Dolphin Power Rankings after Week 2

[MyGodWearsAHoodie]

Vegas has no idea what the betting public believes when it sets an opening line, as no bets have yet come in.  If it wants equal betting on both teams -- and it does want that, from the opening line on -- then its best bet is to set the opening line at the best predicted outcome of the game based on statistical modeling.  And that's what it does.  The last thing Vegas is going to do is leave itself vulnerable to a potential whale bettor (who likely also uses statistical modeling) to take advantage of an opening line that wasn't generated with sound statistical modeling.

At any rate, the upshot is that power ratings are used to determine opening Vegas lines.  They certainly aren't just "click bait" in that realm.

Some major glaring problem with this.  

First and foremost, the statistical models to determine the likely outcome has zero basis on the various power rankings published by different media outlets.  There may be some correlation because both are relying on the same underlying data sets, but the models don't use the power rankings.

Second, setting the line on a sporting event based solely on the most likely outcome wouldn't achieve the goal of the casinos to make money regardless of the outcome, because not all betters are gamblers, many are fans.  Let's say the Cowboys (largest fan base in the NFL) are playing the Jaguars (smallest fan base in the NFL).  There is going to be way more Cowboy fans betting on the game than Jaguars fans.  (There are probably folks on this site that ONLY bet on the Dolphins.) So the casino is going to set the line not based on the most likely outcome of the game, but rather a level that will encourage more Jaguars fans to bet, less Cowboy fans to bet, and gamblers to bet on Jax rather than Dallas that requires a line that is actually skewed to give Dallas worse odds and Jax better odds than the model would indicate.      

Finally, the purpose of publishing these lists is click bait.  That is why they are written.  They are not written to influence Vegas.  

 

[Dolfanalyst]

Some major glaring problem with this.  

First and foremost, the statistical models to determine the likely outcome has zero basis on the various power rankings published by different media outlets.  There may be some correlation because both are relying on the same underlying data sets, but the models don't use the power rankings.

Second, setting the line on a sporting event based solely on the most likely outcome wouldn't achieve the goal of the casinos to make money regardless of the outcome, because not all betters are gamblers, many are fans.  Let's say the Cowboys (largest fan base in the NFL) are playing the Jaguars (smallest fan base in the NFL).  There is going to be way more Cowboy fans betting on the game than Jaguars fans.  (There are probably folks on this site that ONLY bet on the Dolphins.) So the casino is going to set the line not based on the most likely outcome of the game, but rather a level that will encourage more Jaguars fans to bet, less Cowboy fans to bet, and gamblers to bet on Jax rather than Dallas that requires a line that is actually skewed to give Dallas worse odds and Jax better odds than the model would indicate.      

Finally, the purpose of publishing these lists is click bait.  That is why they are written.  They are not written to influence Vegas.  

 

This is what you said originally:

"Vegas lines don't give two shits about power ranks or even the relative strength of the teams...."

That isn't true, and that's all I'm addressing here.  Opening Vegas lines are based almost entirely on power ratings, and Vegas cares a great deal about the relative strength of teams in formulating opening lines, in fact using power ratings to distinguish teams from each other and generate the lines.

[Dolfanalyst]

Vegas has thousands of bets for predictions on the teams' ultimate finishes, as well as bets from the week prior showing trends.  If heavy bets were coming in every week on a sorry Cowboys team, Vegas would skew the opening lines towards the Cowboys, regardless of their actual strengths or what any Power Rankings say.

So you've illustrated well you know how closing lines are determined.  We're taking about opening lines, however.

False.  There was an opening line for BUF @ MIA (BUF -4, IIRC) on Monday morning before the Bills had even played, and Power Rankings are updated on Tuesdays.  They have nothing to do with each other.

Certainly they do.  You don't figure Buffalo's power ratings (the ones Vegas uses) were updated as a function of its game Monday night?

[Dolfanalyst]

This is pretty good rundown of how all this works BTW:

To determine what the odds should be on a given game, oddsmakers rely heavily on advanced mathematics, scientific formulas, computer algorithms and experience. They also take into account power ratings. A power rating is a statistical representation of how strong every team is compared to each other. It focuses on key statistical categories and considerations like margin of victory, strength of schedule and much more. By comparing each team's power ratings and crunching the numbers, oddsmakers will get a rough estimate of what the line should be.

