In the early days of bridge main stream players used Doubles mostly (if not always) as Penalty doubles. This would simply increase the penalty for defeat, but also substantially increase the reward for making the contract. Over time this approach has been largely abandoned for two reasons : 1 Doubling of a Part score contract is rarely worth the effort and also highly risky. For example doubling a contract of 2♥ increases the reward if the contract is made from a mere 110 pts to 470 pts !!! The 2♥ contract trick value of 60 is doubled to 120, also receives the Game bonus of 300 points (or 500 when vulnerable) plus another 50 pts "for the insult". Cashing in more than a Game contract for making only 8 tricks ! If the contract does fail the doubling side will be lucky to pick up an extra 1 or 2 Match points against the risk of receiving a bottom score (and of course no Match points at all !). A poor contract will produce a good score for the Opponents anyway ! At the 6 and 7 level Slam contracts doubles are generally used as lead directing doubles (make an "unusual lead" Partner). A penalty double in these cases is a wasted effort, because when the contract fails the opponents will get a good match point score anyway. Penalty doubles (made by experienced players) are therefore mainly restricted to Game contracts which are sacrifice bids (4S, 5C, 5D, 5H), which block the opponents from making a genuine Game contract. 2 When any player makes a bid it provides either opponent with an extra bid, a double, with which to convey valuable positive information to Partner. Without the double this would not be possible. This opportunity occurs frequently, in contrast to the rare occasion of making a penalty double. Penalty doubles below Game level therefore deny the use of a valuable bidding tool. Information doubles can be creatively used in a variety of situations. However after the Opening bid has been made a double as a first bid by any player around the table is a unique convention bid, in each case with a different meaning which you should be familiar with. More details about these position specific doubles here. © 2017 Michael Furstner