Nested row-column and generalized Howell designs used in bridge competitions

In pairs bridge competitions, the same cards are played at a number of tables. At each table, two pairs meet in a match. The pairs then circulate according to some playing scheme, a design, to play other cards against other opponents. In a match, one pair plays what is called the North-South (NS) cards and the other the East-West (EW) cards. If one considers tables as rows and NS and EW as two columns, we realize that nested row-column designs can be used. In this paper a statistical model is formulated and good nested row-column designs with good row component designs are sought. Another block component design with rounds as blocks is often introduced, which means that we require a kind of double resolvability. A generalization of Howell designs can then be useful.