Free showdown

[WhiteWolf]

Jennifer Harmon discusses this play in her Limit Hold'em section of Super System II. The idea here is that your raise on the turn might also have some fold equity, which can increase your EV over just calling the turn + river bets. And if you do chase out a weaker hand, you make money on the times he would have outdrawn you if you took the more passive line. Couteracting this is the risk that you can get re-raised on the turn, forcing you to either fold (losing the chance to outdraw your opponent), or proceed with a now very expensive calldown.