My Monday blog

John Kelly

Born Gambler
Staff member
Assigning a specific power rating to each of the 353 Division I college basketball teams is tricky business.

Not only is the workload extreme, but the work product is easily impeached.

It's more artwork than science in November and more science than artwork in March.

Of course, the mathematical assessments crystallize with more games and more data, but relying on one number to capture the changing nature of young adults playing amateur basketball is a substandard way to view the college hoop landscape.

In Ken Pomeroy's popular model, where every possession holds the same value and the entire season is viewed as one long game, the hole in his system is obvious.

A possession in the final minute of a 75-55 game cannot be viewed through the same prism as the first possession of an overtime game tied at 65.

Score context matters.

Moreover, a college basketball team accorded an abstract power rating of 80 may never play a single game at that level.

Assume the given team played five games which earned a rating of 90 on a scale of 100 and five games at 70.

Do you feel confident to attach a power rating of 80 to said squad?

Additionally, do you want to assign a home-court advantage of 3 or 3.5 points for every game on the team's schedule?

Why not a more nuanced rating for the site, spot and situation to reflect the atmosphere of the arena, the importance of the game and the level of competition?

A game against a hated rival in front of a sold-out arena on a Saturday night with ESPN cameras rolling figures to provide more of a boost than a mid-week game against a non-conference cupcake in a half-filled building when the students are on semester break.

Furthermore, what happens to a college basketball team in the game following a titanic showdown?

How do power ratings account for a letdown spot?

Should a college hoop team have one power rating for home games and another power rating for road games?

Power ratings from season-to-season are less meaningful today then ever before with the ever-changing rosters in the age of college basketball free-agency.

More than 2,000 players changed teams over the past three years compared to 1,300 transfers over the three-year period between 2008 and 2010.

Here's the central question regarding college basketball power ratings: What's the range between a team's best effort and worst effort and what factors influence whether a team will play its "A" game or throw a dud?

Sophisticated sports bettors have been asking these questions for decades while the NCAA, only in recent years, scrambles to find the best way to quantify teams most worthy of postseason play.

For years, the NCAA Selection Committee has struggled in two major categories: 1) Identifying 36 at-large berths for the bulky 68-team tournament field and 2) Assigning proper seeds to every member of the tourney.

The NCAA misses the mark by placing foolish restrictions on numerical evaluations in three areas of the relatively-new NET (NCAA Evaluation Tool) rankings.

In the NCAA's NET rankings, adopted before the start of last season, a 10-point win is considered exactly the same as a 20 or 30-point win.

Nonsense.

Why ignore any development on the playing field?

Simply employ a diminishing-returns principle that recognizes lopsided scores, places them in their proper light, but doesn't completely ignore them.

Furthermore, a game played in early November is assigned the same value as a game played in late February.

This is another imprudent feature of the NET ratings system.

Recent form is a critical factor in handicapping sports.

The NCAA champion is not always the best team but rather the team that's playing best, the team peaking at the season's most important time.

The champion is crowned in early April, not late November, and every NCAA basketball champion since 1985 is required to finish the season by winning six consecutive games.

Besides, the NCAA rewards its institutions with fame and fortune based on tournament wins accrued in March, not holiday tournament championships in December.

One last omission in the NET rankings: A team's travel schedule and rest days are not calculated into the NCAA formula.

Teams from power conferences load up their non-conference schedules with low-level D-1 teams that are forced to schedule away games as a way to balance their athletic budget.

Why not downgrade the performance of a rested Power 5 team when it defeats a squad playing its 13th consecutive road game?

These are not the only issues with math-based formulas.

Computer models also struggle to assess coaching prowess, roster versatility, team morale and under-the-radar injuries.

These critical handicapping factors are sometimes labeled "intangibles."

More nonsense.

In sum, forecasting models are only as good as the modeler's understanding of the subject.

Poor-quality input produces faulty outputs, furthering the likelihood of misleading results or useless predictions.

Like they say in the world of computer science, "Garbage in, garbage out."
 
