Frustration with calculating outs--the "multiple of 4" rule

[Tical]

So I've been under the impression that after the flop, one can multiply their outs by 4 (subtracting a small amount as the outs get more numerous) and after the turn multiply outs by 2 (adding on a little as the outs grow). This seems like a fairly efficient way to approach the issue, especially at a soft home game.

So why don't any of the poker books acknowledge this idea??? Even HOH (which I'm enjoying because Harrington takes are fairly relaxed and realistic approach to odds/outs)does not discuss this seemingly great way to weigh outs against the pot odds.

Can anybody offer some insight?? Thanks a ton.

[LetYouDown]

Because it's really only a decent approximation. When you get to large numbers of outs, the difference becomes pretty significant. For players that don't really think about the reasoning behind it, it can lead to some poor decisions.