Sucker said:
According to my blackjack simulator, if you double down you'll earn 89 cents for a $10 bet; and if you just hit, you'll earn 86.7 cents. You gain 2.3 cents by doubling.
Here is my question to all blackjack players who are risk-averse when it comes to doubling: Why would you bet $10 off the top of the deck when the advantage is in the houses' favor, yet be afraid to put another 10 bucks out for a double down, when YOU have the advantage?
As far as the argument that it's a borderline play anyway (with all due respect for Blue Efficicay); Card counting ITSELF is a borderline venture. When you play blackjack for profit you'll be constantly making borderline decisions, and if you fail to take FULL advantage at all times, then you will risk setting yourself up for failure long-term.
Betting $10 OTT is different from making a borderline double. Betting money OTT is a play we make for the sake of cover (Playing only +counts while staying at the table is very suspicious). Unless we are wonging, shuffle tracking, or some other advanced technique, there is not much we can do about making that OTT bet. We make the bet assuming that we will experience more longevity, allowing us to extract more $ at that casino.
Considering to double with another $10 for a high variance, low expectation double is a thought process that considers the variance that our bankroll will experience for a small gain. This is a decision that has no outward advantage. We are asking whether the risk of losing $10 is worth the extra 2.3 cents. RA indeces can answer that question (which btw uses CE to calculate said index).
Borderline plays are plays that, by definition, have little to no cost to the player. While not taking full advantage will reduce your growth potential, it is definately not enough such that you are going to be losing in the long run. ZGs interview describes his use of rounded indeces and cover techniques like literal coin flips to dictate his action when in a borderline zone for a index play.