Indices differentials

[qwerty]

I have used a couple of different programs to create indices based on the type of game I will be playing and seem to be coming up with different numbers which also come up different than some of the Illustrious 18. How should I decide which indices are correct? Was Ill. 18 based on a 6D game? Most of the games I am playing are DD. Which would be a better source, Bj-strat or the strategy file for DD included with Powersim?

[sagefr0g]

Originally Posted by qwerty

I have used a couple of different programs to create indices based on the type of game I will be playing and seem to be coming up with different numbers which also come up different than some of the Illustrious 18. How should I decide which indices are correct? Was Ill. 18 based on a 6D game? Most of the games I am playing are DD. Which would be a better source, Bj-strat or the strategy file for DD included with Powersim?

as i recall the i18 was based on a four deck game 1-12 spread. i think it was also s17.
don't know about bj-strat or powersim.

[callipygian]

The Illustrious 18 will change dramatically with your style of play, and as a matter of fact, I've been unable to find on the Web one single authoritative list of what the I18 actually is.

This makes sense - if you're Wonging out of negative count shoes, then you really don't care when hard 12 v. dealer 4 becomes hit, since you're always gone by that point. If you're spreading 1-10 slowly, the changes at low positive TC matter less than the changes at high positive TC.

I got sick of it and made my own list, so I can't really help, other than to make a list of all the "common" indices that tend to show up on every list I've seen.

[Sonny]

I haven’t seen the numbers from Powersim but I have used the BJ-Strat program and I have found it to be accurate. The numbers will vary somewhat depending on what method you use to calculate them but they should be within 1 or 2 points of each other (unless they are risk averse or something drastic like that). In the long run it doesn’t really matter which numbers you use. If a particular decision is off by 1 or 2 points (or even 5!) the results will not change much. Calculating indices is a fairly vague art so you should take those numbers with a grain of salt anyway. Here's a link to an old discussion:

http://www.blackjackinfo.com/bb/showthread.php?t=7794

-Sonny-

[callipygian]

Originally Posted by Sonny

Calculating indices is a fairly vague art so you should take those numbers with a grain of salt anyway.

Only because of the assumptions that people make before the calculations begin. The value of an index is simply Sum(i = I to 20) {P[sub]i[/sub]*P[sub]scenario[/sub]*Bet[sub]i[/sub]*(EV[sub]change[/sub]-EV[sub]BS[/sub]} where i is the TC, I is the index, and P[sub]scenario[/sub] is the probability of the scenario at count i. Everyone has a different Bet[sub]i[/sub]'s, and Wongers have different P[sub]i[/sub]'s, so the values all come out different.

The reason why insurance is almost always at the top is because P[sub]scenario[/sub] is large. For all other scenarios (e.g. hard 7 vs. dealer 6), P[sub]scenario[/sub] is typically the product of three probabilities: P[sub]3[/sub]*P[sub]4[/sub]*P[sub]6[/sub] for the example. But P[sub]scenario[/sub] for insurance is just P[sub]1[/sub], because it comes up no matter what the player has, and as a result is generally two orders of magnitude higher than all the rest.

Edit: Sorry, I guess subscript tags don't work.

[zengrifter]

It makes NO DIFFERENCE which #decks your indices are run for versus what #decks you play.
6D indices will perform equally at 2D as 2D indices.

Bottom line - one size fits all. zg

[QFIT]

Originally Posted by qwerty

I have used a couple of different programs to create indices based on the type of game I will be playing and seem to be coming up with different numbers which also come up different than some of the Illustrious 18. How should I decide which indices are correct? Was Ill. 18 based on a 6D game? Most of the games I am playing are DD. Which would be a better source, Bj-strat or the strategy file for DD included with Powersim?

Both sources are inaccurate. But, it doesn't make a huge difference.

[qwerty]

Originally Posted by QFIT

Both sources are inaccurate. But, it doesn't make a huge difference.

Haha.. well that clears it up I guess. So can someone tell me what is the most accurate source? :-)

[QFIT]

Originally Posted by qwerty

Haha.. well that clears it up I guess. So can someone tell me what is the most accurate source? :-)

Well, there isn't a set of DD indexes around that I've seen - although any difference, if there is any at all, would be trivial. The set in Blackjack Attack for SD and 6D are accurate (he says having created them. ) But only for the exact circumstances under which they were created. It really doesn't make a big deal of difference unless you can find a deeply dealt DD game. That occurs mostly in my dreams.