Newcastle to score 2+ goals and 6+ corners
Q) How can we estimate the above?
A) With great difficulty. It is an extremely complex problem.
The probability of a team to score goals is not independent from the probability of a team to take corners. In some scenarios, more goals will count negatively towards expected corners, and in some scenarios it will count positively. There is a point of dominance in a game where a team has so much possession, more corners relate to more goals. However when possession is more balanced the opposite is true. It is extremely difficult to estimate this with any precision. The bookmakers themselves don’t agree: one bookmaker will lengthen the odds of Team x Goals X Team y Corners, whilst another will shorten the exact same components. The co-efficient appied to dominance can shorten or lengthen the straight multiplication by +/- 40%.
We therefore have two options to estimate the above:
(1) Easy solution – p(Newcastle to score 2+ goals) x p(Newcastle to score 6+ corners)
(2) Complex solution – p(Newcastle to score 2+ goals) x p(Newcastle to score 6+ corners) x (co-efficient of dominance)
We use (1) when we are looking at a large number of bets. However if we’re looking at a single bet, we can use (2) and spend time assessing past games, form, large data etc. to come up with our own estimates of a coefficient based on possession dominance, and then shorten or lengthen the odds based on these findings. I did some back-testing analyses which suggested the bookmakers are too pessimistic; they push the odds out too far when they lengthen, and they don’t shorten enough when dominance has reached.
Over a large number of bets (thousands over the year), one option is to use Occams Razor (simply use corners x goals) as (1) this is fast when putting thousands of bets on the tracker each week, (2) accuracy of a large data set will converge to pessimism and (3) I need to admit to myself that there are many occasions where I simply don’t know if the odds should be pushed out or pulled in – and neither do the bookmakers (proof below)
It’s such a complex, difficult question I’m glad to see discussion on the hypothesis channel as it will be interesting to see a balance of opinion. bookiebashing has put in > 12 months of research into inclusivity coefficients, which will feature in a calculator later in the year.
Example of difference of opinion in Dominance
Bet365 price up Man City over 5 goals at 11 and Man City over 10 corners at 5.5. They shorten the odds of the multiple as they believe that one is more likely to occur with the other.
Betfair prices up Man City over 5 goals at 10 and Man City over 10 corners at 5.5 in the same game. They lengthen the odds of the multiple as they believe that one is less likely to occur with the other.