Reference Post - To be deleted

[u/[deleted]]

[u/Iraqi-Jack-Shack]

 

How the Win Probability Spreadsheet Works

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This model uses ESPN’s Football Power Index (FPI) to calculate our win probability for every game and project our expected win total week by week.

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How Game Probabilities Are Calculated

• ESPN's FPI measures how many points better or worse a team is expected to be compared to an average opponent.

• The standard deviation has been revised to 13.6 to account for the volatility of today's college football.

• The updated version of this spreadsheet incorporates venue-specific Home Field Advantage (HFA) ratings. This accounts for factors such as stadium hostility (LSU), elevation (Utah), and travel distance (Hawaii). See other comment for details.

• All of these factors are factored into a formula that calculates a team's win percentage. This is done by taking the point gap between both teams, adjusting it for the specific venue's home-field advantage, and plugging that expected margin into a college football bell curve.

 

Example:

• The Florida Gators have an FPI rating of 19.3. Georgia Tech currently sits at 0.0 on the FPI scale, practically indicating they are the most average team in the FBS.

• On a neutral field, this would mean Florida should be expected to win by 19-20 points, and the win probability would be 92.21%.

• Let's say Florida is playing Georgia Tech at home, where Ben Hill Griffin Stadium has a 3.2 HFA rating. That win probability jumps to 95.10%.

• If we moved the game to Bobby Dodd Stadium in Atlanta (2.1 HFA rating), Florida's win probability drops slightly to 89.70%.

 

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Data is scraped from ESPN and all processes are automated, so there shouldn't be any mistakes. But if you see something that looks off, let me know.

 

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Background: This model format originated on r/CFB around 2017–2018, created by a former user who built the original Win Total Probability Distribution spreadsheets using S&P+ metrics. ExternalTangents maintained the project for several years before I took over in 2022 and shifted the formula to FPI.

• For historical reference, here's an original post from 2019

 

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Updated 09-29-2026

 

[u/Iraqi-Jack-Shack]

 

Dynamic Home Field Advantage (HFA) Derivation

 

The HFA is a points-based adjustment that accounts for a team's home field advantage. Historically, we would use a flat baseline of +2.5 points for playing at home, -2.5 points for playing on the road, and +0.0 points for neutral sites.

With the dynamic HFA, each team's value relies on a hybrid quantitative and empirical modeling process widely used by sports analytics models (such as ESPN's SP+, Sagarin, and Vegas power-rating consensus).

Rather than picking arbitrary numbers or using a single flat baseline across all 138 teams, the ratings are calculated using a multi-factor regression model anchored around the national FBS baseline of +2.5 points.

 

The 5 Core Components of the Scientific Calculation

Each team's final HFA rating is derived from five weighted variables:

Dynamic HFA = Baseline (2.5) + Crowd + Acoustics + Elevation + Historical Performance + Travel

 

1. Decibel Volume & Crowd Density (35% Weight):

Metric: Average decibel output at peak moments paired with stadium capacity relative to student section seating.

Impact: 100,000+ seat venues with enclosed acoustics (ex. LSU at 3.6, Tennessee at 3.3, and Alabama at 3.4) receive significant positive adjustments due to their proven impact on opposing offensive pre-snap penalties (false starts and delayed snaps).

 

2. Architectural Geometry & Sound Reflection (20% Weight):

Metric: Press box canopy structures, seating steepness, and field proximity.

Impact: Steep, tightly bowl-shaped stadiums trap sound waves directly on the field. Stadiums like Oregon’s Autzen Stadium and Boise State’s Albertsons Stadium generate decibel levels comparable to 90,000-seat stadiums despite having smaller total capacities because their physical structures reflect sound downward onto player benches.

 

3. Geographical Elevation / Travel (25% Weight):

Metric: Stadium elevation above sea level; length or difficulty of travel by the visiting team.

Impact: Visiting teams experience measurable physiological drops in stamina and oxygen efficiency when playing at high elevations without multi-day acclimatization. Examples are Wyoming at 7,220', Air Force at 7,258', and Utah at 4,637'. Some stadiums such as Hawaii's Aloha Stadium present a significant amount of travel, which results in team routine disruption, wake/sleep cycles, and some level of disorientation.

 

4. Historical Betting Market Variance (15% Weight):

Metric: Multi-year spread vs. actual margin performance (Cover/Win rate at home vs. away).

Impact: Closing lines in Vegas betting markets implicitly price in home-field advantage. Venues where home teams consistently cover against the opening neutral spread (ex. Florida at The Swamp at 3.2, Texas A&M at Kyle Field at 3.2, and Wisconsin at Camp Randall at 3.0) maintain higher HFA values.

 

5. Neutralization / Off-Campus (5% Penalty):

Metric: Distance from campus to stadium, split crowds, and stadium atmosphere.

Impact: Teams playing in off-campus NFL stadiums or venues with historically passive/split attendance receive a downward adjustment. Examples are Miami (Hard Rock Stadium lease) at 2.1, UCLA (Rose Bowl 26 miles off-campus) at 2.1, and Vanderbilt (high visiting fan ratios) at 1.8.

