Can some one please explain to me how to work out your edge? (I am NOT saying I have one)

I guess there must be some kind of formula based on units won in x amount of bets divided by amount of numbers covered ( I am probably miles out here lol)  ..... or something like that.
Would really appreciate some help with this.

For roulette it's not so complicated.

The EV for an even chance is (chance of winning v chance of losing), where 1 is your stake.

(18/37 * 1) + (19/37 * - 1) = 18/37 - 19/37 = -0.027 * 100 = -2.70%

Any odds in single zero roulette will return -0.027 EV.

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To test your own bet selection, you first need to calculate your probability of winning a single bet by simulating it across an adequate sample size, ie 10,000 bets.
You can then calculate the expected value suggested by the results. If there is an edge, your probability of winning an even chance would be higher. You can simplify to this:

(0.51 - 0.49) = 0.02 * 100 = 2%

Again that is chance of winning v chance of losing.

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Calculating the EV for sports is a bit more complicated.
The official way does involve factoring in your potential winnings and losses. I'll quote from a useful article.

Quote

The formula for calculating Expected Value is relatively easy – simply multiply your probability of winning with the amount you could win per bet, and subtract the probability of losing multiplied by the amount lost per bet:
(Probability of Wining) x (Amount Won per Bet) – (Probability of Losing) x (Amount Lost per Bet)
To calculate the expected value for sports betting, you can fill in the above formula with decimals odds with a few calculations:
1. Find the decimal odds for each outcome (win, lose, draw)
2. Calculate the potential winnings for each outcome by multiplying your stake by the decimal, and then subtract the stake.
3. Divide 1 by the odds of an outcome to calculate the probability of that outcome
4. Substitute this information into the above formula.
For example, when Manchester United (1.263) play Wigan (13.500), with a draw at 6.500, a bet of $10 on Wigan to win would provide potential winnings of $125, with the probability of that happening at 0.074 or 7.4%.
The probability of this outcome not occurring is the sum of Man Utd and a draw, or 0.792 + 0.154 = 0.946. The amount lost per bet is the initial wager – $10. Therefore the complete formula looks like:
(0.074 x $125) – (0.946 x $10) = -$0.20
The EV is negative for this bet, suggesting that you will lose an average of $0.20 for every $10 staked.

Fantastic Number Six. Thank you for your reply.

I don't know if it's for academic reasons or if you think you have an edge, but it's worth noting a few points anyway.

Firstly, it's impossible to gain an advantage with a roulette system, old news I know.

The system would obviously have to be simulated with flat bets, or even without any betting, as long as you end up knowing the overall strike rate. A strike rate above the expected may suggest an edge. After that you can use the z-score to find out the probability of whether the results are due to luck or something else. While the house edge would simply undermine the premise behind any bet selection, it's feasible to think you don't need an edge to win consistently, which gives hope for a holy grail system. With a long simulation you can test for a few vital bits of data (you can't get these testing real play small sessions). Mainly you can ascertain, officially or not, the variance and volatility. There are formulas for that, but they may produce a number that can't be interpreted. You can look at the variance as how far your strike rate differs from the expected; you can look at losing runs and how the strike rate dips at those moments it performs badly. And the volatility is how that variance would affect your bankroll; you can discover the max drawdown and tell whether the system is economical and what kind of bankroll you need. In short you could gauge variance and volatility without calculating it and still tell if your system has any kind of merit, or if you're going to go bust as soon as you start playing. If the variance is low, there's no reason not to think you can't play through it with some kind of grinding progression because, having tested it thoroughly, you would know that it's likely to recover quite quickly. Contrast that with not testing a system properly, most players don't know the volatility and go bust in their first serious drawdown.

Bayes had written some good stuff that I actually just posted the other day on the other forum just to bring it up to forefront a little...it might be worth a gander
http://www.rouletteforum.cc/index.php?topic=1093.0

Quote from: Number Six on August 18, 2013, 05:56:33 PM
I don't know if it's for academic reasons or if you think you have an edge, but it's worth noting a few points anyway.

Firstly, it's impossible to gain an advantage with a roulette system, old news I know.

The system would obviously have to be simulated with flat bets, or even without any betting, as long as you end up knowing the overall strike rate. A strike rate above the expected may suggest an edge. After that you can use the z-score to find out the probability of whether the results are due to luck or something else. While the house edge would simply undermine the premise behind any bet selection, it's feasible to think you don't need an edge to win consistently, which gives hope for a holy grail system. With a long simulation you can test for a few vital bits of data (you can't get these testing real play small sessions). Mainly you can ascertain, officially or not, the variance and volatility. There are formulas for that, but they may produce a number that can't be interpreted. You can look at the variance as how far your strike rate differs from the expected; you can look at losing runs and how the strike rate dips at those moments it performs badly. And the volatility is how that variance would affect your bankroll; you can discover the max drawdown and tell whether the system is economical and what kind of bankroll you need. In short you could gauge variance and volatility without calculating it and still tell if your system has any kind of merit, or if you're going to go bust as soon as you start playing. If the variance is low, there's no reason not to think you can't play through it with some kind of grinding progression because, having tested it thoroughly, you would know that it's likely to recover quite quickly. Contrast that with not testing a system properly, most players don't know the volatility and go bust in their first serious drawdown.

Very well written ...

Thank you all for your input, I really appreciate it.

[quote auAt or=Blood Angel link=topic=2299.msg19022#msg19022 date=1376832337]
Can some one please explain to me how to work out your edge? (I am NOT saying I have one)

I guess there must be some kind of formula based on units won in x amount of bets divided by amount of numbers covered ( I am probably miles out here lol)  ..... or something like that.
Would really appreciate some help with this.
[/quote]
First, you must cut out random fluctuations
Then, establish that your play is not random
You need at least 4sd  to start
It is a hard task to determine your exact edge

Thanks for re-surfacing this excellent thread  Whybot. There is some excellent work here.

There is a thread on the General Discussion page for May this year which features useful fresh input from Sqzbox, Xander and some questions from myself on the subject of How Do We Define and Calculate The Edge.in roulette.