I've just skimmed through TJ's book again recently (I really need to buy some other poker material...Theory of Poker will most likely be my next read). TJ very strongly advises that you should "A better or a raiser be, a caller never be" unless you are setting a trap or chasing a draw with pot odds. On the surface, this makes perfect sense of course. You raise, and you have two chances to win (they fold, or you have them beat). If you just call you need to have the best hand. You also hear people say "I raised him to find out where I was at. When he came back over the top of me, I knew I was beaten." You learn something with a raise.

However,

I'm going to pull a Mike Caro and question conventional poker wisdom for a second. For raising your opponents bet post-flop to make sense, I think you need to have folding equity. There needs to be a chance that you will make your opponent fold a better hand than you have. If the range of hands that are better than yours are most likely too strong for your opponent to lay down, or your opponent is too weak to realize that he "should" lay these hands down, then there is no folding equity.

But what about the information gained with a raise? What about losing a little with a 2nd best hand vs. losing a ton with a 2nd best hand that goes to a showdown?

Yes, there is this. However, keep in mind that you also give out information with a raise as well as receive it. You may scare away a 2nd best hand that might have put you on a draw or 2nd best if you had just called and therefore kept betting and added value to your hand.

In conclusion:

Instead of almost always raising/folding with hands that may or may not be the best hand, perhaps it is sometimes greater +EV to just call. This depends on folding equity of a raise vs. value lost with a fold, taking into consideration the range of hands your opponent will bet with and how much or how little of a "calling station" they are.

Thoughts?