likely to come first and second and showing their expected final tally.