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zabadac

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Everything posted by zabadac

  1. Anyway, as I said in the other thread I have reached a predictivity of 38.5% for the major European leagues. The overall maximum ever observed was 42%, for easy leagues where the home wins were over 50% (Greece of old, Turkey of old). In what sense can we say "easy leagues" and "difficult leagues" ? My experience as a football fun is this: In the 70s-80s I lived sometimes in Greece and sometimes in the UK and I was vsiting the football grounds in both countries. The Greek matches were easy. When the stronger team played at home and scored the opener, the opposition crumbled. Final result 2-0, 3-0, 4-1 was the typical pattern with few exceptions. The English matches were different, to my astonishment as a newbie. Small teams like Carlisle-Sunderland could give a hard time to giants like Liverpool-Leeds. Liverpool's magic mainly prevailed ok, but they had to play for their money. So that's the difference. But 38.5% predictivity is not bad. The question is "do I get my money back from this ?". My present theory is based entirely on elos, which you also have. Your last image says PSG - Bayern Munich 2126-2135. This for me translates into 44.2% for the home win, 26.3% for the draw and 29.5% for the away win. It also says "buy PSG if the price is 2.26 decimal or over", "buy the draw if 3.8 decimal or over", "buy Bayern if 3.39 or over". Suppose I do this, or declare the match a "no bet" if none of the three prices offered meets my criterion. What will be the balance after some trials ? If it is negative it means I 'm not good enough, if it is positive it means I 'm doing well. I have n't started yet. I had some other computer program before to the one I have now and it proved unsatisfactory. But right now I can't do nothing, because of the postponements of course. The thing is can there be any further enhancements and does your software provide any clues ?
  2. Alright, the department stores "Le Mignon" closed in 1998, so it could have been 1990 and I might have backed Costa Rica to win instead of what I said. But the rest of the story is true. As for the football agency, the Costa Rica win probability estimate maybe stood at 20%. My guess was correct because otherwise why did I go and wait for the motorbike draw ? It's 30 years now and I don't keep a diary but i have another experience with department store competitions which is even more weird but unrelated with the present conversation.
  3. Re. my story from 1986, there were no bookies then -at least we did n't have them. And when I said "I went to the betting agents to see ..." I really mean the pools agents, a Greek tote game. But from the various pools systems they had for sale, I could of course see what their thoughts were with respect to that particular match, Scotland v. Costa Rica. Really I would prefer tote rather than bookies. The exchanges are closer to tote, but in any case we are stuck with the bookies. Those fellows then have engaged the services of some famous universities to help them with prediction theories, in case it has escaped you. Nottingham-Belfast-Stanford-Catagna to name but a few. Oxcam too maybe, only I have n't come across any Oxcam papers on footie prediction theory. In sharp contrast all the -rich in other respects- Greek organization in the eighties had in terms of "prediction theory" as I recall, was a table they were obliged to prepare every week and use it to draw draw balls, in case some coupon matches were rained off. This table had the numbers 40-30-30 or 40-40-20 everywhere and people were laughing at it. Rumour had it they employed cabaret actresses loyal to the government party (PASOK) to write down those tables, But they had no reason to become involved, so they did n't care (in those days, now that they offer fixed odds, they do care). So in real life we make our bets with the bookies, we are trying to beat the bookies. What else ? Anyway, you say it can go some of the distance, but you don't call yourself a "Van Gogh". Fair enough, but we need benchmarks in order to work. Everyone needs probability theory benchmarks. Archimedes said "dos moi pa sto kai tan gan kinato", in order to burn the Roman boats. * In my story the moral is that the draw in the Costa Rica v. Scotland match was going to pay me some 10 to 1, 20 to 1 among the shoppers and some 2 to 1 with the agents. So I 'd still be a mediocrity but the prices would be 20 to 1 ! Impossible of course, but in the particular setup it worked like that,
  4. Looks like an impressive piece of sosftware. What is the predictivity value it scores though ? Read about predictivity values and benchmarks here: I don't mean to be critical but I am critical of everything, because our task (to beat the bookies) is difficult, like the legendary hunting for the snark. It depends on this: Who are our opponents ? Let me tell you a story. Summer of 1986, Mexico world cup, early group stage. I go to a large department store for shopping, in Athens-Greece. At the exit they were giving the customers a piece of paper saying "predict todays match and enter our great competition". The prize was a motorbike and the match to guess was Costa Rica v. Scotland. So I thought "everyone will go for Scotland here, they are respected as a European force and they recently beat Greece in the preliminaries, but they have some problems in the scoring department and the Costa Ricans will defend heroically". So I ticked the draw box. The match ended in a goalless draw so next morning I went to the shop to see what happened. What happened was that I was one of only eight who guessed correctly. Did n't win the bike but one among eight was impressive - the number of customers the previous day must have been 1000 and