Figgis
Kincsem
Personally I'd say that betting stats from as much as 70+ years ago have no relevance to today anyway.
Added to that, I don't see how because an odds on fav got beat in the race 15 years ago it would have any bearing on this year's result any more than would the fact an odds on favourite won 6 years ago.

I took on the laborious task of inputting the full fields from 1920-2014 into a database, 1500+ runners, and as much info as I could glean from the results.
The reason I did it is to get an idea why an odds-on favourite from "15 years ago"  got beat.  I am trying to learn lessons from the past and apply them to the present.
And if I am alive next year I will still have the data.

So why would the past have any bearing on this year?
An example would be the effect of the draw.  It appears a low draw is best, and there are qualifiers to that statement .

One result intrigued me that appeared to contradict the draw advantage.
1983:  All Along won from stall 24 in a field of 26 runners.  That blew my draw-bias theory out of the water.  How did she do it?
A few things explained how she did the impossible.
All Along was taken over to the stand rail from her out draw of twenty-four.
Sailor's Dance set a blistering pace up front.
About 300 metres out Seymour Hicks veered away from the rails, a gap opened for All Along.
Walter Swinburn seized this opportunity.

Other interesting facts from the 1983 Arc.
Not one of the colts that finished in the first three of the French, English, or Irish Derbys was in the Arc field.
This might explain why the first four Arc finishers were fillies, and 7 of the first ten were female.

Past results that I like to investigate:  Rainbow Quest 18th, Rainbow Quest 1st.

Knowing the past and interpreting the results help in assessing the present (my opinion).

My own worries about the draw,  is that if you have want to be close too the pace from a wide draw, the chance of interference would significantly increase,  if trying to get across too the rails, the french stewards can be servere.

Knowing the past and interpreting the results help in assessing the present

I totally agree, which is why bare statistics of odds on favourites having had a less than expected winning ratio is of no use without some kind of analysis of the bigger picture.

Of the more recent failures (which at 20+ years ago isn't all that recent), such as Generous and Reference Point, those horses just didn't run their race at all and I have already put forward why it wasn't totally unexpected. I think punters today are a bit more enlightened about horses having hard seasons, but if Treve was a non runner and Golden Horn became an odds on favourite would anybody really be shocked if he still finished unplaced? I know I wouldn't.

Those circumstances don't apply to Treve. If she doesn't run her race then the only reason that's been put forward why she might not is that she was so impressive last time and it might have taken a lot out of her. Which is possible but in view of the slow time of the race doesn't seem that strong a possibility.

Karpino is a very interesting runner if turning up, German 2000 Guineas video here: - https://youtu.be/dQl9iRNBmrs

Now Karpino is a Cape Cross out of a Sadlers Wells mare, the dam did not stay for me, he has shown excellent speed and that must be a worry or a blessing? but the fact is that his for can be percieved on a similar level to Gleneagles and interesting that trainer as  been so patient, perhaps injury problems? not sure what the true story is.German runners generally do go unoticed, but I just wonder what you lot make of this one? is this a superstar?

most of those in the German  2000 guineas appear to be sprinting sorts and  the  form line I have taken is  Cappella Sansevero beaten 9.25Lenghts by Gleneagles and 11.25 lenghts by Karpino, incidents in both races moreso for me against Gleneagles.

Meant he and him obviously regarding Golden Horn. Also, if the ground is too soft at Ascot in the Champion Stakes then I think he would be saved for the Breeders Cup - a mile and on a half on a tight road like track would be right up his street. Whatever is said, my prediction is Jack Hobbs runs in the Arc and Golden Horn will run in the Champion Stakes, if it's too soft then he will be saved for the Breeders Cup, an event which The Gos likes to target.

I am going out for the afternoon in about 20 minutes.
What I would like to know is the quality of horses Treve beat in 2013, 2014, 2015 before the Arc i.e. how many group winners.
I might do that this evening.  Is Treve's impressive 2015 form really impressive?

My doubt about her is
(1) 2013 impressive on soft from bad draw, but getting the weight allowance.
(2) 2014 impressive, but drawn 3 which imo gave her an advantage on good ground, beating Flintshire drawn 4.
(time 4.45 fast might mean it was not good but was firm.  Most of the times that day were fast, the slowest about standard.  The draw advantage is increased the firmer the ground).
Perhaps her task was made easier by the jockey of Gold Ship (JPN) drawn 2 last year idiotically taking his horse to the back of the field ffs then trying to do the Japanese jockey showboating thing of coming around the field to win (and of course at Longchamp not winning).

Thanks kincem. Apologies if you posted this earlier.

Considering that the Arc is a stakes race i.e not a handicap, 13 long-priced winners out of 93 races plus the proportion of short prices beaten,which you listed earlier, rather supports my impression that the race is trappy.

