After years of scattering explanations for our advanced stats in articles that have to be linked back to, this Glossary is a long-time coming. Each statistic that we use for advanced stats is here, and some example box scores are posted at the bottom.

Expected Points Added (EPA)

Football is much more complicated for advanced stats compared to basketball or baseball. In basketball, a successful offensive possession ends with points, and little else matters if that’s not how the possession ends. But in football, that’s not always the case. That’s because individual plays are much more distinct from drives than basketball’s distinction between individual plays (an offensive rebound, for example) and possessions. A 40-yard run play is a very good play even if the drive does not end in points. The play should not be punished because of the plays that follow. Offensive rebounds are dime a dozen; 40-yard runs are not.

In basketball, the points are scored when the ball goes through the hoop, but in football, the key play that led to the touchdown may have occurred long before the play that actually scores the touchdown. That means we need to assign values to each play on a drive, not just the scoring play.

We do this using Expected Points, which takes the average net points scored by the offense on the drive given the down, distance, and yardline. A team that has 1st-and-10 at their own 25 can be expected to score a net of 1.73 points. I say net because it’s based on the next points, which could be scored by the other team. These EP values are calculated based on years and years of data. Down, distance, and spot on the field are the three inputs.

So how can we use this to grade plays? Say a team has an EP of 1.73 on 1st-and-10 at their 25. On first down, they gain nine yards. That sets up 2nd-and-1 and their 34, which has an EP of 1.96. Simple math incoming: that play “created” +0.23 points. That’s called Expected Points Added, or EPA. By the time a long drive reaches the endzone, it’s been filled with plays of both positive and negative EPA that add up to the total value created on the drive. If a drive features a 40-yard run, that play probably had a larger EPA than the touchdown itself. High-leverage plays like explosives and third/fourth down conversions generally have the largest EPA.

You’ll see stats like EPA per Play and EPA per Drive that give general quality of play-level and drive-level efficiency.

WEPA

Weighted Expected Points Added, or WEPA, is a very complicated but more predictive value that tries to adjust for “noise” in the play-by-play data. It adjusts EPA per Drive with the following modifications:

• Max EP. Rather than use the ending Expected Points (7 for touchdown drives, something close to zero for non-scoring drives, depending on where the drive ended) for a drive, WEPA uses the maximum: basically, the closest you got to scoring. For touchdown drives, the max and ending EP are the same, but for drives that end with less than a touchdown, how close you got matters. The regular Drive EPA of a 14-play, 74-yard drive that fails on downs at the opponent 1 will be slightly negative, but the Max EP was probably around 6.5, leading to a Drive WEPA of something like +5. The assumption is that repeated failures to finish good drives with actual points is a bit fluky.
• Series conversion adjustments. A “series” is a set of downs. Getting a first down creates a new series. Teams that are bad on first and second down often fall behind the chains. If they use explosives on later downs to keep converting, that’s fluky, and WEPA punishes them for it. It takes the final EP of each series and subtracts from it the minimum EP of that series.
• Explosive touchdown adjustments. The offense only gets a share of the EPA gained on scoring plays, so 1-yard touchdowns are preferable to 80-yard touchdowns. The reason is that 80-yard touchdowns are harder to replicate. A game that features multiple breakaway touchdowns might be a fluky result that isn’t predictive.

WEPA is used to calculate noise-adjusted final score, which is just an “adjusted” final score where WEPA is used instead of EPA. Occasionally it will “flip” the game winner, suggesting that the actual winner benefitted from a little bit of luck. We also use WEPA to calculate our overall predictive grades that helps us forecast future games.

Efficiency and Explosiveness

• Success Rate is the basic measure of efficiency. It is the percentage of a team’s offensive plays that are successful; basically, it is how good the offense is at staying on schedule. “Success” is defined as any play that generates positive EPA. It doesn’t matter how positive the play is: as long as it generates positive EPA, it is successful. The numbers you see in regular articles have been adjusted for opponent quality.
• Explosive Play Rate is our basic measure of, well, explosiveness. It’s the percentage of plays that quality as explosive: runs of 10+ yards and passes of 20+ yards.

These two stat work together to tell a story. If you have a good EPA per Play, you did you do it? Because you had a ton of huge plays (explosiveness), or because you methodically moved down the field, staying on schedule (efficiency)?

Run & Pass Stats

Because the EPA system is so all-inclusive, we need more focused stats to break down very specific parts of an offense. These are those stats.

