Ratings Help(Excel)

[JRT]

Hi Guys

Trying to develop some ratings to produce Average goal expectencies for each game, and I am running into problems when using Excell.

I use the solver function to give me my best fit of ratings taking into account past games, using Team A Off - Team B Def = Team A Exp. and veice versa.

My problem is that in some cases I am generating negative expectencies, i.e. Team B Def is greater than Team A Off.

I have basic statistical knowledge and reckon I need to alter the Iterations section in the solver, but have no idea what I should be doing to help my specific problems.

I have just read the Poisson help thread and reckon some people here might be able to give me some help.

Thanks in advance
JRT

[plez]

Hi JRT - I must have used Excel every working day for the last 8+ years and I'd never heard of the Solver :o ! If others can help you with that specifically then go with that, otherwise I would be willing to help, but I'd need a bit more information about what exactly you are trying to do!

[thephysician]

I'm confused too, but too my mind, a teams Offensive goals scored takes into account the average defence it already has played against, so merely subtracting the defense doesn't give a good expected goal rate.... after all for every goal scored, someone's let one in so there would be a net-total of 0 goals scored each week using that sort of model!

Prehaps I've missed the details? I'm happy to have a look over any spreadsheets you have...

[muppet77]

do you mean
average goals scored by A - average goals conceded by B = expected goal difference.

perhaps multiply the two but use probabilities?

[JRT]

Ok Guys

Maybe I was a bit brief in my explanation.

First off the solver is an add-in tool, which can be used to "solve" things

Basically my model uses past games to calculate the Off and Def ratings. Its a least squares model.

After a few matches have been played you can start to calculate the ratings. Team A Off - Team B Def = Team A Expected Average score. We then take the noise(error) which is calculated by Actual Score - Expected Score. Then I square this number. I total all the squares and use the Solver to reduce this number by finding the optimal values for each teams ratings.

I have more variables added in for weighting etc. but still I produce defensive ratings which are higher than some teams offensive ratings, which gives negatives which cant be computed into a distribution.

Do you follow now?

JRT

[plez]

When you say it's a least squares model, are you using linear regression? If so, what are your dependent and independent variables?

[JRT]

Plez

Maybe that is where I am going wrong, am quite new to this sort of thing, and have no idea what you are talking about

Someone gave me a simple sample sheet, which looked at the NBA, now I want to try to develop it for the soccer.

Do you know of any good links to read up some more on this?

I fear I am peeing in the wind, without the full knowledge of how thins work.

JRT

[plez]

Joe Buchdahl's book on fixed odds sports betting is popular on this forum. It shows you how to use simple stats that are available in Excel, as well as a lot of good background info and advice on staking plans etc. More information is on his website - a partner site to PL, with a link at the bottom (sorry, don't know how to post links!). Alternatively keep your questions coming in this thread if you want, I'd be quite happy to help out

[JRT]

Plez

If you IM me your e-mail I would be happy to e-mail you a sample sheet, for you to look at the method I am using. It will only be a small simple sheet to out line the details of the methodology.

Unfortunately for now I am working in internet cafes and have no access to the add in tools for Excell, just want to try and get my knowledge up to scratch, before tackling it head on.

I have some interesting(well I think) ideas of how to use the sheets, just need to iron out my initial problems.

Regards to Joe's Book, again as I am in Thailand right now, without CC's I cant purchase the book. It will be the first I buy when I return to Europe, which is hopefully soon, just trying to get a job to go back to. Working here just isnt giving me enough money!

Thanks
JRT

[Joe]

Can you do bank transfer with Moneybookers.com, JRT? If you can, I'll send you a copy. Let's call it a tenner (or 15 Euro if you prefer that currency).

E-mail me if you're interested:

joseph"at"football-data.co.uk

Replace "at" with @

(I don't like to have my e-mail address on show in case of spam harvesters picking it up.)