Oddsmakers then adjust or tweak the line based on home field advantage, injuries, specific head-to-head matchups, scheduling and even weather. If a team suffers an injury to a star player or a team is playing their second game in consecutive nights, known as a back to back, that is factored into the odds. If a football team with a bad offensive line is facing a team with a great defensive line, that is also factored into the odds.

Once oddsmakers set the line, it is then released to the public. The initial line is called the opening line, or "opener" for short. Bettors can then pick which team they want to bet on. Generally speaking, the goal of the oddsmakers, also known as bookmakers, is to set a line that garners balanced 50/50 money on both sides. This way they can limit their risk and mitigate their liability.

Once a line is released, the limits are low. Limits are the amount of money the sportsbooks will accept on a given wager. The sportsbooks use this initial period when the line is first released as a “feeling out” period to see how the early market reacts. Sportsbooks want to protect themselves from professional bettors betting big amounts early and taking advantage of an incorrect or off line, known as a “soft “ line. The books allow professional bettors to bet on games at low limits to help them shape and mold the line to its strongest and most accurate number. Once a universal line is established, known as a "consensus line," then the market takes over.

https://www.vsin.com/sports-betting-101-sportsbooks-oddsmakers-and-setting-the-line/

[Spider-Dan]

So you've illustrated well you know how closing lines are determined.  We're taking about opening lines, however.

Certainly they do.  You don't figure Buffalo's power ratings (the ones Vegas uses) were updated as a function of its game Monday night?

How can the opening lines be "based on" Power Rankings that come out AFTER the opening lines have already been released?

The opening lines are the point spreads when then open, not when they are "updated."  After they are updated, they are no longer the opening lines.

I notice that after my original response, you now seem to be talking about "power ratings."  Is that the same thing as the "Power Rankings" released by various sports websites every Tuesday... the topic of this thread?

[Dolfanalyst]

How can the opening lines be "based on" Power Rankings that come out AFTER the opening lines have already been released?

The opening lines are the point spreads when then open, not when they are "updated."  After they are updated, they are no longer the opening lines.

I notice that after my original response, you now seem to be talking about "power ratings."  Is that the same thing as the "Power Rankings" released every Tuesday that are the subject of this thread?  Or is it some other system that no one was talking about?

The gist of the discussion is this:

Me:  Good power rankings are the stuff of which opening Vegans lines are made.  The rankings themselves aren't used, but the numerical values that place the teams in the order they're in certainly are.

MyGodWearsAHoodie:  Vegas lines don't give two shits about power ranks or even the relative strength of the teams, only about making sure equal money is flowing on both sides.


The point here, overall, is merely that Vegas uses statistical modeling in generating lines, just as some websites use it in generating their own power rankings.  Power ratings (or rankings) can therefore be tremendously informative, as you'd be hard-pressed to find a better determinant of the predicted outcome of games.

I use the term "ratings" and not "rankings" because as I said early on here, the rankings themselves aren't used by Vegas, but the numerical values that place teams in the order they're in certainly are.  The reason for that is that the distance between rankings isn't necessarily equivalent.  A ranking is therefore not necessarily a rating.

[Spider-Dan]

This thread is about the Power Rankings issued by websites like those in the OP.
If that's not what you're referring to with the Vegas opening lines, but rather the underlying team strengths and weaknesses on which those Power Rankings are based, then you're talking about a different subject.  Please take it to another thread.

[Dolfanalyst]

What we're talking about is what power rankings mean and how they can be used, Vegas's use of them being but one example.  This was one such response to the original post for example:

Quote from: Dave Gray on September 20, 2022, 03:48:51 pm
Maybe I should clarify.  I don't really know what power rankings are for.

Here's a great example:

https://www.espn.com/nfl/story/_/id/13539941/how-espn-nfl-football-power-index-was-developed-implemented

[Dolfanalyst]

This is a website the tracks the performance of various NFL power ratings:

https://www.thepredictiontracker.com/nflresults.php

Notice that for the 2021 NFL season the following system was best at predicting the outcomes of games against the spread:

https://rp-excel.com/

Power rankings can get quite sophisticated -- from the above site:

The rp-excel system uses genetic algorithms, neural networks, and monte carlo simulations to predict outcomes for various sporting events. With the use of these advanced technologies, rp-excel has been the only system, as documented by The Prediction Tracker, to show a positive ROI against the spread over the last 10 NFL seasons, predicting over 2,600 games.