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MrTop

EOG Master
JK , well done! bettors keep one eye on power ratings, location, scheduling, injuries , openers, closing numbers , etc. & the other eye on Cris.
 

jimmythegreek

The opening odds start here
You could be playing your best basketball heading into tournament time or right in the heart of it, but all it takes is one fundamental or legitimate mistake to change momentum as teams will use that spark to feed off of even the most improbable of situations to survive and advance. It's all about the 40 minute focus, one game at a time.
 

John Kelly

Born Gambler
Staff member
Good point, Jimmy.

The line between winning and losing is so fine.

The Virginia Cavaliers are the defending national champs and yet they were on the mat ready to be counted out a couple of times last season.
 
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John Kelly

Born Gambler
Staff member
JK , well done! bettors keep one eye on power ratings, location, scheduling, injuries , openers, closing numbers , etc. & the other eye on Cris.


And that's the way to do it, Top.

Some bettors focus on the games and ignore the market.

Others ignore the games and stare at the screen.

Why not be comprehensive in your approach?
 

Sportsrmylife

EOG Master
great write up and breakdown where there are holes in the market. the numbers are based on a "normalized" effort from each team but there are situations where effort is going to be much less given a previous game.

example. duke/nc game.

nc off a crushing loss to duke after a double digit let down in regulation and then a lead late in overtime had only 1 day to recover before heading to wake forest. while wake isn't a strong team given the numbers they smelled blood in the water (as I think Kane mentioned...they are still north carolina and wake is going to give a big effort) while NC was licking their wounds, shaking their heads by letting their biggest rival off the hook twice which could have been a small win on a disappointing season.

result was a wire to wire winner for wake forest bettors.

numbers don't account for these situations. rare but if spotted are good bets.
 

John Kelly

Born Gambler
Staff member
I can’t talk to modelers. Every answer is either noise or it’s factored in.


Frustrating, FW.

And the answer (noise or factored in) always supports their argument.

I have a friend who claims every piece of handicapping information is "in the number."

He's right most of the time.

Better team, better coach, home-field advantage, etc.

Those factors are baked in.

That's why bettors must focus on information that's revealed AFTER the pointspreads are released.

College football bowl games are a prime example of the above angle.

Injuries, suspensions, motivations and game plans are revealed after the release of opening numbers but well in advance of kickoff.
 
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KevinStott11

EOG Veteran
Fantastic work JK. They will never be able to quantify the choppiness and "caring" part of Sports. Nuance and Subtlety wreak havoc on (always changing if they are good) models. Love the part about a team's given range. Identifying teams that "suck" or "are good" consistently is an Art in itself and why I obsess with Chicago State and Kennessaw State. They almost always "play to form" (shit) and are easier to gauge then, say a Virginia whose perceived "range"" can be all over the place.

These variances seem much greater in College Sports, as the spreads always prove. Great critical thought piece. After watching CSU through the years, think they beat Kennessaw (and s/b ranked higher) this year and s/b ranked one spot higher than), by virtue of the Cougars Win at SIU-E and decent performance the game after at Tennessee St. (KSU also has 0 Surprise Wins). Choppiness screws up everything everywhere all the time. Driving on the Desert Inn Arterial proves this daily.
 

John Kelly

Born Gambler
Staff member
great write up and breakdown where there are holes in the market. the numbers are based on a "normalized" effort from each team but there are situations where effort is going to be much less given a previous game.

example. duke/nc game.

nc off a crushing loss to duke after a double digit let down in regulation and then a lead late in overtime had only 1 day to recover before heading to wake forest. while wake isn't a strong team given the numbers they smelled blood in the water (as I think Kane mentioned...they are still north carolina and wake is going to give a big effort) while NC was licking their wounds, shaking their heads by letting their biggest rival off the hook twice which could have been a small win on a disappointing season.

result was a wire to wire winner for wake forest bettors.

numbers don't account for these situations. rare but if spotted are good bets.


Final score: Wake Forest 74 North Carolina 57.

And to think the Tar Heels closed a 2-point road favorite.

Right now, UNC is dead last in the ACC standings.

Though Wake could be in trouble in its rematch with UNC tomorrow night at the Smith Center.

