Professional football has already been forced to grapple with the fallout from COVID-19, causing major changes to the NFL Draft and the cancellation of in-person workouts during the offseason, then ultimately the entire preseason. If the NFL is able to successfully hold a 2020 season, it will look far different than anything that has come before it.
After a week or two of regular season play, gamblers will have to quickly adjust to the new normal based on the data available. Until we have that data in hand, we're going to have to do our best to think through the ramifications of playing football during a pandemic. Today, the topic we're diving into is home-field advantage.
CBS Sports NFL insider Jonathan Jones took a close look at the impact of having limited to no fans in the stands all the way back in May, and the final part of his three-piece series focused on the effect on home-field advantage. I'd highly encourage you to check out his reporting, and we're going to build on it here as part of my annual look at the role home-field advantage plays in projecting NFL lines week in and week out.
Before we dive into our specific process for 2020, here's a quick primer on why HFA matters. Historically, oddsmakers have treated HFA as being worth three points, meaning when two evenly-matched teams play, whichever one is at home will be favored by three points. However, HFA has been worth less on average in recent years due to a variety of reasons, and the value of HFA differs team by team (for example, most fans understand it's tougher to be a road team playing the Vikings in Minnesota than it is the Chargers in Carson, California).
I joined host Will Brinson and to break down every team's home-field advantage (along with more betting tips for 2020) on the Pick Six Podcast; listen below, and be sure to subscribe for daily NFL goodness.
Calculating home-field advantage (2015-19)
Each offseason, I put together a weighted home-field advantage (wHFA) formula that takes points scored and allowed over the last five years for each team and gives a diminishing weight the further you go back in time.
(While I think other data exist that is better for predicting future performance than points scored and allowed, the benefit of using these numbers is that we're already dealing with the scale we want to use for our final output. Otherwise, we'd have to find a way to calculate a conversion rate for another stat to points scored to help us determine what it all means for our point spreads.)
In August of last year, my raw wHFA calculations had the average team at 2.31 points heading into the 2019 season. This year, that number takes a severe dip, because on average there essentially was no home-field advantage in 2019. The home team won just 51.7% of its games last season, the lowest mark since 1972, per the New York Times. Banging the road team proved a fruitful strategy for bettors, as home teams went just 104-137-10 against the spread, per Pro-Football-Reference data.
The shocking performance of teams on the road has essentially cut my overall raw wHFA numbers in half: the average team only had 1.15 points of home-field advantage over the last five years in my weighted formula. That result makes sense; if HFA was non-existent last year, and the most recent year in the weighted formula counts for 50 percent, then you would expect the top-level output (which was 2.31 a year ago) to be reduced by around 50 percent.
Now, what does this mean moving forward? We don't treat any of our output as the end-all, be-all of the discussion around home-field advantage. Our formula tracks how much better each team is at home than on the road, and when it turns out a team has been better away from home (as nine teams are this year), I don't assign them a negative home-field advantage when I'm building my projected lines every week.
But if you think the pandemic will cause home-field advantage to be largely wiped out, it does make some sense to use 2019's extreme results, where home-field advantage was largely wiped out, as indicative of what to expect in 2020. I've taken the middle path; my average home-field calculation heading into the season is 1.75 points, much lower than the 2.4-2.5 range I typically sit around, but higher than the raw data implies.
Below, you'll find a table with every team's wHFA from 2015-19, then what I'm estimating that team's home-field advantage will be in 2020. I'll be using these numbers along with my power ratings each week to determine what I believe the lines should be at the beginning of the week. If there's a large discrepancy between my line and the posted line, that's an indicator it's time to make a move.
I'll cover some specific cases after the table, but for now, the data:
The pandemic tax
The casual betting fan considers home-field advantage worth three points, but you'll note above that I have zero teams getting a three-point advantage or higher at home. I do think playing at home will carry some type of advantage even if there are limited to no fans in the stands.
While the home team will lose the crowd edge, they will have the benefit of going about their normal routine in the run up to a game at home, while the road team has to take part in travel, which brings about increased interactions outside of their home routine. As a result, road teams must be vigilant about social distancing, dining interactions, etc. in order to deliver a healthy team to the stadium on gameday. Certain teams with strong leadership should have little issue doing that, while others run the risk of creating an outbreak in their locker rooms and the loss of multiple key players before kickoff.
Theoretically, there's a scenario where being the home team is actually way more advantageous during the pandemic, but we'll have to wait and see whether that's borne out in practice. For now, my HFA range is between one and 2.5 points.
Colts take the crown
When I Dolphins had proven the most extreme example of a team being better at home than on the road. While no one reached their heights in a year defined by road play, the Colts have emerged as the best wHFA team in football, thanks largely to a massive gap in points against at home and on the road in 2019. The year before, it was the Colts offense that scored many more points at home than on the road, and in 2017, the defensive side was leading the charge with an extreme home/road split. If the pattern holds -- not that there's any reason it should -- you should expect great things from Philip Rivers and Co. at home in 2020., the
The Raiders had one of the best wHFAs in the league last year, and they did not disappoint, with the team playing much better at home during its final season in Oakland, particularly on the defensive side of the ball. As a result, they rank in the top three of wHFA in 2020, behind the Colts and the Steelers. Of course, that doesn't mean a whole lot when the team is abandoning its old home for the glamour and glitz of Las Vegas.
But anyone who has been to Vegas knows the city was home to plenty of Raiders fans even before the move, and anyone that saw the community rally around the NHL's Golden Knights knows the franchise will be embraced wholeheartedly by the city. For that reason, even though I can't give the Vegas iteration of the franchise credit for what it did during its Oakland years, I still have them a half-point better in HFA than I do the two Los Angeles teams.
In this space last year, we talked about five teams being underwater in wHFA, meaning the weighted formula pegged them better on the road than at home. With 2019's massive outlier in road performance, the number of road warriors has ballooned to nine teams.
Some of those nine won't come as a shock. The Washington Football Team has been weighed down by a poor home-field advantage for years. The Rams and Chargers still wind up looking like road teams in their home stadiums depending on their opponents. But two of the three teams with the worst wHFA may come as a shock: the Baltimore Ravens and New Orleans Saints.
The Ravens weren't bad at home like some of the other teams in this category, they were just awesome on the road, where they beat teams by scores of 59-10 (Dolphins in Week 1), 49-13 (Bengals in Week 10) and 45-6 (Rams in Week 12). They did destroy the Texans at home 41-7 and added a blowout home win over the Jets 42-21, but for the most part, Baltimore was unstoppable on the road. The three years prior, they've shown to be a better team at home, so I'm not getting carried away with their adjustment despite the team checking in with the second-lowest wHFA in the league.
The Saints typically deliver more than 30 points per game at home, and the offense easily produces better point totals in New Orleans than on the road. Neither was the case last year, however, and when added to the fact that their defense is consistently worse at home than on the road, the Saints are probably given too much credit for being a home powerhouse. Don't overvalue them at home, and don't undersell them on the road.
Don't get carried away
Just because we saw one extreme in 2019 doesn't mean it has to continue for a team in 2020. If we didn't have a pandemic to worry about, I'd say we could probably assign most teams a HFA of somewhere between two and 3.5 points, which is a far more conservative scale than what the wHFA output suggests.
My numbers are certainly better than just giving the home team three points in every game. But they're not perfect. If you use them to help stay ahead of the books, great. If you use the ideas behind them to put together a better system, even better.
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