narrow-loss ratio; margin-of-loss ratio
Technical term in Japanese electoral politics: the ratio of a losing candidate's vote count to the winner's vote count in a single-seat district, used to rank candidates for proportional representation seats when ties occur.
Proportional representation revival seats are decided in descending order of the narrow-loss ratio.
He lost in the single-seat district, but because his narrow-loss ratio was high, he won a proportional seat.
Compound of 惜敗 (sekihai, 'narrow loss') and 率 (ritsu, 'rate, ratio'). The term is specific to Japanese electoral law and has no direct pre-modern equivalent.