1. #1
    Stocks
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    What math could I use for this

    I was looking at last years hockey results using percent of goals scored verses win% and I thought this was kind of interesting. Its like the results went up like a curve.

    Heres some result to show what I'm talking about

    First number is a teams percent of goals scored in a game like if there was 5 goals scored in a game and team A scored 3 then they would have scored 60% .

    Second number is win%

    58% = 66%
    54% = 59%
    50% = 50%
    47% = 43%
    43% = 33%

    I did it for all the teams last season and the results were similar so it difinitly shows that both are relavent.

    Something interesting the top team Washington scored 58% of the goals in games they played and had a 66 win % while the worst team was Edmonton who only scored 43% of goals in games they played and had a 33 win % thats almost the exact opposite.

    Anyway what kind of math or method could I use here to get a win% for a game if I can already predict a score.

    Thanks

  2. #2
    subs
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    i'm pretty new so sorry but i don't get it - if you can predict a score then why do you need a win %, you already know. but this is common sense if you score more goals in games then you win more games. but it does not mean that you can predict future scores with more accuracy then the people setting the line.

    what you need to do is back test to see if this system will win you money (good luck with this). find the closers and see if you would have won or not over a season.

    you may wish to add
    home ice advantage
    strength of schedule
    injuries
    just to name a few.
    BOL
    Last edited by subs; 11-17-10 at 10:53 PM.

  3. #3
    Stocks
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    What I'm looking at here is if I can predict a score and then turn that into a win% then I can turn it into a moneyline.

    So if I predict a score to be

    Washington 3.8
    Montreal 2.7

    Washington scored 58% of the goals so that would make them 66% change of winning and then we could turn that into a moneyline -200

    And we can account for any other factors like home ice advnage and what not into the predicted score.

    What I'm saying about the relationship between % of goals scored in a game verses win% is that its like a sliding scale where the higher the % of goals scored the winning percent goes up exponentially.

    So is pythagrom the way to go here?

    pythagrom gets very close to win% based off the goals scored I can mess with the exponent a bit.


    On to the predicted score see if I got this right.

    If the league average is 2.77 goals per game.

    Boston scores 2.9 goals per game while giving up 2.2 per game

    And they're facing

    Montreal scores 2.4 goals per game while giving up 2.6 per game

    This is not going to take into account home ice or current form or anthing else

    To find the predicted score do I find the difference between each teams goals scored for and against verses the league average.

    Boston scores .13 goals more and gives up .57 goals less then the league average
    Montreal scores .37 goals less and gives up .17 goals less then the league average

    So for Bostons score you would add they're goals scored and montreal goals against to the league average and do the same for montreal.

    Boston 2.77 + .13 -.17 = 2.73
    Montreal 2.77 -.37 -.57 = 1.83

    Predicted score

    Boston 2.73
    Montreal 1.83

    Using pythagrom

    Boston 68.9%
    Montral 31.1%

    Moneyline

    Boston -222
    Montreal +222

  4. #4
    subs
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    ok since no 1 else is helping and if i screw this up some1 might want to flame me and help stocks out, i'll give my $0.02 worth here.

    there are 2 ways of looking at this:

    1/ (OffBos * DefMon)/LeagueAverage

    (2.9 * 2.6)/2.77 = 2.72 BOSTON

    (2.4 * 2.2)/2.77 = 1.9 MONTREAL

    2/ OffBos + DefMon - LeagueAverage which is what you did. i think both are right. hopefully some1 better than me can tell us which is better but maybe an average of the 2 numbers would be best?

    2.9 + 2.6 - 2.77 = 2.73 BOSTON
    2.4 + 2.2 - 2.77 = 1.83 MONTREAL

    So this is where i prolly get it wrong but i used the 2 variable poisson calculator in the tools.
    ok using 2 variable poisson distribution i type 2.73 into event1 expectation and 1.83 into event 2 expectation and i get.

    57.0% for win -133
    25.1% for loss +298
    17.8% for push +462

    hope this is right and i'm not confusing the issue more. these do not add to 100% because of rounding and i approximated the lines from the %. please remember this is the no-vig line.

    hope this helps. having said all this i'm not sure what you have found here. yea for sure the team that scores more points than its opponents wins more games and vice versa. how this is helpful not sure. if you test this going back to seasons before i am pretty sure you will find a net loss but i'm a rookie really so please check it all out for yourself.

    good luck buddy

  5. #5
    Stocks
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    Thanks Subs

    I'm not sure about which of the 2 methods of predicting the score is right, I like yours better as it would fit into excel a lot better but I'll porobably end up trying both unless someone else wants to chime in on the situation.

    As for the next part I dont know if poisson will work or not but I have been looking into Pythagorean which is showing a lot of promise. I got a few ideas to test this that I'll try tomorrow.

    My theory for all this is if you can accurately predict a score of a hockey game its very much relavent to win% which you can then convert into a moneyline and find value.

    I'll post results tomorrow

    Thanks man

  6. #6
    subs
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    i know nothing about hockey but i know that in college basketball a guy called ken pomeroy does free public modeling, which is really deep. i have been told that these are not great but can be very useful for futures bets. how many games will a team win over a season type stuff. apparently this is an easier market to attack. it has lower limits to reflect this.

    good luck Stocks.

  7. #7
    Stocks
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    Heres some results using last season stats

    I compared a team win% to goal% using Pythagorean with an exponent of 2 for the goals.

    The win% was equal to or off by just 1 or 2 percent of the goal% for most teams.

    An example of what I'm talking about is

    Washington won 66% of they're games while scoring 3.82 goals per game and allowing 2.77 goals per game and using pythagorean equals 66%

    This was the kind of results for most teams. A couple were way off like Phoenix and Nashville

    Phoenix won 61% of its games 54% for goals but looking at the results from last season they ended the season on a nice hot streak going 13-5 with 9 games going to a shootout so they won a lot of 1 goal games and thats the reason why they're numbers are off same with Nashville. Now this could be corrected atleast a little bit by using current form as part of your predicted score.

    I also looked at 20 teams results just using home game stats and although the results showed promise they were'nt as good as the overall stats. There were still a lot of teams that were right on like Detroit who won 61% of they're home games and got 61% goals. Phoenix and Nashville were off aswell but other teams like Washington and Chicago who were exact using overall preformance but were off using just the home stats.

    I still think this has some promise I may start testing it this season at around the 20 game mark and see what happens.

    By the way to get the predicted score I would use

    Strength of schedule
    Home/away goals
    Overall goals
    Last 5 games goals
    Starting goalie

  8. #8
    uva3021
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    find the correlation between goals per shots and winning percentage, maybe from last 5-10 years of data, then you can extrapolate winning percentage from where a team's goals per shots falls on the least squares fit line

    use the excel function "Forecast"

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