This page contains notes motivated by the playing of two (overlapping) groups in Long Island, NY.

Most of the material deals with duplicate bridge matchpoint scoring as specified by ACBL rules. See ACBL site article on matchpoints. The key part is

At the end of the whole session, each pair is awarded 1 matchpoint for each pair who scored worse than them on a board, and 1/2 matchpoint for each pair who scored equally.

This is equivalent to the scoring in a round robin tournament with 1 point for a win and 1/2 point for a tie.

The Vagaries of Scoring