Forum Archive : Terminology

"Equity", "volatility", "claim", "market" From:   Erik Gravgaard Address:   erikg@inet.uni-c.dk Date:   5 June 1995 Subject:   Re: glossary needed Forum:   rec.games.backgammon Google:   3qv28i$htm@news.uni-c.dk John B Kelly wrote: > I've read the FAQ, a couple of backgammon books, and this > news group for quite awhile, and there are still some words I > don't quite understand. And I bet some other readers might like > these words clarified. It might also be a good idea to talk > about them in the FAQ. The terms are EQUITY, when it is paired > with other words like shot equity, racing equity, cubeless > equity, match equity, etc; VOLATILITY, often used as low or high > volatility regarding a position and whether to double; CLAIM, > which refers I think to the point when someone should double, but > I'm not sure; MARKET, as in having a market or losing one's > market, again referring to the precise moment to double; if I > remember correctly: LOW VARIANCE, which I have no idea what that > meant. I'll give it a try. Some of my explanations might not be accurate enough, and they might not even be correct, but I am sure that errors will be corrected be the many experts. EQUITY The easy explanation is that it is VALUE. Meaning that the equity in a position will be a number (positive if you are the favourite, and your opponent will in that case have the negative value as his equity, as it has to add up). The number (for instance + 0,655) represents the number of net points your position is worth. The calculation is made by multiplying the probabilities of an occurence with the appropriate number of points won or lost, and then adding all the values together to reach the final net value, the Equity. SHOT EQUITY As I see it, it depends on the context, but I suppose that it often relates to the shot probability. It could however also be the equity (as described above), when only looking at the immidiate or long term shoot possibilities. RACING EQUITY The equity (as described above), when only looking at the non contact game. Usually one would try to seperate the assessments (Shot E. and Racing E.) and then add them up afterwards. Mostly because it makes the mental task easyer. MATCH EQUITY Simply a question of setting the goal line. In equity (as described above) one looks at one game only, and the equity is points as the goal should be to win as many points as possible. But when you are playing a match your goal is not to win as many points as possible (for instance in a 5 point match it doesn't matter if you win 16-0 or 5-4) instead you are aiming at winning the match - and just that. So now your equity is all about the match winning chances, and your equity will be a value between 0 and 1. CUBELESS EQUITY Does only apply when we are dealing with a match. In this case for different reasons the cube might have lost it's potential (for instance at match score 4-4 to 5 or 3-3 to 5 with the cube allready on "2"). In these cases the game will have to played to the end as the cube cannot end the game. Again one could try to seperate the calculations and first try to view the position "cubeless" as it does simplify the assessment somewhat, and then afterwards one could try add or correct for the cube and the influence the cube has (if it is still alive). VOLATILITY The nature of the position. In other words: How likely is it to see a big swing in the position, making a big difference in the equity on the next rolls (for both players). Normally the volatility is an issue when deciding to double or not. As one would like to double at the optimal point giving the maximum effect with the minimum risk, it is important to look out for how likely it is that you might loose your market (see below) and by how much. With a high volatility one would double earlier than with a low volatility, where you would try to make your slow advance to the optimal point of doubling. CLAIM You are claiming when you are offering a double, that your opponent should drop (or at least he should drop in your view). Normally one would talk about claiming when estimating to play on for the gammon vs. claiming. MARKET To loose your market is to miss the chance of your opponent to take the cube (accept the doubling). As stated above you would like to offer the best possible double (the one that hurts your opponent the most), but in the attempt you might "wait too long" so that your opponent has an "easy drop". Normally one would try to look for "Market Loosers" when one is thinking about not doubling. If you can find no Market Loosers (and remember that you should look at both your own roll and your opponents) you can wait with the doubling as you have lost nothing by not doubling - with no Market Loosers" you can allways double at the next turn (if it still looks favourable). Erik Gravgaard Pres. of the Danish Backgammon Federation   Did you find the information in this article useful?           Do you have any comments you'd like to add?

