A very important skill in bidding is to select the best call, when more than one call is reasonable. In our research, we found large differences in how stronger players made these decisions, versus how less experienced players made the same decisions. The less experienced players tended to use relatively rigid decision rules, but the stronger players tended to consider all possible calls, selecting the one that was the best fit with the player’s actual cards.
An important example is the decision whether to enter the auction when your right-hand opponent (RHO) opens the bidding. Many less experienced players appear to follow this sort of decision rule: “Don’t pre-empt, it’s too risky; don’t overcall in notrump, it’s too risky; with an opening bid and a five-card suit, overcall in the long suit; with any other opening bid, make a takeout double; without an opening bid, pass”. By contrast, stronger players take a wide variety of factors into account and consider a much wider range of possible calls.
For more information on these essential competitive bidding decisions, see Real World Bridge 4: Competitive Bidding Part One.