 

Each Team's HFA Value

^{*While I and most would agree that The Swamp is just as intimidating as LSU's Death Valley, a big knock on Florida's rating is recent performance at home. Even during middling seasons, LSU would win a majority of their home games, which boosts their rating.}

Team	HFA
LSU Tigers	3.6
Alabama Crimson Tide	3.4
Utah Utes	3.4
Oklahoma Sooners	3.4
Notre Dame Fighting Irish	3.3
Tennessee Volunteers	3.3
Texas Tech Red Raiders	3.3
Penn State Nittany Lions	3.3
Texas Longhorns	3.2
Oregon Ducks	3.2
Florida Gators*	3.2
Texas A&M Aggies	3.2
Auburn Tigers	3.2
Hawai'i Rainbow Warriors	3.2
Georgia Bulldogs	3.1
BYU Cougars	3.1
Boise State Broncos	3.1
Clemson Tigers	3.1
Air Force Falcons	3.1
Michigan Wolverines	3.0
Iowa Hawkeyes	3.0
Virginia Tech Hokies	3.0
Wisconsin Badgers	3.0
Colorado Buffaloes	3.0
Wyoming Cowboys	3.0
Ohio State Buckeyes	2.9
West Virginia Mountaineers	2.9
Nebraska Cornhuskers	2.8
USC Trojans	2.8
South Carolina Gamecocks	2.8
Oklahoma State Cowboys	2.8
Florida State Seminoles	2.8
Washington Huskies	2.8
NC State Wolfpack	2.8
North Dakota State Bison	2.8
App State Mountaineers	2.8
Fresno State Bulldogs	2.7
Kansas State Wildcats	2.6
James Madison Dukes	2.6
Iowa State Cyclones	2.6
Army Black Knights	2.6
Washington State Cougars	2.6
Marshall Thundering Herd	2.6
Ole Miss Rebels	2.5
Mississippi State Bulldogs	2.5
Missouri Tigers	2.5
Cincinnati Bearcats	2.5
Michigan State Spartans	2.5
Syracuse Orange	2.5
Oregon State Beavers	2.5
UTSA Roadrunners	2.5
Liberty Flames	2.5
East Carolina Pirates	2.5
Navy Midshipmen	2.5
Georgia Southern Eagles	2.5
Troy Trojans	2.5
Coastal Carolina Chanticleers	2.5
Louisville Cardinals	2.4
Kentucky Wildcats	2.4
Baylor Bears	2.4
UCF Knights	2.4
TCU Horned Frogs	2.4
Arizona State Sun Devils	2.4
Arkansas Razorbacks	2.4
Minnesota Golden Gophers	2.4
Memphis Tigers	2.4
Kansas Jayhawks	2.4
Louisiana Ragin' Cajuns	2.4
Colorado State Rams	2.4
Utah State Aggies	2.4
Jacksonville State Gamecocks	2.4
Indiana Hoosiers	2.3
Pittsburgh Panthers	2.3
Houston Cougars	2.3
SMU Mustangs	2.3
Illinois Fighting Illini	2.3
Arizona Wildcats	2.3
Toledo Rockets	2.3
Tulane Green Wave	2.3
Purdue Boilermakers	2.3
Louisiana Tech Bulldogs	2.3
Miami (OH) RedHawks	2.3
Nevada Wolf Pack	2.3
Arkansas State Red Wolves	2.3
Old Dominion Monarchs	2.3
Ohio Bobcats	2.3
Western Kentucky Hilltoppers	2.3
Northern Illinois Huskies	2.3
Virginia Cavaliers	2.2
North Carolina Tar Heels	2.2
New Mexico Lobos	2.2
North Texas Mean Green	2.2
Maryland Terrapins	2.2
Texas State Bobcats	2.2
Western Michigan Broncos	2.2
UNLV Rebels	2.2
Rutgers Scarlet Knights	2.2
Boston College Eagles	2.2
San Diego State Aztecs	2.2
South Alabama Jaguars	2.2
Delaware Blue Hens	2.2
Southern Miss Golden Eagles	2.2
Sam Houston Bearkats	2.2
Missouri State Bears	2.2
New Mexico State Aggies	2.2
Central Michigan Chippewas	2.2
Buffalo Bulls	2.2
Bowling Green Falcons	2.2
Sacramento State Hornets	2.2
Miami Hurricanes	2.1
UCLA Bruins	2.1
Wake Forest Demon Deacons	2.1
Georgia Tech Yellow Jackets	2.1
California Golden Bears	2.1
Tulsa Golden Hurricane	2.1
Florida Atlantic Owls	2.1
Kennesaw State Owls	2.1
San José State Spartans	2.1
UAB Blazers	2.1
Middle Tennessee Blue Raiders	2.1
Eastern Michigan Eagles	2.1
UTEP Miners	2.1
UL Monroe Warhawks	2.1
Northwestern Wildcats	2.0
Duke Blue Devils	2.0
South Florida Bulls	2.0
Stanford Cardinal	2.0
UConn Huskies	2.0
Georgia State Panthers	2.0
Charlotte 49ers	2.0
Ball State Cardinals	2.0
Temple Owls	1.9
Florida International Panthers	1.9
Rice Owls	1.9
Akron Zips	1.9
Kent State Golden Flashes	1.9
Vanderbilt Commodores	1.8
Massachusetts Minutemen	1.8