No perfect set-up for them tomorrow night.

In fact, the Tar Heels are playing well over the past week or so and it's Senior Night (Final home game for freshman Cole Anthony) in Chapel Hill.

UNC was 1-for-16 from beyond the arc in the first meeting three weeks ago.

UNC will be a 4-point choice with a total of 150, if you trust the Pomeroy model.
 

John Kelly

Born Gambler
Staff member
Fantastic work JK. They will never be able to quantify the choppiness and "caring" part of Sports. Nuance and Subtlety wreak havoc on (always changing if they are good) models. Love the part about a team's given range. Identifying teams that "suck" or "are good" consistently is an Art in itself and why I obsess with Chicago State and Kennessaw State. They almost always "play to form" (shit) and are easier to gauge then, say a Virginia whose perceived "range"" can be all over the place.

These variances seem much greater in College Sports, as the spreads always prove. Great critical thought piece. After watching CSU through the years, thinkk they beat Kennessaw (and s/b ranked higher), by virtue of the Cougars Win at SIU-E and decent performance the game after at Tennessee St. Choppiness screws up everything everywhere all the time. Driving on the Desert Inn Arterial proves this daily.


Ah yes, the Desert Inn Arterial.

Great metaphor, Kev.

I love your focus on Chicago State basketball.

Why know a little bit about all 353 teams when you can know everything about 10 or 12 teams?
 

FairWarning

Bells Beer Connoisseur
And that's the way to do it, Top.

Some bettors focus on the games and ignore the market.

Others ignore the games and stare at the screen.

Why not be comprehensive in your approach?
Only so many hours in a day. 150 of these teams shouldn’t be lined, but that’s my opinion. I have basically played 2H’s this year when I have had time.
 

FairWarning

Bells Beer Connoisseur
Final score: Wake Forest 74 North Carolina 57.

And to think the Tar Heels closed a 2-point road favorite.

Right now, UNC is dead last in the ACC standings.

Though Wake could be in trouble in its rematch with UNC tomorrow night at the Smith Center.

No perfect set-up for them tomorrow night.

In fact, the Tar Heels are playing well over the past week or so and it's Senior Night (Final home game for freshman Cole Anthony) in Chapel Hill.

UNC was 1-for-16 from beyond the arc in the first meeting three weeks ago.

UNC will be a 4-point choice with a total of 150, if you trust the Pomeroy model.
The same scenario was there this week with WF off an emotional win over hated Duke in 2OT. ND played at WF Saturday. I was all set to play ND when the ND pregame had mentioned that WF was undefeated in rematches this season, so I passed on ND.

WF is still undefeated in rematches.
 

Valuist

EOG Master
Fantastic work JK. They will never be able to quantify the choppiness and "caring" part of Sports. Nuance and Subtlety wreak havoc on (always changing if they are good) models. Love the part about a team's given range. Identifying teams that "suck" or "are good" consistently is an Art in itself and why I obsess with Chicago State and Kennessaw State. They almost always "play to form" (shit) and are easier to gauge then, say a Virginia whose perceived "range"" can be all over the place.

These variances seem much greater in College Sports, as the spreads always prove. Great critical thought piece. After watching CSU through the years, think they beat Kennessaw (and s/b ranked higher) this year and s/b ranked one spot higher than), by virtue of the Cougars Win at SIU-E and decent performance the game after at Tennessee St. (KSU also has 0 Surprise Wins). Choppiness screws up everything everywhere all the time. Driving on the Desert Inn Arterial proves this daily.

Really horrific teams are more consistently bad than top level teams are good. It doesn't get much worse than Chicago State or Kennessaw. Have to think good JUCOS could bury those two
 

ComptrBob

EOG Master
I would love to lay 4 with North car tommorow, game will close 6 or 7.


Opening line will be around NC -7 (Sagarin blended) or -8 (predictor). Hard to understand why JK continues to use broken KenPom crap.
 
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And that's the way to do it, Top.

Some bettors focus on the games and ignore the market.

Others ignore the games and stare at the screen.

Why not be comprehensive in your approach?

