Compiling your own Football ratings help.

sorry scenario b is 45% 20% and 35%

You would need a lot more than 10 games and 5 games respectively,
in fact you would need about 30 results for each side. Historical
results also have to be considered, which includes previous seasons
for some clubs. For example last season Liverpool were always rated
clearly better than Newcastle despite the fact that the latter side
was constantly out performing the former. That would just the tip
of the iceberg. GL.

kenilworth-For example last season Liverpool were always rated
clearly better than Newcastle despite the fact that the latter side
was constantly out performing the former.

so true wonder if the markets will change this season probably not

Very simplistic approach but here goes:
E.G.
Home Team Won 7 Drawn 2 Lost 1
Away Team  Won 3 Drawn 1 Lost 1

Assume wins and losses are by 1.5 goals on average, and the numbers are the last 10 of the home team at home, and the last 5 of the away team away.
And they play opposition of equal strengths ( yeah, right ).
Home team on average wins by 0.9, away team wins on average by 0.6
So expect the home team to win today's match by 0.3 of a goal - which makes them 2.34 chances, draw 3.55, away 3.4 using widely available tables for converting supremacy into probability of the 3 different outcomes.
You then have to finesse the probabilities to allow for whether it's going to be a high or low scoring game ( low scoring increases the draw likelihood a little ) and what both teams are trying to achieve from the match.

Sorry Bongo, could you explain that again for me please, with a little further explanation?

For ease of use I will use similar games played and assume games are against similar opposition

Home Team  W3 D1 L1   F 7   A 3
Away Team  W2 D2 L1   F 6   A 4

Also can you point me in the direction of where I can find the tables for converting supremacy into probability please.

Drat, I thought it was a goodish explanation already Squirrel:

For ease of use I will use similar games played and assume games are against similar opposition
Home Team  W3 D1 L1   F 7   A 3
Away Team  W2 D2 L1   F 6   A 4
Anyway, the Home Team here has a goal difference of +4 over their last 5 home matches ( average +0.8 ).
The Away Team has a goal difference of + 2 over their last 5 away matches ( average +0.4 ).
Both clearly useful sides - but for today's game the expected supremacy is the difference between the ratings which is 0.4 making the odds approximately 2.16, 3.65, 3.8.
These odds would need major finessing as these are 2 low scoring teams ( 2 goals per match on average, compared to the average 2.73 across the major english leagues and cups last year ).

Here's a real example using 2011/12 league results only:
Saurday 18th August:
Arsenal versus Sunderland
Home Team: W12 D4 L3 Goal Diff: +22 Avge 1.16
Away Team: W4 D5 L10 Goal Diff: -10 Avge -0.50
Supremacy for Arsenal on opening weekend then is 1.66 ( 1.16 --0.5 ), which makes Arsenal approximate 1.33 chances.
As always that probability needs finessing to take into account expected number of goals ( about average for this game - although a lot of people think Arsenal are a high scoring home team ), European distractions, progression in the 2nd half of the season, results in other competitions - it's really only a starting point.

As for the tables - 'The Definitive Guide to Betting on Football' by Kevin Pullein has them. You could infer them yourself from bookies who provide both fixed odds and supremacy markets on the same match. I didn't say it was free or easy.

Oops, arithmetic fail on Sunderland there. -10 divided by 19 is -0.53 of course. doh

Cheers Bongo, the explanation was good enough for most people but I was always the slowest one in class.

I have got that now, thanks for your time and effort. I have that book somewhere at home so will dig it out.

I was after something that gave me a good starting point to base my assumptions on and that has helped massively, thank you

There is an approximate formula for converting home supremacy ( s ) into a % likelihood of a home win:

100*(0.363+(s*0.237))

It's very rough, and doesn't give good estimates at extremes ( s greater than 1.9 ) but it's not bad. Using tables is better though.

Hi Bongo, which page are the tables on that I need to look at?

That I don't know Squirrel Junior:
I'll look it up in the bookshop in the city later this week. Don't own a copy but I'm assuming from the amazon reviews and the title being 'The Definitive Guide to Betting on Football' that they have to be included or else it's not definitive and Mr Pullein needs pulling in by his whiskers for a chat with Trades Descriptions.

Thanks Bongo most appreciated.

try the following link and page 6 is this the table I need?

http://www.football-data.co. uk/ratings.pdf

This is all I have been able to find despite searching extensively on Google. The data seems quite old, will it still be relevant today?

Just been looking at that table Squirrel, and it's actually pretty good - what I previously got as a 1.91 chance ( from self-derived data from the last 6000 matches in the top 5 Eng divisions ), it gets as a 1.89 chance for example, which is a negligible difference ( and there's no way of telling which is right anyway, as far too much data would be needed ). The table, and the regression formulae break down when the superiority goes above around 1.9 ( or 22 using their 12 match rating method ) but there's very few matches between teams that far apart in ability to be bothering with them.
Overall, it's excellent. A good find and free! ( and I wasn't previously aware of it ).