Of the recent outsider winners,(since 69)  Solemnia, Urban Sea, Star Appeal won on soft or heavy . Gold River's year was given as "dead.".Levmoss, Trempolino, won on g/f or firm. The other 2 were on good. So the ground factor doesn't prove that the shocks were just down to soft/heavy ground alone.

Incidently, the average price calculation looks suspect. Did you add price percentages or actual  prices? If prices, that would be misleading.

Madhu

I don't know the anser to the question which you posed kincem, but I do know that I have always over the years considered that the perfect profile for an Arc winner is the speed to win at 10f or less at group level as a a 3 yr old and proven stamina at 12f at G1 level.

Rail Link was 8/1 so not really a shock. I think most of us would concede we underrated Danedream, or in my case just didn't have a clue about her. So took the view that if she is good enough it will just have to be taken on the chin, as more often than not that kind of foreign form doesn't live up to its promise. Trempolino won when Reference Point disappointed, Mtoto was coming back after an enforced absence and nothing else was really strongly fancied. Other big priced winners can be explained by weakish fields and bad ground.

We could get a race where Treve disappoints and, as has already been mentioned, it wouldn't be too big of a shock if Golden Horn has had enough for the season, so yes given that scenario it would be no surprise to see a big priced winner. It just depends on what chance you think there is of that scenario happening compared to the prices on offer.

Sandown- would I be right in the last 10 winners all had previously won over 12f?

Think so Madhu but Bago in 2004 hadn't won at 12f although placed close up in the Niel. Fortunately, I kept the faith.

thing is with Found - she has not had the opportunity to race at 12f yet. So, comparing like with like, she's almost unique. Antepost favourite for Guineas and Oaks on back on Prix Marcel Boussac romp, being held up early in the year is probably the making of her in the Arc - all this previously stated ofc, but worth repeating for those who question her lack of a 12f win.

I just think you have to look at her as a unique case - her talent is undoubted, hands and heels romp over Ervedya, superb run in the Moyglare on her second start. Held up and still placed three times in Group1, now trained for the Autumn, skipped the Vermeille and was 2nd in the Irish Champion - absolutely no surprises if she wins this.

couple of furlongs but then they really got going - obv Ervedya didn't want to make it

so what was her finishing speed then !?

She didn't have to travel, and the Yorkshire Oaks would have been a step too far for her first run back because she did look like she needed that.

The trainer said afterwards she would likely go to the Vermeille, but they must have felt she was ready for a proper race.

I think she'll come on again, and though she handles soft ground she'll be better on good.

Sandown
Incidently, the average price calculation looks suspect. Did you add price percentages or actual  prices? If prices, that would be misleading.

Good spot.
I was using the previous year odds which I assume were Pari-Mutuel odds.

An example from the 1960 Arc might explain my approach.
17 runners, and when you input all the runners and odds you get an over-round of 268%.
But 2/5 Charlottesville, Sheshoon, Princillon (couple); 29/1 Dalama, Flores (couple).
Obviously they were not all 2/5.
It is usually obvious which of the coupled horses is the intended, and which are the pacemakers (from the result).
I fudged by going 2/5 Charlottesville (6th); 100/1 Sheshoon (9th); Princillon 100/1 (17th); and 28/1 Flores (8th); 100/1 Dalama (10th)
Giving the pacemakers in the coupled horses 100/1 probably reflected their chance.
This dropped the overround to 125% in 1960.

Each year I adjusted the odds and got a sensible overround of ~115% to ~128%.
You can see jumps in the overround, lower from 1920 to 1944 below 120, and after 1944 in the mid 120s.

Sandown
Considering that the Arc is a stakes race i.e not a handicap, 13 long-priced winners out of 93 races plus the proportion of short prices beaten,which you listed earlier, rather supports my impression that the race is trappy.
Of the recent outsider winners,(since 69)  Solemnia, Urban Sea, Star Appeal won on soft or heavy . Gold River's year was given as "dead.".Levmoss, Trempolino, won on g/f or firm. The other 2 were on good.
So the ground factor doesn't prove that the shocks were just down to soft/heavy ground alone.

It is trappy. 
People assume form on other courses can be transferred to Longchamp.
1) horses may have hard seasons
2) the Arc is in October (people forget this) and the ground is often soft
3) traffic problems as the race is almost always on the turn
4) typically the horses run in two abreast so it is each to be in group eight, about 12 lengths off the pace.
5) jockeys unfamiliar with the course (Japanese especially)
6) German and Italian runners treated by the betting public as if they have no place in the race

Look at Urban Sea's win in 1993 Arc at odds of 37/1.  Time 2:37.90 which is one of the slowest (there are many slower but that was in the good old days).
Hernando was the 3.7/1 favourite.  He finished 16th.  Ground heavy.  He was drawn 13 of 23.
The next year, 1994, Hernando finished 3nd beaten a short neck.  Time was 2:31.10 ground good/soft (an average Arc time).  He was drawn 10 of 20.
You might think a draw of 10/20 and 13/23 are the same, both about half way.  One horse has to get past 9, the other has to get past 12.

