FORCING PASSES
SSS by Danny Kleinman

SAYC. A pass is forcing (partner must bid or double) when the opponents are clearly competitively bidding for preemptive reasons and you are unsure whether to double or bid more.

SSS. A pass is forcing (partner must bid or double) when you or your partner's previous calls have forced the auction beyond your opponent's bid, or when the opponents are clearly sacrificing against your game contract or higher. But you pass cannot be forcing merely because an opponent is clearly preempting or competing, for if your side hasn't previously shown great strength, you may pass simply because you aren't confident of beating the opposing contract.