more, it was summer sales period as well. But these people were housewives, girls, grannies and so on. They did n't know about football. So my opponents were weak. If I was to bet against them everyday I would surely make lots of easy money ! In the real world of betting it can never be like that. And indeed after I left the shop when I entered the competition, before going home I went to some football agent shops out of curiosity to see what they thought about Costa Rica versus Scotland. There it was different. The predictions were evenly matched between Scotland and the draw, with some 15% going for Costa Rica to win. So this proves to you then that it is all about the opposition. We want to outclass the bookies like I did with the customers of that department store ! But this is an uphill struggle and although the efforts of the statisticians and software makers are commendable, they should be able to beat some quite difficult benchamrks in order to have any impact.
  5. This is for tomorrow's Fairview (Friday 20-03-2020). It's a different spftware that does the South African cards. I have n't done a South African card for a long time and things seem to have changed somewhat. There is more free material in the South African websites if one wishes to get involved. Also the racinguk.com entries are empty, because they have changed format and their "predictor" is gone. Also Goldcircle.co.za in the first race give no tip.
  6. * Tip: With large fields of 15 or more you should make your win bets with the tote, as the bookies artificially lower the win prices in order to pay the places
  7. Saturday 14 it should say, not Friday. Sorry for the typo. I will try two cards for tomorrow, Dundalk and Fairview and see which one does better.
  8. Not a single one from Wton I see ! I did n't follow them from the start. I made a bet in the penultimate on Moss Gill -as he was very hot fav. In the last I lost.
  9. I came to the forum for the football ratings, but I am also interested in the horses. We seem to have problems now with the virus but some racing has survived, in South Africa and Ireland. I 'm confident nevertheless that in three weeks time the measures taken by the authorities will bear fruit and we are going to see some return to normality. Now about this idea of mine it is based on the method of experts pools. That is people who are employed by governments and industry to give their opinion on certain issues and these opinions are averaged out to reach conclusions. Naturally these people have to be experts in the subject under investigation and they are handpicked. I could do this in football many years ago, that is collect opinions and average them out. But I can't do it any more. Nowadays the internet tipsters no longer give opinions for selected matches or groups of matches. One may advise me to bet on a premiership match, the other picks one from Italy and one from Germany and so on. So I can't figure out how to create a pool of football experts. But the results I had with this in the past were not bad. It was the late eighties or early nineties and we had the pools coupons every week back in those days (I am from Greece). So I could do this pooling and separarte the good sources of information from the bad. That registered an imporvement, but it did n't last long. The newspaper I was doing it for did n't really like it, also others things were happening and the football betting company decided to gradually kill the pools and move towards fixed odds betting. In racing however it is different. The websites who offer a daily card service have to work out all the races without exception. So info of this type can be gathered. It is the French who go for this mainly. There are many websites from France with daily card service, as opposed to 7-8 in the UK. Take a peek here: http://www.turfpronos.fr This is a website that comes out of Morocco and it is dedicated to races of the French PMU system. The guy who runs it is a very knowledgeable and studious and for tomorrow you can take a peek for Turffontein. You can also see how neatly he makes the tables, using saddle numbers always. In every case he says at the bottom "synthese", meaning the result of the averaging process. The idea of "la synthese" is that "the process of aggregation creates a composite tipster who is better than the best tipster of the company". It is not a simple process to find the formula that does this averaging, if you want to be rigorous about it. To calibrate the system first you have to look at the individual contributors. So what is the strength of Racing Post's second choice relative to the first, of the third relative to the second and so on. Once you did that then you have to pit them one against the other. There are some advanced computer algorithms that do that and they come in various names such as "pool aggregation", "probability conflations" and others. You have to effectively find a coefficient of strength for each of the contributors. The top experts gain high coefficients of strength (or indices of strength rather as it is an exponent really), but some gain low coefficients. Who are the "useless", those who give lousy tips that is ? An obvious case of a useless tipster is one who is an idiot. His guesses are random numbers so he does n't count, or should n't count. Another case -which the algorithms manage to identify- is when someone copies from the others and has no opinion of his own. The results of the method in horse racing are not bad. With betfair -which we don't have here- maybe it's in the black. There are the critics also however. They say to me "with what you did you managed to approximate the market or recreate the market so you have n't done nothing really". Well maybe, but here is an example of my work (not the Frecnhman's) from some days ago, before racing stopped:
