New Posts For Thread: System Testing - Sample Sizeshttps://community.betfair.com/general_betting/go/thread/view/94082/28957145/system-testing---sample-sizesAll, I am currently testing a system I have created using small stakes.The system places outright back bets. So far I have placed 215 bets, average odds of 3.4. My net profit (after comm) is 35 points, yielding 16% ROI. Strike rate is 38%.At what poiwell beaten last time out ,drop in class ,1st 2nd fav ,+24 off24 bets 27 days 100%roi, longest losing run 2https://community.betfair.com/general_betting/go/thread/view/94082/28957145/system-testing---sample-sizes?post_id=555097595#555097595well beaten last time out ,drop in class ,1st 2nd fav ,+24 off24 bets 27 days 100%roi, longest losing run 2Tue, 24 Jul 2018 05:53:27 -0500Peter May@PeterMayRacing·6hMy latest blog piece is already on the ATR website. It covers an approach based 3yos in all age handicaps which I referred to in my last book back in 2013. Good to see it still working.https://community.betfair.com/general_betting/go/thread/view/94082/28957145/system-testing---sample-sizes?post_id=554887665#554887665Peter May@PeterMayRacing·6hMy latest blog piece is already on the ATR website. It covers an approach based 3yos in all age handicaps which I referred to in my last book back in 2013. Good to see it still working.Fri, 29 Jun 2018 10:43:43 -0500very interesting thread....i have been tracking a system since the beginning of october 2016. it is based on a very specific set of criteria and is a back betting system. from the start of october to the beginning of May there have been 203 horses thhttps://community.betfair.com/general_betting/go/thread/view/94082/28957145/system-testing---sample-sizes?post_id=552817211#552817211very interesting thread....i have been tracking a system since the beginning of october 2016. it is based on a very specific set of criteria and is a back betting system. from the start of october to the beginning of May there have been 203 horses thThu, 14 Sep 2017 17:10:20 -0500Imagine you are looking back at past races and discover a profitable betting strategy, with a reasonable basis for why it makes sense, and so on. You might have found an edge, fantastic! The problem is, edges tend to disappear over time, as other punhttps://community.betfair.com/general_betting/go/thread/view/94082/28957145/system-testing---sample-sizes?post_id=552513427#552513427Imagine you are looking back at past races and discover a profitable betting strategy, with a reasonable basis for why it makes sense, and so on. You might have found an edge, fantastic! The problem is, edges tend to disappear over time, as other punSun, 06 Aug 2017 10:47:50 -0500I agree with all the points aye robot writes about - it's solid advice. Just to complicate things though, I think it's also possible to have *too large* a sample size and it can give you overconfidence.Imagine you are looking back at past races and dhttps://community.betfair.com/general_betting/go/thread/view/94082/28957145/system-testing---sample-sizes?post_id=552476591#552476591I agree with all the points aye robot writes about - it's solid advice. Just to complicate things though, I think it's also possible to have *too large* a sample size and it can give you overconfidence.Imagine you are looking back at past races and dTue, 01 Aug 2017 09:50:35 -0500I must read this thread in detail as it looks like some people know stuff.For a long time I've been working on pedigrees.At the start of 2017 I wrote programs to analyse pedigrees.My sample size is 159,000.It was a bit of a moment to look at the resuhttps://community.betfair.com/general_betting/go/thread/view/94082/28957145/system-testing---sample-sizes?post_id=552451431#552451431I must read this thread in detail as it looks like some people know stuff.For a long time I've been working on pedigrees.At the start of 2017 I wrote programs to analyse pedigrees.My sample size is 159,000.It was a bit of a moment to look at the resuFri, 28 Jul 2017 10:41:25 -0500Probability is a property of information, not of an event.Agreed which is why using the concept of 'probability' in horse racing and sporting events (even 2 outcome events) is fraught with danger."Chance" is a safer concept to consider---if you are thttps://community.betfair.com/general_betting/go/thread/view/94082/28957145/system-testing---sample-sizes?post_id=552331417#552331417Probability is a property of information, not of an event.Agreed which is why using the concept of 'probability' in horse racing and sporting events (even 2 outcome events) is fraught with danger."Chance" is a safer concept to consider---if you are tWed, 12 Jul 2017 16:59:20 -0500Roughly 2 or 3 hours a day, including putting bets on. Normally up between 7 and 8, turn on the computer and get started. Used to be 4 or 5 hours, but by avoiding races where they are 9-2 plus the field I've cut down the number of races I need to stuhttps://community.betfair.com/general_betting/go/thread/view/94082/28957145/system-testing---sample-sizes?post_id=552331253#552331253Roughly 2 or 3 hours a day, including putting bets on. Normally up between 7 and 8, turn on the computer and get started. Used to be 4 or 5 hours, but by avoiding races where they are 9-2 plus the field I've cut down the number of races I need to stuWed, 12 Jul 2017 16:15:00 -0500McCoy,How many hours "study" would you say you do in a month? I mean, do you work as well as bet? Or are you able to devote all of your time to this?Anyway, on the face of it, I think your 4 or 5% is very realistic and 1583 bets is a decent sample(fohttps://community.betfair.com/general_betting/go/thread/view/94082/28957145/system-testing---sample-sizes?post_id=552331173#552331173McCoy,How many hours "study" would you say you do in a month? I mean, do you work as well as bet? Or are you able to devote all of your time to this?Anyway, on the face of it, I think your 4 or 5% is very realistic and 1583 bets is a decent sample(foWed, 12 Jul 2017 16:03:41 -0500Thanks for your replies.Beginning of 2015 I decided to take things seriously with the horses, after 30 years of failing & subscribed to a ratings/tissue service and started keeping results. At one point I was £12k up, then lost the lot. I finished thttps://community.betfair.com/general_betting/go/thread/view/94082/28957145/system-testing---sample-sizes?post_id=552330791#552330791Thanks for your replies.Beginning of 2015 I decided to take things seriously with the horses, after 30 years of failing & subscribed to a ratings/tissue service and started keeping results. At one point I was £12k up, then lost the lot. I finished tWed, 12 Jul 2017 15:05:05 -0500