Favorite/Longshot Bias alive and well

[highnote]

This is an excellent example of how favorites are underbet and longshots are overbet.

From Steven Crist of Daily Racing Form:

The betting public got it right by a whisker, dispatching Street Sense at 4.90-1 over Curlin at 5.00-1. An $11.80 win mutuel on a favorite was the highest in Derby history and as high a price on a post-time favorite as you will find in 10,000 American races. This is largely a function of having 20 separate betting interests instead of the usual limit of 14, but also reflects that Derby Day bettors, bless them, would not let a donkey go off at more than 60-1. No one in the Derby field was higher than 58-1, and one race earlier in the Woodford Reserve Turf Classic, Shake the Bank - a horse on whom parimutuel wagers should not even be permitted since his sole function is to set the pace for stablemate Better Talk Now and get out of the way - went off at only 41-1.

[Edward DeVere]

That's funny - I was JUST thinking the same thing. Because of Giacomo, favorites in the Derby may be underbet for the next several years.

[cnollfan]

I have been contemplating this same thing. Storm In May is a good example. He was 30-1 in the Arkansas Derby, in which Curlin was 4-5, and got beat by 10 lengths. Curlin, despite winning by 10 lengths, went up from 4-5 in Arkansas to 5-1 in Kentucky because the field was so much deeper. Not only would Storm In May have to improve 10 lengths from his Arkansas Derby form to turn the tables on Curlin, but he also would have to beat the winners of the Florida, Illinois, Louisiana and Santa Anita Derbies, as well as the winners of the Lane's End, Wood Memorial and Blue Grass, none of which were in the Arkansas Derby. Yet the crowd gave Storm in May an even better chance to win in Kentucky than in Arkansas.

Tiago was also suspiciously low (14-1 in Kentucky vs. 29-1 in the Santa Anita Derby, a race so thin that allowance winner Sam P was the 2-1 favorite). Although I thought Tiago was a very poor value in Kentucky at least I understand how some bettors could think otherwise. All I can come up with on Storm in May is that he had an appropriate name for the conditions.

If they ran the Derby on a Thursday afternoon at Aqueduct I don't think the crowd would come to the same conclusions as it did last Saturday.

[RXB]

One example does not mean anything.

Favourites nowadays, as a group, are underbet only minimally; it's not like it was 30 years ago. If you spend your days betting a lot of 25/1+ shots you'll probably get clobbered, but except for those big longshots, the overall return is pretty even right across the odds levels.

[JustRalph]

I couldn't believe Shake the Bank wasn't 90-1.........I guess a bunch of people that never follow racing were throwing money in the pools all day long

[highnote]

One example does not mean anything.

I disagree. It means something, otherwise I wouldn't have posted it.

It means that in this year's KY Derby there was a huge favorite/longshot bias.

I should have been clearer in my original post that I was only referring to the Derby.

However, in many major U.S. races you'll still see a fav/ls bias --especially when there is a lot of amatuer money in the pool. Think back to the Rick's Natural Star in the 1996 Breeders' Cup Turf Classic won by Pilsudski.

http://www.accessmylibrary.com/comsite5/bin/pdinventory.pl?pdlanding=1&referid=2930&purchase_type=ITM&item_id=0286-5535146

Rick's Natural Star was an old broken down claimer that was eligible to run in the Turf Classic. He had no business being in a race with some of the best 12 furlong Turf horses in the world. I don't think that Rick's Natural Star had ever even raced on the grass in his whole career! The owner was only able to enter him in the race because there was some kind of loophole in the rules that made him eligible. The horse hadn't had a race in such a long time that the owner trained him as he shipped him in-route to Toronto, Canada from the Southwest (Arizona or N. Mexico). He would hold Rick's Natural Star and let him gallop alongside his pickup truck as he drove.