  10. I have improved the theoretical predictive value of my ratings from 37.5% to 38.5% by restructuring their formula.
  11. That happens too - Shevchenko. But to take any sort of advantage of the early season you have to observe something that happened during the summer. Otherwise ? I don't know what you mean by simple. Scientists say that the more Physics you put in the better. What is true however is I cannot work with data I cannot access. For instance someone tolds me to make ratings based on the total money value of the teams, in millions of pounds. Apart from some discrepancies I see in this, where am I supposed to find this thing tabulated ?
  12. Here is a thing you could do: From your experience give us an approximate ready reckonner for p.l. rating difference v.probability. Using my scale of ratings it goes like this: -200: 20-25-55 -100: 30-30-40 -50: 35-30-35 0: 45-25-30 +50: 55-25-20 +100: 65-20-15 +150: 70-20-10 +200: 75-15-5
  13. Domestic differs from international (national teams) in that the national teams make no transfers. I already observed that the early season offers advantages - if you know the teams that made good transfers. The summer recess is a period where things happen. The players over thirty sometimes reach their limit. Remember Chelsea's Ivanovitch ? He had a great season in 2014-15, the Mourinho championship year. In June he played for Serbia and he was their best player, everybody praised him. Then in August, in the new season, he could n't move a leg. He was 32 and then he realised he lost his form for good and retired. In my opinion Iva was one of the all time Chelsea greats, alongside Drogba, Lampard and Essien. But that was as far as he could go. How you are going to correct your ratings during the summer recess when the teams are not playing, is up to you. But if you do it succesfully then of course it pays, Yet the bet-conservatives I know always say "we never bet early". I 'm somewhere in between.
  14. In my experience the opposite is true. The early season is full of pitfalls. Historic examples: France lose to Iceland in September 1998, soon after they won the world cup. Greece lose to Albania in September 2004, soon after they won the European cup. Other historic example was Leicester who came out of nowhere to win the league three years ago. There is another old statistic of mine. I don't know if it stll holds, it's from the 80s. The teams were finishing level in the first half of the season, 5 or 6 of them, then in the second half of the season one or two distanced themselves to contest the championships. About motivation it's always a must check when we make any bets whatsoever. Would you back Man. City in the return leg against Basel last year, after they had won by four goals to nil in Switzerland ? I don't know about betting against City, but the match was going to be a silly affair. It was obvious. Of course if you know something in advance in the early season about a team that is about to improve a lot, this will pay you. About the ratings -everybody's ratings- I think something is missing. A mystery correction factor. I wrote about world cup 2018 in my first post. So everybody fancied Germany, Germany failed. That was a failure of the elo prediction theory but what stunned me was the other failure, Belgium. Belgium's rating was way below that of the favourites. Why did the pundits then predict Belgium - who as I said performed exceptionally well ? I mean the post, sportinglife, BBC and all the other pundits. Then Liverpool 200 points agead of Atletico. I don't believe that either. 100 maybe. But as I touched on the subjext of motivation here is something you can do: Make some statistics of teams who played without motivation (demonstrably so). Does it pay to oppose them ? I remember a Real Madrid v. CSSKA Sofia match in 2002 I think it was. Real did n't care so it ended in a 1-1 draw. What makes me remember this match is that somebody gambled all his company's money on Real. Then with a short two barreled gun he tried to rob a bank. Then he was taken away in handcuffs !
