Raise pocket 9's in EP?

[MJL]

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I'm currently reading "Small Stakes Hold'em"(Miller, Sklansky, Malmuth), and the authors seem to struggle with your question too. In their discussion of medium pairs(99, 88, and 77), the authors say,

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From early position you should usually limp in.(p.66)

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They say you either want to play against 2 or 3 players or 5 or more players. Against 2 or 3 players an unimproved pair can win. Against 5 or more players, you are hopping to hit a set and win a big pot. It's approximately 7:1 against hitting a set on the flop, so you have to have enough players to be able to extract more than 7 times your preflop call when you make your set. They recommend only raising with medium pairs when you are in late position and there is exactly one limper ahead of you.

However, in their preflop charts where they recommend the proper action, the author's say to raise with 99 in middle or late postion in a tight game(p. 80) and raise with 99 in early position in a loose game(p. 82).

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This is exactly my understanding. This is why I question all of the posters who have advocated a raise in EP. They give the advice as if it is obvious. I am open to learning so I will not dismiss the idea with out hearing their points.