Phil Rockmore: Why Equity-Based Models Fail in Poker Preflop Decisions

Poker strategy expert Phil Rockmore delves into the intricacies of preflop range construction and its impact on postflop expectations. Rockmore argues that using equity-based models for preflop decisions is fundamentally flawed. He explains that players often mistakenly believe that preflop equity corresponds to postflop expectations, leading to suboptimal play.

Rockmore highlights two main errors in using equity-based models. First, players assume that preflop equity of a hand against a range roughly matches the expectation of playing that hand. For example, calling a 3.5 big blind raise with a hand that has 33% equity seems reasonable based on pot odds. Second, players believe that a hand's equity on the flop against a range corresponds to the expectation of playing that hand. Rockmore uses an example where a player on the big blind with Jc 9s 4c 2d sees a flop of Qd Jh 8s, has 30% equity, and a 7.5 big blind pot, leading to an expected value of 2.25 big blinds.

Rockmore provides a practical example where a tight player on early position raises, and the big blind has Qc 8h 7s 2h. He uses the Odds Oracle program to build a model of equity distribution for this hand against the opponent's range. Rockmore discusses the concept of minimum equity and how often a hand will have a certain equity against an opponent's range. He explains that the equity of a hand should be considered in the context of the opposing ranges. Rockmore provides examples of different flop textures and how they affect the equity of a hand and the overall range. He notes that on flops highly favorable to the opponent, the equity-based model fails, leading to significant losses.