  15. Except for the Italians all the others played today. But European soccer is over as of tomorrow - European nations cup moved to 2021. Eintracht and the Turks nearly destroyed me. Oly saved me. The match is not over but my bet has won.
  16. I see. But please do it, it will be useful.
  17. Ok the last question. From your past reasults the first one: LEICESTER CITY (65) - ASTON VILLA (-4), result 4-0. Those are NOT the ratings before the game. I can't do nothing with them. Can't I see a table of results with the prediction values ?
  18. Arsenal then are approaching the match against Brighton with 27.5-24.5, Those are what ? Prediction ratings ? And Arsenal against West Ham have been rated for performance with ? If you do have two separate kinds of rating (prediction and performance) they can surely be combined to a single -stronger- rating. You say Arsenal did not play well, ok, we accept that, but if you give them a performance rating other than what comes out of the scorelines then that too is a predictive parameter. Where are the preformance ratings for our two future opponents Arsenal and Brighton ? I don't mean to say you should change the ratings. I have n't even familiarized myself with them in the first place ! Perhaps the way you made them is accurate enough. What I mean is derive a probability scale from them like I did for eloratings.net and clubelo.com. The probability scale gives me a direct relation to the price. So if the probability is 40% then I know that the price must be 2.50 or higher - otherwise it is a lossy proposition. --------------------------------- I mean I could use the page you directed me to. I pick one at random: Oct 27 Norwich City 13, Man United 90, result 1--3 Are those ratings, 13 and 90, drawn before the match or after ? We want before - then it is easy to make the probability formula.
  19. So in the example Newcastle v. Leeds you rated the performance of Newcastle as a 54 and the performance of Leeds as a 15. So explain to me PSG v. Nice now, You say it's 71.25-76 versus 39-37. Is that it ? And as for what it means re. the probable outcome one is supposed to understand, once he has the feeling of the numbers. Correct ? I could work out a probability scale for you though if you give me data. Also handle two ratings (as you seem to work with two ratings) using conflation algorithm.
  20. My estimates for today (Europa league): EINTRACHT - BASEL 60-22-18 BASAKSEHIR - KOBENHAVN 57-23-20 LASK - MUTD 26-29-45 SEVILLA - ROMA 57-23-20 INTER - GETAFE 48-26-22 OLY - WOLVES 35-30-35 RANGERS - LEVERKUSEN 21-26-53 WOLFSBURG - SHAKTHAR 41-29-30 Some of those are posponed. Looking at bookie prices also, marginal value bets are: SEVILLA OLY (but difficult) LEVERKUSEN Also I like EINTRACHT with hcp -1, BASAKSEHIR with hcp -1.
  21. Thank you for the welcome. I don't seem to quite understand how you are doing things here, so let me try you with examples. Let's take Paris Saint Germain and let's look at clubelo.com first who are using the classical elo theory. PSG are playing Nice at home next. For PSG he says: Match -1, ELO = 1875, beat Dijon 4-0, goes to 1877 Last match, ELO = 1877, beat Dortmund 2-0, goes to 1895 For Nice he says: Match -1, ELO = 1592, drew against Bordeaux 1-1, goes to 1593 Last match, ELO = 1593, beat Monaco 2-1, goes to 1605 So we have now PSG = 1895, Nice = 1605. It's a big difference, 295 points, so the prob. of PSG winning looks like a 95%, but that's not important. Even the 95% values we should be able to compute with accuracy. Now in your French Ligue 1 page you give two sets of figures: PSG 71.25 and 76 NICE 39 and 37 and we are supposed to judge things from those. It's a different scale you are using obviously, but what are the two numbers for each team and how are they derived ? You are talking about prediction ratings and performance ratings but I have n't quite understood. Is the prediction rating the classical elo expressed in a different scale to the usual and is the performance rating something else ? How can you follow all the teams of the world re. performance and how can you judge ? Re. performance let me give you an example where our opinions probably clash. Chelsea beats Everton 4-0 last Saturday (a match I watched). I believe Everton was very poor in defense rather than Chelsea improved. I don't know how to rate Chelsea exactly -other than by the classical (Russian) method- but not really. Can you explain to me your figures a bit further and are you prepared to go into the business of detailed calibration ? My objective is of course to have the 37.5% figure I quote in the first post beaten. We may call the 37.5% "the clubelo performance figure" though it's not really their official performance figure, it's mine, as an interpreter.