Before the 1993 race people probably thought Hernado went on soft as he had won on heavy and soft. 
But both of those wins were in five runner races (+15.60 and +6.20 to standard) and both featured Dernier Empereur whose going preference remains a mystery to me.
Hernando's results before the race included 1st of 5 good; 1st of 11 Gd/fm; 2nd of 12 Gd/fm (Irish Derby).  imo he was a good to good/firm horse.

I think it pays to look very, very carefully at the going preference of horses, especially if the going is firm or the going is soft.
For example, look at Vert Armande:....[Arc 1992; 2:39.00 drawn 12, 3rd].....[Arc 1993; 2:37.90, drawn 10, 9th].....[Arc 1994; 2:31.10 drawn 11; 19th]
It is obvious the draw made little difference to Vert Armande, but he really needed soft ground.

How about the 1981 Arc, won by Gold River at 53/1
The horse was trained by Alec head.
Ten days prior to the race Freddie head obtained permission from his retainer , Monsieur Jacques Werthwimer, to Ride Detroit instead of the owner's Gold River.
Wasn't that amazing?  The jockey asked his retainer Wertheimer is he could get off  Wertheimer's Gold River, and Ride Robert Sangster's Detroit 7/2 2nd favourite.  Detroit had won the Arc the previous year.
That might have been part of the reason why Gold River's odds were 53/1.  Gold River's trainer, Alec head, was not very happy with his son's decision to get off his horse.
Detroit had won in 1990 in 2:28.00 (given as good/soft but imo much faster).
The 1981 ground was also given as good/soft but Gold River's winning time was 2:35.20, 7.20 seconds slower than the previous year.
Gold River was stepping down in distance from her previous group wins: Prix De Pomone (Gr3) 2700m; Prix Royal-Oak (Gr1) 3100m.  Plenty of stamina.

The amazing 119/1 odds of the 1975 Arc winner, German horse Star Appeal confuse me.
Would the French not back a German horse?
He was 3rd in the Benson & Hedges Gold Cup 10.5f btn 6.5l by Dahlia, before that 9th in the King George VI & Queen Elizabeth II 12f (the great high pace Grundy/Bustino duel).
In 1975 (his Arc win year) Star Appeal won the Eclipse Stakes (Gr1) 10f and the prestigious Gran Premio Di Milano (Gr1) 2400m
Amazing:  a double Group 1 winner earlier in the year, and one of tose wins at the Arc distance started at 119/1.

When you did deeper there is often a story as to why favourites are favoured and outsiders are ignored.

Best to ignore what the racecourse going description and form your own opinion.
Another dodgy thing imo was early times.  From 1920 to 1931 time given ended in .80 ten times e.g. 154.80; 158.80; 160.80; 153.80 (obv 1/5 sec clocking)

oops, so many errors in my posts above.
Predictive text, pudgy fingers, and addled brain not helping.

Figgis
Rail Link was 8/1 so not really a shock.

It was a shock to me when I saw 8/1.  Where did I get 23.6/1?  From Timeform's Racehorses of 2006.
I used Pari-Mutuel prices (probably closer to Betfair wild swings) to stay consistent.
Deep Impact was a tasty 1/2 fav. 
Someone told me he had the biggest bet of him life on Deep Impact.

I agree that the race is often trappy. I've said the same thing in previous years which is why, even though I really enjoy the event, I've also said it's not one of my favourite races in the calendar for a big punt, apart from the odd year when you get a fresh runner going into the race with form good enough. That's because I'm a punter who usually backs one horse in a race or occasionally will back two. If I were a punter that made a book around the race, backing half a dozen runners and trading, as others do, then it would be different as it's usually a race that you can at least narrow down in most years.

The big difference this year is nearly all the explanations of why it's a trappy race do not apply to Treve. About the only one that does is she may get trouble in running, as any horse in the race may. However, it's difficult to think of any in past years that I thought would definitely have won the race only for trouble in running so I'm not sure it's a concern here any more than it would be for any big sized field (and this year could possibly have fewer runners than usual).

I'm all for looking for weaknesses in a short priced favourite and Treve is by no means a cert, but anyone still arguing that she should be bigger than evens seems to be clutching at straws in my view and is probably being influenced by taking a stand against her earlier.