Have a look for ELO and Sagarain, the latter with regard to college football in america, the former with regard to games with no home advantage, but also chess, where white could be considered home advantage.

When you look at the home and away teams' goal supremacy, do you include both their home and away from in the average you calculate, or for example do you just look at the home supremacy for the home team, and the away supremacy for the away team?

I'd say the latter is a better approach, as a team's form can fluctuate considerably depending on whether they are home or away.

Home advantage is massively key in football betting. Plenty of academic papers on it although none are definitive.

Anyone analysing just home form versus away form for a match-up is ignoring half of the available information about how good the teams are and will be on the fast way to the poorhouse ( or to a HB claim as we're in the 21st century ).

Which might be a good thing if that other 50% gives you misleading information, or information that is not wholly relevent to the game under analysis.

Home advantage is not a secret and is factored into all betting.
IMO Bongo is correct in his post.

Bongo is spot on

Home/Away form is meaningless really, unless there is some special factor (eg plastic pitch) making it significant.

Teams should be rated/priced up on their overall abilty, not just how they have played in previous Home matches only, or previous Away matches only, with home advantage factored in after you've done that.

I prefer to look at the home form of the home team (relative to the home form for the league as a whole), and compare this to the away form of the away team (relative to the away form for the league as a whole).

Doing that is very misleading a lot of the time as 'good home teams' may just have played most of the strong teams in the league Away at the time you are looking at it.

One season , about 2004/05 ,Charlton were talked up as being a particulary good away team, but it was simply that they had played Arsenal,United,Chelsea and Liverpool at home before Xmas

You do get discrepancies over a few months with a team having, say, the 3rd best home record but ranked 13th on Away points. But these just aren't sustained long term.

In the long term the 5th best team overall will have the 4th-6th best Home Record usually and the 4th-6th best Away Record.

joci, when you discover a side, say 'over-achieve' at home,
away etc, do you find they continue to 'over-achieve' ?

How would you factor in Home advantage?

For example Man U at home to the bottom 5 teams in the last 2 seasons

Home win 90% of the time and Away only win 70%

Wigan Home to Top 4 last 2 seasons

Home lose 75% away lose 88%.

There is quite a big gap between Home and away so how much would you factor in? and how would you go about factoring home advantage?

Or if you used goal supremacy how many goals extra is home advantage worth?

Someone will jump in here with a sweeping statement along the lines of "home advantage is worth about 0.4 of goal" as if it is a constant. And they will probably believe it is constant.

in the long term they would be right

No discussion on football odds' compilation can begin without a thorough study of the statistical distribution compound bivariate discussion.

Plenty of academic papers available if you're willing to do the work.

In addition, the spread firms even do all the stats for you, by helpfully providing quote about total goal expectation & Home vs. Away goal supremecy.

Some people can't get enough of looking at matches involving the Big Name Premier League Contender at home to the doomed Championship side spending their barnsley year in the big-time.
The truth is matches with this ability gap are fairly few and far between. Maybe 10 a season - the top 2 at home to the bottom 5. It's really not worth the effort and there's little data. The lowly team might give up trying if they go behind and save it for a Wigan the following week, the higher team could be saving a couple of good players for a Milan or Bilbao in mid-week.
Matches like Fulham versus Norwich are what you want to study - you know both teams will likely fancy themselves equally and give it a crack.
Take the last 30+ games as kenilworth i think said regardless of home or away - they were all games of football involving skill, effort and under the same rules and tell you more about their relative merits than using 15 of the last 30. Then finesse the odds according to other factors you think are important.
You wouldn't start the other way about and use the last 15 home matches, then finesse from there using the other 15 that you've so far ignored. That's surely an approach for the fanciful.

What I've found curious from my own studies is that home advantage was an average 0.30 across the top 5 English divisions last season but as silverback implies that is an illusory constant. The constant is that home advantage is around 11% of the goals expected but expressing it that way is clumsy but will try to explain - 2.73 is the average goals per game ( 11% of this is 0.3 ), but expected goals increases with ability difference and attacking styles. A match with expected goals of say 3.2 would attract a home advantage of 0.35, while one with expected goals of 2.3 say would have a home advantage of 0.25. These are extremes though, and best avoided just as the Manchesters at home to the basement teams should be.

Blogger: steeringjobnap's blog
No discussion on football odds' compilation can begin without a thorough study of the statistical distribution compound bivariate discussion.

Plenty of academic papers available if you're willing to do the work.

In addition, the spread firms even do all the stats for you, by helpfully providing quote about total goal expectation & Home vs. Away goal supremecy.

Very helpful, and usually very accurate.