I uploaded some more data today to my website and if you run just favourites (both bet and lay side) you get the following:

There were 49527 horse form lines in the database at this point in time. We update when we get time.
There were 5147 selections for the System
There were 1757 Winners for the System for a strike rate of 34.14%
There were $5165.57 returned for WIN (after 5% commission) which means a Profit or loss of $18.57 or a percentage profit/loss of 0.36%

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The Rules used were : priceRank < 90 and priceRank = 1 and priceLayRank < 90 and priceLayRank = 1

That is showing a 0.36% profit after 5% commission just betting favourites with no filters. Figures taken from 10 secs before scheduled race time and market must be 95%. AUS Markets only.

I'd say that 34% is above the long term average though. Isn't it 33% or even 30% in Oz?

Yes it probably is a bit higher then long term average.
The results are since 8th August 2011 so its only 5 months of data. Still not a bad result for 5 months and over 5000 races.

A number of small observations.

Laying those horses is -10.90% after commission.
This reinforces the fact that although it should be neutral, Betfair favours backers in almost all areas.
Layers are pushing it up a hill.
Backers are starting off with an advantage and are further advantaged by market rules.
Layers start off disadvantaged and are further disadvantaged by market rules.

The TAB average for favourites is 33%, I would guess that the 1% is not a fluctuation, but rather better "picking".
Sometimes you see the inverse of first and second favourite on Betfair compared with bookies and tote.
I also think in the case of equal favourites, Betfair users are more decisive.

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I agree with everything you said Chrome. Betfair is full of people thinking they are better off laying. This is pushing up the prices slightly so that backing can be profitable as the value is on the backing of the selection. I am more and more concentrating on backing betfair selections rather than laying.

7 years of consistent profits, 2 losing days in December, and none so far this year........I'm happy to keep laying.

I ran a favourites analysis on Bet Selector and the NSW Tab favourite won 31.8% of races going back to the start of 2008. However it could be that in cases where the first 2 favourites are very close they could be mirrored on Betfair compared to the tote but you would need to go back the same amount of time to have a accurate figure on that.

I'm going to add to my past post.
The above is a generalisation, and that generalisation is true most of the time and for most of the field.
However, of late, I have been laying solidly supported runners at and below bookmaker SP!
I first noticed a trend a while ago and did some experimentation.
It seems backers and layers are obsessed with fixed odds displayed when it comes to heavily backed horses.
There is enough meat on the bone at bookie SP to make an earn, anything below that is is raw profit.
Fixed odds are constantly fluctuating as bookies automatically try to cover themselves by website algorithm.
There is a distinct advantage to this automation.
In the flurry to get on to what looks like a predictable further plunge in odds, Betfairians are chasing the fixed odds, but appear to be oblivious to the actual track SP.
For this approach, forget Betfair SP, as the opportunity passes us by, we miss the very large fluctuations and corrections.

Here are some some examples from yesterday:

Coffs Harbour R3 Mr Giggles SP $4.40 Fixed $3.80
Coffs Harbour R6 Little Johnie SP $4.00 Fixed $3.50
Kyneton R2 Tsar Of Russia SP $3.20 Fixed $3.10 (WON)
Kyneton R4 Victoria Bluebird SP $4.20 Fixed $4.00
Kyneton R5 Amber Grey SP $3.90 Fixed $3.60
Kyneton R6 Friend Indeed SP $5.00 Fixed $4.80
Kyneton R6 Bonny Jeunesse SP $6.50 Fixed $4.80
Kyneton R7 Tommy Two SP $5.50 Fixed $5.00
Kyneton R8 Sol Brillante SP $11.00 Fixed $9.50
Kyneton R8 Tough Love SP $5.50 Fixed $5.00

Only two meetings listed, only one horse of all those was a winner (the shortest price). Every horse traded at below SP in the last 5 minutes of betting on Betfair, some traded significantly below, and a couple well below fixed odds.

Instant bookie, without having to lay off, without laying above sp or getting caught out by late steamers.
In fact in most cases, after 5% commission ( I multiplied each price by 1.05), I was doing just as well as the bookies on track, but I can control my liability.

Happy New Year!!!

__________________
RaceCensus - powerful system testing software.
Now with over 426,000 Metropolitan, Provincial and Country races!
http://www.propun.com.au/horse_raci...ng_systems.html
*RaceCensus now updated to 31/10/2025
Video overview of RaceCensus here:
http://www.youtube.com/watch?v=W821YP_b0Pg

Thanks Chrome for sharing those valuable findings.

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Cheers.