Expected Points Added (EPA): The NFL’s Game-Changing Metric

14 February 2025

Football is a game of inches, strategy, and, perhaps most importantly, numbers. But beyond the yard markers and touchdowns, there's an advanced stat that's slowly but surely changing how we analyze the game: Expected Points Added (EPA). If you’re a die-hard NFL fan, or a stats geek who loves diving deep into the intricacies of football metrics, you’ve probably heard the term thrown around. But what exactly is EPA, and why is it becoming the go-to metric for evaluating players and teams?

In this article, we’ll break down what EPA is, how it works, and why it’s quickly becoming one of the most important stats in football. By the end, you’ll have a solid grasp of how this stat can change the way you watch the NFL.

What is Expected Points Added (EPA)?

Okay, let’s keep it simple. Expected Points Added is a way to measure how much a specific play increases or decreases a team's chances of scoring. It’s essentially a tool to quantify the impact of every single play on the scoreboard. The stat goes beyond basic numbers like yards gained or lost and asks a more fundamental question: How did this play affect the team's chance to score points?

Let’s break it down step-by-step:

The Concept of Expected Points

At any point during a game, based on your field position, down, distance, and time remaining, a team has an "expected" number of points they're likely to score on that drive. For example, if a team has the ball at the opponent’s 10-yard line on first down, they have a pretty high chance of scoring a touchdown. If they’re at their own 1-yard line, the expected points are much lower.

Adding or Subtracting Points

EPA measures the difference between the expected points before and after a play. If the play moves the ball closer to scoring (like a 20-yard pass), EPA goes up. If the play worsens the team’s field position (like a sack or interception), EPA goes down. Essentially, it answers: How much closer—or further—did this play get the offense to scoring points?

Why It’s Game-Changing

Traditional stats like total yards or touchdowns don't tell the full story of how valuable a play was in the context of the game. For instance, a 5-yard run might seem insignificant, but if it converts a 3rd-and-4, it’s incredibly valuable because it keeps the drive alive. EPA takes these nuanced factors into account, giving us a clearer picture of a play’s importance.

How is EPA Calculated?

Now, let’s dive into the nitty-gritty. How on earth do you calculate something as abstract as “adding points”? Don’t worry, you don’t need to whip out your calculator; computers do the heavy lifting here. But knowing the basics of the formula can help you appreciate the stat even more.

The Math Behind It

At its core, calculating EPA involves determining the difference between the Expected Points (EP) before and after a play.

1. Pre-Play Expected Points: This is the number of points a team is expected to score at the start of the play, based on their current field position, down, and distance. These values are derived from years of historical data.

2. Post-Play Expected Points: After the play, a new Expected Points value is determined based on the updated field position, down, and distance.

3. EPA Formula: Simply put, EPA = Post-Play EP - Pre-Play EP.

A Real-Life Example

Let’s say a team has the ball on the opponent’s 50-yard line, 1st-and-10. Based on historical data, the expected points for this situation might be 2.0. Now, imagine the quarterback throws a 25-yard pass, and the team is now at the 25-yard line. The new expected points might jump to 4.5. The EPA for this play would be:

- EPA = 4.5 (Post-Play EP) - 2.0 (Pre-Play EP) = +2.5 EPA

That means this play added 2.5 expected points to the offense.

Now, let’s say on the next play, the quarterback is sacked, pushing the team back to the 35-yard line. Maybe the new expected points drop to 3.0. The EPA for that sack would be:

- EPA = 3.0 (Post-Play EP) - 4.5 (Pre-Play EP) = -1.5 EPA

This tells us that the defense made a significant impact by reducing the offense’s chance of scoring.

Why EPA is Better Than Traditional Stats

If you’ve been a football fan for a while, you’re probably used to seeing stats like yards, touchdowns, and QB rating to evaluate players and teams. So why all the fuss about EPA? Here’s why EPA is a superior metric:

1. Context Matters

Yards are great, but they don’t always tell the full story. A 10-yard gain on 3rd-and-15 doesn’t help much, but a 10-yard gain on 3rd-and-9 is crucial. EPA provides context for each play, recognizing that not all yards are created equal.

2. Performance Under Pressure

EPA shines when it comes to evaluating how teams perform in high-leverage situations. Converting a 4th-and-1 near midfield is much more valuable than a 5-yard run on 1st-and-10 from your own 10-yard line. EPA captures these differences, helping to identify which teams and players excel when it matters most.

3. Valuing Defensive Plays

EPA isn’t just for offense! Defensive plays like interceptions, sacks, and forced fumbles can have a massive impact on a game. With EPA, we can quantify how much these defensive efforts hurt the opposing offense’s chances of scoring.

4. Predictive Value

Studies have shown that EPA is a better predictor of future performance than traditional stats. In a league where teams are constantly looking for any edge they can get, understanding EPA can help identify trends that basic stats might miss.

How NFL Teams and Analysts Use EPA

It’s not just nerdy math guys using EPA to crunch numbers in their basements—NFL teams and analysts are using it to make real-time decisions. From play-calling to evaluating player performance, here’s how EPA is being utilized in the league:

1. Play-Calling Decisions

Coaches and analysts use EPA to determine the most beneficial plays in certain situations. For example, they might find that passing on 1st down has a higher EPA than running, even though traditional football wisdom says to establish the run early. This shift in thinking has led to a more pass-heavy NFL in recent years.

2. Evaluating Quarterbacks

EPA is particularly useful for gauging quarterback performance. Instead of just looking at a QB's passing yards or touchdowns, EPA accounts for the context of each play. A QB who consistently makes plays that move the offense closer to scoring is far more valuable than one who racks up yards in garbage time.

3. Assessing Defenses

Defenses can also be evaluated using EPA. A defense that consistently forces negative EPA plays (like sacks and turnovers) is much more valuable than one that simply limits yards. EPA helps identify which defenses are actually stopping scoring opportunities, not just bending but not breaking.

4. Real-Time Game Strategy

Teams are increasingly using real-time data to inform decisions like whether to go for it on 4th down, attempt a field goal, or punt. EPA data can help coaches make more informed decisions that maximize their chance of winning.

Limitations of EPA

As groundbreaking as EPA is, it’s not without its flaws. No stat is perfect, and EPA is no exception. Here are a few of the limitations to keep in mind:

1. Doesn’t Measure Everything

EPA is great for measuring scoring potential, but it doesn’t capture everything. For example, it doesn’t account for special teams play or penalties that don’t directly affect the field position (like holding calls). These factors can still influence a game.

2. Limited by Historical Data

EPA calculations rely heavily on historical data, which means they might not always reflect the current state of the game. As the NFL evolves, the expected points model will need to be updated to reflect changes in strategy and scoring trends.

3. Not Always Intuitive

For casual fans, EPA can be a bit hard to grasp at first. It’s not as straightforward as basic stats like yards or touchdowns, and it requires a deeper understanding of probability and game theory. But once you get the hang of it, it becomes an invaluable tool for understanding the game.

Conclusion: The Future of Football Analytics

Expected Points Added is more than just a buzzword for the analytics crowd—it’s a revolutionary way to understand football. By focusing on how much each play impacts the team’s chances of scoring, EPA provides a clearer, more accurate view of player and team performance. As the NFL continues to embrace analytics, EPA will likely become a staple in how we talk about the game.

So, next time you're watching a game and see a big play or a critical 4th-down conversion, think about how much EPA that play just added (or subtracted). It might just change the way you see football.