In the course of putting opponents on a range of hands by factoring in styles and betting patterns, you attempt to conclude whether you have the best hand.
The top pros also try to determine whether they are a big enough favorite to make it worth risking all their chips.
In today's hand from the 2009 World Series of Poker $10,000-buy-in main event at the Rio in Las Vegas, with blinds at $250-$500 plus a $50 ante, the woman in the hijack seat raised to $1,500 and got called by the player immediately to her left.
Greg Raymer, the 2005 WSOP main event champ, found A-Q offsuit in the small blind. Raymer called, as did the big blind, actor Jason Alexander.
Four players took a flop of Q-5-Q with two hearts, giving Raymer trips. Alexander bet $2,500. The other two players folded.
"I didn't think there was any chance Jason would bet there with a flush draw," Raymer said. "I thought he would check and fold. So I put him on a queen or pocket 5s, or maybe a pocket pair like jacks or 10s where he wanted to see a flop."
Raymer called. The turn came the 10 of clubs. Raymer checked. Alexander bet $6,000. Raymer called.
The river came the 4 of diamonds. Raymer checked again. Alexander made it $12,000. Raymer called. Alexander showed Q-3 offsuit, getting outkicked by Raymer's ace.
So Raymer took the pot -- with regret.
"I underplayed the hand," Raymer said. "I should've played the hand faster. If I check-raise the turn or the river, I might've gotten all the chips in. I should've been willing to take that risk.
"I should've given him a broader range. If I had, I would've been a bigger favorite over that whole range and now I'm willing to risk all my chips in that spot."
Trips: Three of a kind where one hole card matches two on the board.