 

Terminology

Alphabet soup  (Tom Keith, Apr 2004) 

"Anchor and guard" position  (Chase+, Apr 2010) 

"Back game"  (Marty Storer, Jan 2004) 

"Baffle box"  (garyo+, Mar 2005) 

"Bagai position"  (Timothy Chow, Dec 2012) 

"Banana split"  (Rich Munitz+, June 2011) 

"Banana split"  (Adam Stocks+, Sept 2004) 

"Beavers"  (Sander van Rijnswou, May 1999) 

"Beavers"  (Shuman Lloyd Lee, Aug 1991) 

"Blunder", "whopper"  (Raccoon+, July 2005) 

"Bot"  (Pit Bull+, Mar 2004) 

"Bronstein" clock setting  (rew+, Sept 2012) 

"Calcutta auction"  (Roland Scheicher+, Dec 2001) 

"Chouette"  (Roland Scheicher+, Mar 2002) 

"Cube provocation play"  (Chuck Bower+, Apr 2007) 

"Dance"  (William R. Tallmadge, May 1998) 

"Dropper"  (Robert D. Johnson, Sept 1996) 

"Duplication" and "diversification"  (Simon Woodhead, Nov 1991) 

"Equity"  (Gregg Cattanach, Aug 2000) 

"Equity"  (Gary Wong, Dec 1998) 

"Equity"  (Chuck Bower, Oct 1996) 

"Equity"  (Michael J. Zehr, Mar 1996) 

"Equity", "volatility", "claim", "market"  (Erik Gravgaard, June 1995) 

"Freeroll"  (montygram, Nov 2005) 

"Gammon price"  (Ron Karr, Aug 1996) 

"Gammon rate", "gammon price"  (David Montgomery, June 1995) 

"Gammon-go" (GG) and "gammon-save" (GS)  (Mary Hickey, Feb 2004) 

"Gammon-go" (GG) and "gammon-save" (GS)  (Marty Storer, Oct 2002) 

"Gammon-go" (GG)   (Chuck Bower, Jan 2004) 

"Golden point"  (Daniel Murphy, Dec 2004) 

"Holding game"  (Alan Webb+, Dec 1998) 

"In the box"  (Ken Bame+, Sept 2012) 

International phrase dictionary  (David Allen Sorensen, Sept 1997) 

"Joker"  (Richard Divdesman, Sept 1998) 

"Kamikaze play"  (Bill Patterson+, June 2011) 

"Kauder paradox"  (Carl Tait+, Nov 1995) 

"Latto paradox"  (Jean-Pierre Seiman+, July 2004) 

"Lose your market"  (Shuman Lloyd Lee+, Aug 1991) 

"MCV"  (Mislav Radica+, Oct 2009) 

"PRaT"  (Raccoon+, Jan 2007) 

"Phantom double hit"  (Marty Storer, May 2010) 

"Polish prime"  (Jason Lee+, Jan 2006) 

"Pure play"  (Daniel Murphy, Nov 2000) 

"Pure play"  (Casey Forrest+, Feb 1996) 

"Raccoon"  (Steven Keats, Feb 2011) 

"Root number"  (Ken Bame, June 2004) 

"Russian Bridges"  (leobueno+, Mar 2013) 

"Short play"  (AJ+, July 2012) 

"Speed board"  (Gregg Cattanach, June 2004) 

"Splot"  (mamabear, Apr 2007) 

"Squeeze", "trap play"  (Philippe Michel+, Feb 1997) 

"Suicide play"  (Brian Sheppard, Aug 1997) 

"Swing tournament"  (Carlo Melzi+, Mar 2006) 

"Table stakes"  (Carlo Melzi, Sept 2002) 

"Technical play"  (Adam Stocks+, July 2002) 

"Thematic"  (Beauregard+, Aug 2009) 

"Thorp count"  (Stephen Turner, June 1996) 

"Time," "timing," "checker," "dancing"  (Marty Storer, Apr 1992) 

Turkish names for rolls  (Lars Soezueer, Mar 1997) 

"Vigorish"  (Anthony R Wuersch, Feb 1995) 

"Volatility"  (Michael J. Zehr, June 1998) 

"Wash"  (Hardy Hübener+, Sept 2004) 

"Wash"  (Brian Sheppard, July 1997) 

"Weaver"  (Alan Webb+, May 2000) 

"Zone" of attack  (Matt Reklaitis+, Dec 2007) 

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