I don't think you can really read the market fully these days. Its too dispersed and far from complete information. Back in the day when every sharp was openly playing at Pinnacle there was something to be said about watching them and looking for leans that maybe told you something. Now few think its worth it and part of it comes from so much money not flowing through there as it was before. Because in reality one doesn't watch the market, they watch the flows of money entering the market and seeing what reaction that creates in the lines. Unless you have this info and have it for every market moving book, you just can't really be a market watcher to a highly valuable degree. You can see who the sharps appear to be taking some positions on, but its far from comprehensive.
 

John Kelly

Born Gambler
Staff member
Good point, Bill.

And it's hard to trust any information about "75% of the action is on Team A" or "75% of the 'tickets written' on Team B."

I wince when I hear that applied as a method for picking winners.

I understand the philosophy but I don't trust the information.
 

John Kelly

Born Gambler
Staff member
Opening line will be around NC -7 (Sagarin blended) or -8 (predictor). Hard to understand why JK continues to use broken KenPom crap.


I did not mean to endorse Pomeroy over Sagarin.

In fact, I employed the disclaimer, "...if you trust Pomeroy."
 
Good point, Bill.

And it's hard to trust any information about "75% of the action is on Team A" or "75% of the 'tickets written' on Team B."

I wince when I hear that applied as a method for picking winners.

I understand the philosophy but I don't trust the information.

Yeah no kidding. As Krackman said if that information was really useful, do you think books would even consider sharing it?
 

John Kelly

Born Gambler
Staff member
Years ago, some sports books in Las Vegas liked to pull the plug on their odds feed in the final hour of NFL wagering so as to deal only to squares, not sharps.

Tsk tsk.
 

ComptrBob

EOG Master
Overall, very good blog. Just forget KenPom for predicting lines.

Obviously, power rating models from the NCAA have evolved from the crappy RPI to somewhat better NET. The committee has to use seat of the pants adjustments that vary from year to year to get anywhere close to an "acceptable" ranking. Bookmakers tend to follow Sagarin plus adjustments, they used to overvalue the big favorites at tournament time, not so much anymore. Also by eliminating the old "Bracket Buster" games, we get fewer bubble mid-majors that have a shot to improve their record.

Some modelers have algorithms to gradually unweight "stale" data and project "point distributions" for a game instead of using just one number.
 

John Kelly

Born Gambler
Staff member
Sagarin switched his model a few years ago to look more like Pomeroy's.

For years, Sagarin did not use offensive and defensive efficiency numbers.
 

Viejo Dinosaur

EOG Master
Great blog JK....l never stop learning about gambling philosophies and info....nice info and analysis by some smart gamblers in this thread....
 

Viejo Dinosaur

EOG Master
Great blog JK....l never stop learning about gambling philosophies and info....nice info and analysis by some smart gamblers in this thread....
 

Foresthill

EOG Addicted
Sagarin switched his model a few years ago to look more like Pomeroy's.

For years, Sagarin did not use offensive and defensive efficiency numbers.


I don't think this assertion is correct. Where did you read this?

From Sagarin's website moments ago:

"Teams that appear to be tied to two decimal places in a given column are actually
different when carried to more decimal places in the computer's internal arithmetic.

----------------------------------------------------------------------------------------------------------------
The PREDICTOR, is such that the score is the only thing that matters.
PREDICTOR is also known as PURE_POINTS, BALLANTINE, RHEINGOLD, WHITE OWL
and is a very good PREDICTOR of future games.
----------------------------------------------------------------------------------------------------------------
GOLDEN_MEAN also utilizes the actual SCORES of the games in a different way but is also completely SCORE BASED
and thus should be a good match for the PURE POINTS in terms of predictive accuracy for upcoming games.
----------------------------------------------------------------------------------------------------------------
The RECENT, is score-based and weights RECENT play more heavily than earlier games. Its effect will become
more pronounced the longer a season goes if a given team happens to have an upward or downward trend.
----------------------------------------------------------------------------------------------------------------
The overall RATING is a synthesis of the three different SCORE-BASED methods, PREDICTOR(PURE_POINTS), GOLDEN_MEAN,
and RECENT and thus should be a good predictor in its own right."

