Tuesday, May 03, 2022

Decimal odds and heavy favorites

Continuing this series on sports betting and decimal odds. The topic of this post is when one team is a big favorite to win a game. Is it possible to take enough small wins and avoid the big losses to grind out a profit on big favorites.

Betting on heavy favorites, the better team in a game that looks like a mismatch. It's a bit like picking up pennies in front of a steamroller. You can win a small amount or lose a large amount. Seems like easy money until it isn't.

A game that looks like a mismatch might not be a lock though. some examples
Undertaker vs. Brock Lesnar, WrestleMania XXX, 2014
Mike Tyson vs. Buster Douglas, 1990
UNLV vs. Duke, NCAA Basketball Final Four, 1991
wish I had the link. A guy lost $17,000 on women's tennis laying 170:1 when an unranked beat a top player. The big name player had to pull out of the match with injury.

For this post, I will define heavy favorite as having decimal odds in the 1.05 to 1.10 range. On ALC anyway 1.05 is the floor payout on favorites. A bit more on that below. From my earlier post, I calculated at 1.05 the break even point is 95.24%  At 1.10 the break even is 90.91%

So even though these bets usually win, the player is laying heavy odds. A loss is unusually bad as each loss will take numerous consecutive wins just to cover it and get back to even. Still I wonder if there may be opportunity to find long-term profitable plays among heavy favorites. To grind a slow, steady profit and minimize disastrous upsets.

quantifying the strength of a favorite

One thing I noticed on ALC Pro-Line is that for a given favorite odds such as say 1.06, on different games the odds offered on the underdog can vary. From my earlier post I noted that house underdog prices serve two purposes. To reflect the probability that the underdog will pull an upset; and to draw bets on the underdog, to balance against heavy action on the favorite.

some recent examples from Pro-Line

NBA playoff series

Atlanta 7.25
Miami 1.05

Toronto 6.75
Philadelphia 1.07

Boxing

Dillian Whyte 4.70
Tyson Fury 1.10

So if we take a bit of a leap. use the underdog decimal odds as a kind of proxy, an estimate that the underdog will win. The lower the underdog probability, the safer the play on the favorite becomes. so a higher underdog number means a lower probability that the underdog will win. This can provide an extra piece of data when evaluating betting on a favorite. At different prices, 1.05, 1.06, 1.07, 1.10, with some data research there may be a floor underdog price that can make that play on the favorite good. when combined with other research on the game.

Now comparing various favorite options. As the price on the favorite increases from 1.05, the underdog price will go down. Of course as favorite prices increase, the winning payout increases, which can allows more risk or tolerance for upsets. For example 1.07 pays 40% higher than 1.05. 1.10 pays out double on 1.05.

I got thinking about how to compare or somehow quantify the favorite and underdog prices. I came up with a "strength of favorite" number. with favorites, we want to optimize the small winning payout against how often we have to eat a big loss.

Let Pf be the decimal odds on the favorite.
Let Pd be the decimal odds on the underdog.

then the strength of favorite number is defined as
(Pf - 1) * (Pd - 1) * 100

the examples above come out as

Game Favorite Decimal Odds (Pf)
Underdog Decimal Odds (Pd) Strength of favorite number
Miami vs Atlanta NBA Playoffs 1.05 7.25 31.25
76ers vs Toronto NBA Playoffs 1.07 6.75 40.25
Tyson Fury vs Dillian Whyte Boxing 1.10 4.70 37

 from there maybe 76ers at 1.07 might be the most promising of these three plays, as a starting point in research, in addition to other analysis on this play.

about 1.05

I noticed that 1.05 is the minimum favorite line that ALC will run. It is likely that at least some of these 1.05 are actually 1.02 or 1.03 "rounded up" to 1.05. So probably some of the 1.05 are mispriced for that reason. So if you can figure out where to look there may be an opportunity there. Still with 1.05, the break even point is 95.24%  which doesn't leave much room to work with to grind out a small profit. In some gross mismatches which can occur in international women's hockey and men's international soccer, ALC won't run a gift 1.05 moneyline. You have to lay a large points spread to play on the favorite.

in leagues that have achieved a lot of parity such as the NFL, NHL, and major league baseball, you don't see 1.05 lines. on any given Sunday is real and in general no single game is such a mismatch that the underdog has "no hope" and it's a minimum 1.05 play on the favorite.

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Update: on the featured matches above

Miami won the playoff series over Atlanta 4-1

Philadelphia won the playoff series over Toronto 4-2

Fury wins over Whyte in a six round TKO

 

so this time all of the favorites held. those who played on the favorites came out ahead