how do u measure ur edge?

not sure, but doesnt a bookie measure his edge based on overround, or a casino basing theres only paying 35/1?

candiru, i understand that  u can calculate ur eadge by the difference in probablity of the actual event and the price implied probality. however inmy case i bet on quite a wide range of things and most of the time it is in play so some of my positions will lose at the end eventhough i might end up with a profit and found it dificult to analyze in terms of counting my loss and win. i was asking if there are any tools or ideas to check ur edge interms of more higher level parameters such as profit and loss vs stake or something else without going into the detail of each bets.

good question, but my knowledge ends there im afraid, soz cant help

thanks divide

trying to calculate an edge in chance prediction is rather like trying to use a serpant to draw a straight line as although we understand the creature to be very long and thin, it is never the same animal twice in shape.

What you do with your serpant in the privacy of your own home is your own affair.

Racing guru your method assumes that everyone who makes a profit has an edge.

As jonnytheguesser will tel you, there are so many punters on here that many punters will make a profit, even over a year, without any edge at all.

That isn't to say that no winning punters have an edge, just that they might make up a minority of those with a profit.

Many people who are in profit were simply the lucky ones. In such a large population there will always be outliers who look lucky or unlucky.

So it would be better to put a confidence interval around your edge. In other words, what is the worst your edge could be before you'd be unlikely to have made a profit and what is the best it could be before you'd be unlikely to have made so little.

This can be calculated but requires odds for each bet you made.

I believe % of turnover is the best measure.
After all if you bet on everything day in day out, with no selectivity at all, you will lose somewhere between 2-8% of turnover, after comm. ( depends a bit on the bet type).
So if you add in some selectivity( that is your secret edge ) and can turn this % into positive territory ( over a reasonably large sample as trevh refers to), then you have effectively quantified your edge imo.

I'm not so sure. Put 100,000 monkeys on a Betfair like site and by year end some will be in profit, indeed many will be in profit, even if most will be in a loss.

Profit alone cannot determine whether you have an edge. You need to construct confidence intervals as I said.

If you've made millions of bets then this interval should be very narrow!

ror
You may not be a monkey, but you sure starting to sound like a turkey.
You may be the classic case of overanalysis, to the point of paralysis.
You have admitted you don't bet a lot and if and when you do you only bet in very small amounts.
This basic inexperince imo disqualifies a lot of your " academic" observations.
All you say and post is perhaps fine in some ivory tower academic world, but not in the BF world imho.
Nothing personal meant of course.

I agree with Frog Hair.
Betfair is not a blackboard, a text book, nor a calculator.
There is no way on earth, that anyone that bets constantly can not have an edge.
There may be a couple of people who have ten bets all year and got on a lucky streak, otherwise it's nonsense.
Betfair is fundamentally outsmarting the opposition and commission, it takes one hell of an edge to do that consistently if you're a backer or a layer.
Then there's the stable insiders, the fast pictures, the market makers, and some savvy traders who have an edge before they even start for the day.
However, the vast majority have no edge at all and swing from method to method being eaten alive by commission.

The OP has already been answered.
Calculate profit divided by turnover as a profit percentage.

Cat - agree to some extent but when you have a big sample size you'll be surprised how little it varies. I have data for over 8 years and pretty much know that I'll make x% to stake +/- 3% per year. It is useful to know as helps you to up your stakes with confidence.

ror, i think it is possible to quantify ur edge. but it has to be clearly defined. ur edge coressponds to the profitablity of a particular set of actions or  predictions  on a set events in the long run. for example if we consider fottball, ur edge may coresspond to ur ability to predict a result in particular teams match result, goal results, or it can be corresponding to something in a particular league. else ur edge may coresspond to a particular sport in general or a  market. if u make a profit overall and dont know ur edge it is only because  u havet bothered to think about it and define and measure it. that said,in almost all cases somebody who makes a profit long term will clearly know which bets are more likely to make a win or a loss, hence an edge, eventhough he doesnt want to say he has an edge.

some people have mentioned profit over turnover as a measure. however i dont have a clue how turnover is used in a betting sense. what do u mean by turnover?

It's a bit wishy washy with gambling, especially because of trading out etc. It can be defined in a couple of senses depending if you're a trader or not.

Turnover is your total liability across all bets, both those that won and those that lost. (Total amount staked.)

or

Turnover is your gross winnings. (income)

If you made 2 bets on evens shots staking 1@2.1 (So you have a clearly defined edge), and one of them came in, then your profit is 1.1*09.5-1 = 0.045

But your turnover is 1.1*0.95 = 1.045

By racing guru's calculations this is a 4.3% edge.

as i said traders are a different breed and can count what they want

Does it matter at all how you personally define/quantify turnover ?.
As one is presumably only using it to compare your internal performance over time, that is is it improving or deteriorating or staying constant, all that matters is that you use a consistent form of measure.
That is you compare oranges to oranges and apples to aplles.
If, however, you are comparing it to some external norm, then obviously you need to know exactly how the norm defines turnover.
But that's not what is being debated here is it ?

ror
Please stop looking for bogey men in everything.
You're way too over-theorising everything believe me.
You're adding complications onto complications for no good practical end purpose.

As I said the point is about measuring your own edge is for internal performance comparison purpose, not for some theoretical external bragging or any other purpose. It's not about my edge is bigger than your edge, or anything like that, is it ?
I don't care how anybody measures their particular edge, it makes no difference to the way I define, measure and PRACTICALLY use that info. for my own internal purposes.