 Their values depend on the suit (or notrump) and whether the contract is doubled or redoubled; they are not affected by vulnerability.Tricks won beyond that necessary to fulfill the contract are referred to as and their scoring points are accounted for separately because their values are dependent upon declarer's vulnerability.When declarer makes overtricks, their score value depends upon the contract denomination, declarer's vulnerability and whether or not the contract is undoubled, doubled or redoubled.