• Short Yardage Success Rate is the success rate of run plays in short-yardage situations: third or fourth down and one or two yards to go. This measure is mostly about the offensive line’s ability to get a push.
• Stuff Rate is the percentage of run plays stopped for zero yards or less. Like success rate, this number is a yes/no question (“Was the play stopped for no gain or a loss?”) meaning that it measures efficiency more than explosiveness. High-efficiency running backs and good offensive lines have low stuff rates, while high-explosiveness running backs and bad offensive line have high ones.
• Line Yards are the rushing yards credited to the offensive line. The offensive line is credited with 125% of lost yards, 100% of yards gained 0-3, and 50% of yards gained 4-6, so the maximum line yards on any play is 4.5 (a run of 6+ yards). This cap at six yards is in place because the offensive line is, in theory, only responsible for the first six yards. Yards after that skew the averages and are more about downfield blocking and the running back’s open-field skill. Good offensive lines have high line-yard averages. If this stat is significantly better than the next two stats, that’s a sign that your offensive line is better than your running backs in the run game.
• Opportunity Rate is the percentage of run plays that gain at least four yards. All runs to hit four yards are potential home-run hitters. The more a back generates runs of 6+ yards, the more likely he is to break a long one. This stat is single most important run-related stat (besides Rush EPA itself, of course).
• Bonus Yards per Opportunity is the average yards gained beyond four for any opportunity run. Think of it this way: the first four yards of any run are basically “line-yards” and all yards after that are “bonus-yards”. So a 16-yard run is worth 4.5 line-yards and 12 bonus-yards. It doesn’t work perfectly but it’s close enough. This statistic is only calculated if the run is considered an opportunity. Explosive backs always have high bonus-yards. If this stat is significantly better than line-yards, that’s a sign that your running backs are better than your offensive line in the run game.

Now for the passing stats:

• Adjusted Net Yards per Attempt (ANY/A) is the average yards per pass attempt (sacks are pass attempts, too) with one caveat: touchdowns are worth 20 yards and interceptions are worth minus-45. These are not random numbers: they are the result of significant calculation into the ‘yardage value of a touchdown’.
• Sack Rate is the percentage of dropbacks at end in a sack. This may be the most obvious stat on this list.
• Adjusted Net Yards per Target (ANY/T) is just ANY/A but for receivers. Targets are used as the denominator.

Other stats

We’ll use a few other interesting stats in our analysis.

• Marginal Third Down Conversion Percentage is third down conversion percentage adjusted based on the yards to go. Converting a 3rd and 1 is easier than converting a 3rd and 13, right? A logarithmic equation ( 0.7294 – 0.192 * ln(yards to go) ) gives you the chance. For example, a 3rd and 3 has a 48.1% chance of conversion. A positive marginal third down percentage means that the offense converted more third downs than expected, while a negative percentage means they converted fewer.
• Misery Rate is the percentage of a team’s offense plays that include a lost fumble, an interception, or a sack. When calculated from the defense’s perspective, we call this havoc rate.
• Leverage Rate is the percentage of offensive plays that the offense is “on-schedule”. This is done by divided all plays into two groups: standard downs and passing downs. Passing downs are situation where a pass seems obvious: 2nd down and more than 7, or 3rd/4th down and more than 3. Every other play is a standard down. One goal of an offense is to keep its leverage rate (percentage of standard downs) as high as possible, so the defense has to keep guessing.

We will also do the “Big 3” stats (EPA, success, explosiveness) for both standard and passing downs, to understand where the offense was better. Leverage rate helps contextualize that. You’ll also see run rate, which is the percentage of plays that are runs.

Drive-level stats

These stats deal with the success or failure on a drive level.

• Available Yards is the percentage of yards gained by the offense out of the total possible. There is a maximum number of yards an offense can gain in a game based on the start of each drive. For example, if an offense starts at midfield (so, 50 available yards) and stalls out at the 30, then it picked up 40% of the available yards (20 out of 50). As you can see, this much better than “yards gained per drive” because it accounts for where the offense started.
• Points per Drive is the basic measure of the offense’s ability to get points.
• Scoring Chance % is the percentage of a team’s drives that include a first down inside the opponents’ 40-yard line. Once you get a first down inside the 40, you need to score.
• Points per Scoring Chance measures how good the offense was at converting scoring chances into points. It’s important for measuring one of football’s key factors: finishing drives.

Putting it all together

Now that we’ve met all the stats, let’s see them in action. Here’s the 2025 Arkansas-Arkansas State game.

You can see that Arkansas dominated this game, even if the 56-14 final score is slightly more lopsided than the way the actual game played out, as Arkansas benefitted from a ton of explosive plays.

Here we see Arkansas dominated standard downs (first downs, second and medium or short, plus third and short) with 32 successful plays in 47 tries, averaging 12.1 yards per play and 0.64 EPA per play. Arkansas State had much worse leverage (70%, compared to Arkansas’ 82%), which means they had a lot more plays in passing situations (22).

Arkansas dominated the run game, but the lopsided part of this is the last stats: highlight yards. Arkansas only had two additional successful rushes and two additional explosive rushes, but their best runs were so much better. Winning highlight yards 225-92 is the main reason this game was so lopsided. Arkansas’ 21 runs of four-plus yards (opportunity runs) averaged 14.7 yards per rush (10.7 highlight yards plus the first four yards for each). That’s more than 300 rushing yards right there!

Zero explosive passes in 38 dropbacks for A-State were certainly interesting in this game.