by Norm Wattenberger

Chapter 5. Error Data

Nearly all the Blackjack statistics we read about ignore errors. The books warn us about errors, but rarely quantify the effects. In this chapter we will take a quick look at errors both pro and con.

"With every mistake we must surely be learning." — George Harrison, 1968

How do dealer errors affect us?

The large number of new casinos suggests that dealer errors will occur with greater frequency than in the past. Errors can help or harm the player. First we will look at dealer errors that help the player. You don't have to do anything to gain from these errors. Although there are some players that try to increase dealer errors.

The green bars indicate the SCORE for a typical Strip six-deck game. The red bars indicate the gain from four types of errors as follows:

  • Pay Pushes – The dealer will sometimes pay tied hands instead of pushing the bet. The first red bar shows the gain if this happens in 1% of tied hands.
  • Push Losing Hands – The dealer will also sometimes push a losing hand. The second red area shows the gain if the dealer does not take the bet in 0.2% of losing hands.
  • Pay Early Bets – If a player busts, he/she sometimes will put up a bet before the dealer plays his/her hand. If the dealer then busts, he/she will sometimes pay the early bet. The red area in the third bar indicates the gain if this happens 10% of the time that both the player and dealer bust. The frequency of this situation depends on the number of players. It cannot occur with one player at the table since the dealer cannot bust if all players (in this case, just the one) bust.
  • Bust on Long Hand 21 – A 21 made up of four or more cards is treated as a bust 10% of the time.

This chart indicates that tricking the dealer into paying early bets is generally not worth it.

What about errors that favor the dealer?

Dealers also make errors that harm the player. It is important to watch out for these errors. Do not trust the dealer to count up the cards correctly — this could cost you. In this chart, the red area is the SCORE if you miss the error. The blue area is the loss from the error if you do not catch it and point it out to the dealer. Three error types are displayed:

  • Lose Pushes – Pushed hands will randomly lose at a 1% rate.
  • Push Winning Hands – Winning hands will lose 0.2% of the time.
  • No bust on Dealer 22 – A four or more card dealer 22 will be treated as a 21, 25% of the time.
It's important to remember that dealer errors can harm you only if you don't catch them.

Sim details

  • Six decks, S17, DAS, LS, 4 players, 4.81/6 penetration, Hi-Lo, truncate, full indexes, half-deck resolution, spread 1-15
  • Seven different errors.
  • Two billion rounds each, all sims use optimal betting, full Kelly


copyright © 2007, 2024, Norm Wattenberger, All rights reserved