THE PENALTY DOUBLE HAS DIED AND GONE TO HEAVEN
Those were the words of my good friend, Bernie Chazen.
Sadly, he is now in heaven with those penalty doubles, but his words still ring true here on planet Earth.
In 2008, Bernie and I gave a full 2-day seminar on doubles. To start things off, Bernie waddled up to the stage (only those who knew Bernie can picture him with his 300+ pounds, suspenders, confident attitude...) and uttered those words. Then, we spent hours and hours showing how rare it is for a double to actually mean: "I want to increase the penalty."
Without going into extreme detail, here is a wonderful guideline:
A double on the first round of bidding is never for penalty.
Here are some examples:
North's Double is NOT penalty. Is it really likely he will have been dealt hearts?
North's Double is NOT penalty. Why should this be different from #1?
East' Double is NOT penalty. Is it likely he has spades? Negative Doubles should be played on ALL levels (not through 3 or anything like that. In fact, the more they bid, the less likely you are to have their suit.)
South's Double is NOT penalty. One suit he does not have is spades.
South's Double is NOT penalty. Cater to takeout, not to penalty.
South's Double is NOT penalty. Same as #5.
All of these doubles are takeout/cards. They say: "Partner, I have a good hand. I am interested in hearing from you." If the double is on the 4-level (as in 1,2,3,4,6), it will frequently be left in. Not because the partner of the doubler has a trump stack (unlikely), but because he has nothing to take out to. If a 4-level bid is doubled for "takeout" you take it out with shape -- a long suit (usually 5+ cards). If the partner of the doubler is 4-3-3-3, he will typically leave it in and hope to beat them. But, don't lose the main point: THE DOUBLE IS NOT INTENDED FOR PENALTIES.
There are so many more auctions to discuss, but that's it for now. Make sure you and your partner agree that Penalty Doubles are Dead.
More guidelines here.