Do you want to guess what Rick's Natural Star's odds were? I'll tell you. 56-1. That is a longshot bias, my friend. Literally, just about the only way Rick could have won the race is if every horse except him would have fallen down. What were the odds of that event occuring -- at least 100,000 to one -- and it was probably more like a million to one. Maybe even higher.



Favourites nowadays, as a group, are underbet only minimally; it's not like it was 30 years ago. If you spend your days betting a lot of 25/1+ shots you'll probably get clobbered, but except for those big longshots, the overall return is pretty even right across the odds levels.


I agree. Over the course of the year in America (and probably other major racing jurisdictions) the fav/ls bias has largely disappeared. A small longshot bias still seems to exist in N. America.

The bias may still exist at certain tracks and at certain times of the year. My guess is that at Del Mar and Saratoga there is a bigger bias than say the Aqueduct Inner Track meeting.

[BlueShoe]

Do not quite agree with Crist in the DRF about 9-2 favs being the longest priced.A number of years ago,at I believe,Hollypark in a 12 horse field,bottom level claiming for older fillies and mares,the favorite went off at 6-1.Actually,there were tri favs;the actual favorite was 6:00-1,the second choice was perhaps 6:20-1,and so on.Details are fuzzy,that race was years ago,but think that about 6 or 7 of the runners were clustered around 6,7,or 8 to 1.The odds were so unusual that I made a point to study the chart of the race.Darned if I can recall the price of the winner,just too long ago.

[highnote]

I looked up Holly Park and couldn't find a race where she won at greater than 3-1.

Maybe the races I have for her don't go back far enough.

[Froggy]

I remember the race that BlueShoe is referring to. I don't recollect which track it was at but am reasonably sure that it was in southern California and I bet two horses to win and place and a 3 horse quenelle box and they came in 1st and 2nd.

Froggy

[boomman]

swetyejohn wrote:Rick's Natural Star was an old broken down claimer that was eligible to run in the Turf Classic. He had no business being in a race with some of the best 12 furlong Turf horses in the world. I don't think that Rick's Natural Star had ever even raced on the grass in his whole career! The owner was only able to enter him in the race because there was some kind of loophole in the rules that made him eligible. The horse hadn't had a race in such a long time that the owner trained him as he shipped him in-route to Toronto, Canada from the Southwest (Arizona or N. Mexico). He would hold Rick's Natural Star and let him gallop alongside his pickup truck as he drove.

Do you want to guess what Rick's Natural Star's odds were? I'll tell you. 56-1. That is a longshot bias, my friend. Literally, just about the only way Rick could have won the race is if every horse except him would have fallen down. What were the odds of that event occuring -- at least 100,000 to one -- and it was probably more like a million to one. Maybe even higher.


swetye: To add a bit more detail to this story, I was announcing in New Mexico when this fiasco came about and it was a vet from New Mexico, (I believe his name was Livingston) and Rick's Natural Star was even an underlay against the morning line on him which was 99x1. He bled and didn't even make it around the course that day (Woodbine I believe was the host of that particular Breeders Cup) and believe it or not, was claimed a short time later at Los Alamitos for $7500. People proved without a shadow of a doubt that they WILL bet a name or a story (re: Storm in May getting bet down in The Derby this year) The true odds on Rick's Natural Star that day?
EASILY A MILLION TO ONE!!!!!LOL:D

Boomer

[bobphilo]

I couldn't believe Shake the Bank wasn't 90-1.........I guess a bunch of people that never follow racing were throwing money in the pools all day long

One would have to be really out of it to bet Shake the Bank. The funny thing is he almost beat Better Talk Now who just caught him in the last strides.
Of course BTN didn't run his best race, but it makes you wonder how Shake would have done if he had been rated a bit early and not played the rabbit?

Bob

[GMB@BP]

That's funny - I was JUST thinking the same thing. Because of Giacomo, favorites in the Derby may be underbet for the next several years.

this is nothing new, has been happening the past 5 races since his win.....and people hate Giacomo.