  22. Yesterday with my formula: PSG - Borussia 48-26-26, no value bet Liverpool - Atletivo 73-18-9, value bet but at low price (L'pool won in normal time). You could call Borussia's away win a value bet if the price was over 4.00 (3/1) - I don't recall. But I generally don't go for third chances value bet or not.
  23. I 'm a new member and I 'm interested in the use of elo ratings to predict football results. I encountered them first on this site: http://eloratings.net/about Using their elo ratings and a sample of matches I made some calibrations to extract a mathematical formula that transforms the elo difference to probabilities for home, draw and away. That was back in 2014, for the Brazil world cup. I can write the formula down for you if you are interested, but I also want to discuss with you the probable merit of such formulas. First our objective should be to locate value bets, meaning matches in which the bookies pay more that fair. So if the probability based on the elos works out to be 50% and the price is 2.50, it is a value bet. If the price is 1.80 then it is n't. Naturally you will say this to me (or you should ask !): When the price is 2.50 did you check out that nothing unusual is going on, such as key player injuries or many substitutes in the squad or something like that ? Of course I must do that, is my answer and suppose things are ok. Another thing you should ask is "ok, but is your formula true ?". Fact is anyone -human or computer program- can say "the home win probability is 50% and hence and so on and so forth" but is it true ? How can we be sure ? This is where information theory comes into play. My formula should have higher information content or at least equal to that of the bookies. When you see bookie prices x-y-z then you convert those to probabilities by doing this: home = (1/x) / (1/x +1/y + 1/z) = P1 say draw = (1/y) / (1/x +1/y + 1/z) = P2 say away = (1/z) / (1/x +1/y + 1/z) = P3 say Then suppose the match is played and the result is a home win. This contributes to the bookies predictivity the value A1 = P1. Another match is played and the result is some other result and adds the value A2 = the P2 value of the new match say. The compound bookie predictivity from the two matches is A1 x A2. After many matches it becomes Q = a1 x a2 x a3 x ... x An Your computer cannot carrry out this operation because the product of many such numbers that are less than 1 will become zero. But you take logs and you take the average of the log sum: I = SUM OF LOG(Ai) / n You then take the exp of I, to end up out with some familiar numbers (percentages): Predictivity = exp (sum of log(A) / sample size) The predictivity ranges from 1/3 to 1. 1/3 means no predictivity really, random guesses. 1 means he knows everything in advance The usual bookie predictivities are of the order of 37-39% in the major European leagues. So, all this talk about predictivity to verify that my formula -or your formula- based on the elos is true or not. My formula has a predictivity value too, computed in the same way as for the bookies. Must hold therefore: Porgnosticator's formula predictivity >= Bookie predictivity Otherwise the formula is suspect, can't be considered true. Now what did my formula do ? My measured predictivity was 37.5%. So maybe it works - just maybe. I started with the elo ratings and ended up with a probability calculator. But there are more sites offering elo ratings. Yours for example and also the known http://clubelo.com/. I don't have predictivity values for all of them -they don't publish or they don't know how to do it. So what I 'm searching is which one is the best ? There is also the basic theory of the elo ratings. This is described here: http://eloratings.net/about This looks ok but have the various coefficients used in it been computed with the scheme I describe above. To make the predictivity -looking backwards- maximum ? These are the issues I am confronted with and I 'd like to have your opinion. There are some oddities I have observed. One that striked me was during the 2018 world cup. In the beginning the elos showed Brazil and Germany at the 2000 mark. France at about 1900 and Belgium at about 1800. That's ok you could say. France won it, it was n't out of the blue really. But I 'm talking about Belgium. Belgium played very well and nearly won it (n.b. the true final was the semi France v. Belgium). The thing is Belgium 200 pts below the favourites counts as a big surprise. So ok surprises happen you might also say and I might agree. But was it a surprise ? All the pundits were rooting for Belgium before the start of the tournament. Brazil-Germany first, ok, but their third choice was Belgium. So we have a case in which the elo values are ignored by the pundits and the pundits are right (as Belgium was a great team). This kind of thing speaks against the elo theory imho. What are your views ?