[Dave Gray]

I started a new thread about Vegas odds, because I think it's a worthy subject --

In terms of the Dolphins, maybe I'm just too close to it, but I don't really see how the Power Rankings would have created the lines we see -- If we really are the 5th best team in the NFL, would we be getting nearly a TD at home?

I'm sure it plays into it, as power rankings seem to be a reflection of public perception.

[Dolfanalyst]

I started a new thread about Vegas odds, because I think it's a worthy subject --

In terms of the Dolphins, maybe I'm just too close to it, but I don't really see how the Power Rankings would have created the lines we see -- If we really are the 5th best team in the NFL, would we be getting nearly a TD at home?

I'm sure it plays into it, as power rankings seem to be a reflection of public perception.

That's again possibly a reflection of where the distances between power ranks aren't necessarily equivalent, and why it's potentially far better to use power ratings (as Vegas does) than to use power rankings.

For example, Buffalo could be ranked #1 and Miami #5, but those rankings could reflect the following ratings for example (with hypothetical power rating numbers included just to illustrate the point):

1. Buffalo 100
2. Team X 95
3. Team Y 93
4. Team Z 91
5. Miami 75
6. Team A 74

...and so on.

Miami is still #5, just four spots behind Buffalo, but the degree to which they're "less powerful" than Buffalo is better accounted for by the ratings (the hypothetical numbers I included) than by the rankings.

[Dave Gray]

^ Fair, but I feel like (just throwing out names), but a team like the Packers (who may be lower than us on these rankings) would maybe only be -3 at home.  Maybe I'm wrong about that.

I just think that it's pretty easy to see that YES, the Dolphins have played like a top 5 team but they overperformed to get there, so it's reasonable to think that Vegas and the betting public would understand that and adjust accordingly, but that adjustment wouldn't be in any kind of ranking system.

[Dolfanalyst]

^ Fair, but I feel like (just throwing out names), but a team like the Packers (who may be lower than us on these rankings) would maybe only be -3 at home.  Maybe I'm wrong about that.

I just think that it's pretty easy to see that YES, the Dolphins have played like a top 5 team but they overperformed to get there, so it's reasonable to think that Vegas and the betting public would understand that and adjust accordingly, but that adjustment wouldn't be in any kind of ranking system.

I think it's probably reflected in some ranking systems whereby the variance in rated team strength accounted for by early season performance is weighted fairly heavily in the Dolphins' case, but 2022 season expectation as a function of last year's performance is weighted comparatively less.  That's perhaps why you'd have Buffalo a very strong #1 as a function of their performance so far this season, in conjunction with what they did last year, with the Dolphins by contrast as a relatively "weak" #5 as a function of the same variables, with the Dolphins' 2021 season being far weaker.  Combine those two things and you get the near-TD spread we're seeing.

This is also why the Dolphins would tumble far lower than Buffalo would if either team suffered a convincing loss -- Buffalo has more "stability" on the basis of last year's performance.  For them such a loss would look like a fluke, whereas for the Dolphins it would make their previous wins this year look more like flukes.

[Spider-Dan]

Notice that for the 2021 NFL season the following system was best at predicting the outcomes of games against the spread:

https://rp-excel.com/

Their success rate against the spread in 2021 was .52918.
And they were one of the GOOD ones... for 2021, that is.  For 2020, they finished 51st out of 59, with a .48649 success rate against the spread.

The majority of the sources listed on that website were under .500 against the spread in 2021, which means they are somehow underperforming a coin flip.
The entire "industry" is indistinguishable from alchemy.

[Dolfanalyst]

Their success rate against the spread in 2021 was .52918.
And they were one of the GOOD ones... for 2021, that is.  For 2020, they finished 51st out of 59, with a .48649 success rate against the spread.

The majority of the sources listed on that website were under .500 against the spread in 2021, which means they are somehow underperforming a coin flip.
The entire "industry" is indistinguishable from alchemy.

And that's how they've paid the light bill in Vegas for about the past 70 years.