As Sagarin states above all 4 ratings (Predictor, Golden Mean, Recent, and the Rating which is a blend of the other three) are calculated on the score:

Predictor -- "the score is the only thing that matters."
Golden Mean -- "utilizes the actual SCORES of the games in a different way but is also completely SCORE BASED"
Recent -- "is score-based and weights RECENT play more heavily than earlier games."
Rating -- "a synthesis of the three different SCORE-BASED methods, PREDICTOR(PURE_POINTS), GOLDEN_MEAN,
and RECENT"

Sagarin mentions nothing about incorporating offensive and defensive efficiency numbers in his ratings.
 

John Kelly

Born Gambler
Staff member
Before the start of the 2019 college hoop season, Sagarin started to list totals for all college basketball games on the USA Today website.

I assumed Sagarin follows a model similar to Pomeroy's where pace and efficiency are combined to predict the total number of points scored in a game.

How else would he arrive at a college hoop total?
 

waco

EOG Dedicated
Im a dog bettor and I think the dogs will be barking for march madness. I will keep track
 

Foresthill

EOG Addicted
Before the start of the 2019 college hoop season, Sagarin started to list totals for all college basketball games on the USA Today website.

I assumed Sagarin follows a model similar to Pomeroy's where pace and efficiency are combined to predict the total number of points scored in a game.

How else would he arrive at a college hoop total?

At sagarin.com he has predictions, including totals, at the bottom of, in this instance, the college basketball ratings page. As far as I know, he states no where how he calculates the totals. And the fact that he has total predictions doesn't mean he uses the same data set for the game and total predictions, respectively.

He also has separate game predictions using Eigen Vector analysis (these sometimes differ radically from his "classic" ratings predictions) at the bottom of his predictions section below the 4 ratings predictions and total predictions output.

From my limited anecdotal observances, I would use Pomeroy's efficiency numbers and pace numbers for both teams to calculate a theoretical total -- and then interpret that number in relation to the current line to decide if I want to bet a total over, under, or not -- instead of using Sagarin's total number. That seems to be more accurate than what ever total number Sagarin comes up with (again, his methodology seems unknown to me).

I'm with ComptrBob when it comes to which ratings to use to predict games (Sagarin's), though I calculate my own Pomeroy number for the what the spread should be for an additional data point of information to consider. Anecdotally, by this time of year, both those spread numbers tend to converge anyway.

I'm sure Bob's "go to"numbers are his own, not Sagarin's, just that he thinks Sagarin's are more accurate than Pomeroy's -- with his preference obviously being his own numbers.

By the way, Sagarin's had totals associated with the predictions at the bottom of the page for several seasons now -- not just starting in 2019.
 
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ComptrBob

EOG Master
Sagarin is pretty secretive about all his formulas. He does say he uses "starting values" at the season's beginning until the "graph theory nodes" are filled.

I would not assume he uses any particular stat to project totals. Most books back in the 90's ignored pace and just used the average scores of the two teams to get a starting number and I would say there are many ways to predict a total for a game.
 
Sagarin is pretty secretive about all his formulas. He does say he uses "starting values" at the season's beginning until the "graph theory nodes" are filled.

I would not assume he uses any particular stat to project totals. Most books back in the 90's ignored pace and just used the average scores of the two teams to get a starting number and I would say there are many ways to predict a total for a game.

Bob, just curious, once you are in the middle of the season, what is the biggest difference in base power rating between yours and Sagarin's? Does it ever get more than 2 points? Obviously ignoring current injuries or factors you use to consider for a particular game, just trying to get a sense of how much can these developed models possibly diverge on teams once you get past the early season adjustments.
 

MrTop

EOG Master
Before the start of the 2019 college hoop season, Sagarin started to list totals for all college basketball games on the USA Today website.

I assumed Sagarin follows a model similar to Pomeroy's where pace and efficiency are combined to predict the total number of points scored in a game.

How else would he arrive at a college hoop total?



one of these guys puts it up before saragin -
College Basketball Ranking Composite
 
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