The offence to defence ratio (ODR) refers to how a hand will perform differently when it is played as a declarer or a defender. A high ODR means that the hand is better played as a declarer, while a low ODR means that the hand is better played as a defender. It is not a formalised concept and has no clear mathematical formula for it. For example, the following hand has a very high ODR: It can be played greatly in ♥s, guarantees 7 tricks even opposite a partner with no values, but can take at most 2 tricks if the contract is in a suit other than ♥s. * long and solid trumps * side shortness