1.44 - 4.50 - 6.80 from
sportsbet1,45 - 4,60 - 6,60 from
stakeFirst, I will calculate the bookmaker's margin:
1/1.44 + 1/4.5 + 1/6.8 =~ 1.064
1/1.45 + 1/4.6 + 1/6.6 =~ 1.059
If we assume that the margin is evenly added to each outcome (which is most likely incorrect, since usually there is a bias towards the favorite but it can be ignored now), then fair odds should be:
1.53 - 4.79 - 7.23
1.54 - 4.87 - 6.99
The consensus estimate of the chance of a third outcome would be 7.11, you were able to place a bet with odds of 7.37 and thus received a profit (theoretical) of 3.65%.
This isn't really the right way to look at odds - comparing with the odds at some random moment in time only tells you what the market thinks then, which isn't the most accurate metric. It should be the closing line that you focus on, since the highest limits and the most data is available right before the game starts. This
article from Pinnacle explains the concept of closing odds quite well, and
this article talks a bit more about how pre-closing lines don't give as much information as the closing lines.
If we place a bet at some point in time (for example, the day before the match), then we do not know what the closing line will look like in a day. Therefore, there is nothing wrong with comparing the odds (of our bet) with other odds in the market at the moment - this will give us an idea of how profitable bet we have made. Moreover, at a distance, this information will be correct - because the shift of the coefficients is equally probable both in one direction and in the other direction.
Obviously, the closing line takes into account more data and, hypothetically, it should be more accurate, but the day before we saw the closing line, we do not know what data will appear. We can say that our closing line is the market odds at that point in time at which we made a bet.
The odds for Chelsea vs Southampton had a
closing line from Pinnacle of 1.42 - 4.93 - 7.87. Since buwaytress got lower odds than the closing line
without margin removed (Pinnacle's margin is 3.3% here), it would be reasonable to say that his expected profit from the bet is negative on average.
I don’t think this conclusion is valid for averages. It is correct about a particular case.
buwaytress made a bet and it was clearly profitable according to the calculations. A couple of days later the situation changed (new data appeared) and it turned out that
buwaytress's bet was unprofitable. Does this tell us that he was wrong? No. On average, the situation (new data) will equally likely affect the odds in both directions and in another situation, his bet when new data appears will become much more profitable than at the moment when it was made.
Thanks a lot for the links to the articles, I spent a lot of time thinking about them. Mainly trying to figure out how to prove the author is wrong
In my opinion, the author is mistaken in the methodology in both articles, in the first one regarding the fact that profit, even at a huge distance, speaks of the skill of the bettor. This may be due to other reasons, the most obvious one that comes to my mind is that he was selling obvious unfair coefficients in the market and from a huge number of attempts to sell and a huge number of potential buyers, such sales were sometimes obtained.
The following chart shows the level stakes profit history of real bettor, consisting of 1,214 bets over an 11-week period at the start of 2019, with average betting odds of 2.065 and a profit over turnover of 5.73%.
Does this statistic sound like deep analytical work (15 bets per day, seven days a week)? In my opinion, this is similar to grinding.
How can you keep in your head such a huge amount of information (15 bets every day, which means he knew almost all sports at the pro level) in order to make bets more accurately than the bookmaker? This is unrealistic because the flow of information exceeds human capabilities.
In the second article, I was dumbfounded here:
Are the Fair Odds True?~
It turned out that bookmakers/pinnacles closing line determined the outcome of sporting events with almost 100% accuracy, although he did not write about it directly, but clearly meant and offered "Let’s make a hypothesis: Pinnacle’s closing odds with the margin removed are equal to the true odds."
I think this is counterintuitive and fundamentally wrong. The problem is that it is impossible to prove it analytically (which is why he proposes to accept the hypothesis), since each event that we consider is unique and its true odds are unknown (and will never be known).
Therefore, with a simplified example, I will show how this hypothesis can be wrong.
Let's say we have 50 coins (the coins are symmetrical and we know about it). Obviously if we toss all the coins, the probability of getting Heads is 50% and on average we will get 25 Heads.
Now let's make an example closer to our realities. Let's say the bookmaker has 50 coins. He tosses them up and expects to see 25 Heads. And he gets them on average. But how accurate was his prediction?
For example, the coins were not symmetrical and had the following probabilities:
10 coins have a 30% chance of getting heads
10 coins have a 40% chance of getting heads
10 coins have a 50% chance of getting heads
10 coins have a 60% chance of getting heads
10 coins have a 70% chance of getting heads
The average total toss will be 25 Heads (3 from the first 10 coins, 4 from the second ten, 5 from the third ten, 6 from 4 and 7 from 5). He does not know about the asymmetry of the coins and thinks that his prediction was 100% correct (and the statistics of the tosses seem to confirm this). But we know about the asymmetry of the coins and understand that the bookmaker was right only 20% of the time.
I should note that in my example, the probabilities of getting Heads on coins were distributed linearly, in reality, the distribution law is obviously different (most likely something like a normal distribution), which makes it possible to obtain such beautiful graphs when predicting (as above), but they do not say anything the accuracy of forecasts and proximity to fair odds.
@buwaytressYes, I figured it out. Do I understand correctly that you are trying to place a bet in the first hours of the market appearance on some event, since you are catching odds that will definitely not be effective (close to real) but will be in your favor?