Blackjack Player Errors

How do player errors affect us?

This is an attempt to show examples of the cost of player errors when counting cards. Note that these costs are highly dependent on many variables. Three sets of columns are provided using data from six-deck, Strip games. The height of the columns represents SCORE.

The first set of columns displays the effects of betting errors for a non-cover card counter spreading 1 to 12. The errors are betting incorrectly by one count. For example, betting the amount for true count +2 when the count is only +1. The red column gives the SCORE with no errors. Succeeding columns toward the front increase the error rate by 1%, or one error per hour playing 100 rounds per hour. The effect of errors is not enormous because we are still getting the money out when needed. Just not the optimal bet.

Column set 2 displays the effect of playing errors in the same manner. The errors are serious, but not idiotic. Insure is reversed, surrender is reversed, split or double is changed to hit, hit and stand are reversed. But, a hard 18 up is never hit, an eleven is never not hit, and a double or split is never taken when it shouldn't be. Playing errors of this type in this set of circumstances are far more severe than betting errors.

Column set 3 displays the effect of misestimating the remaining cards for true count calculation. The green bar shows the effect of a 10% error and the blue shows the effect of an additional 10% error.

How about single-deck?

The same error scenarios in single-deck have a somewhat stronger impact. This is not surprising as single-deck is more sensitive to everything. Estimation errors are not provided here as this is extremely sensitive to the exact method of true count calculation and would be misleading in a general case.

Again, all of the scenarios on this page are highly dependent on exact circumstances and this is meant only as a very general example.


Sim details

  • Six decks, S17, DAS, LS, 4 players, 4.81/6 penetration, Hi-Lo, truncate, Ill18 & Fab 4 indexes, half-deck resolution, spread 1-15
  • Single-deck, H17, 2 players, 4 rounds, Hi-Lo, truncate, full indexes, quarter-deck resolution, spread 1-4
  • Various errors.
  • Two billion rounds each


copyright © 2007, Norm Wattenberger, All rights reserved