Frequently Asked Questions
Common questions about NFL analytics, sports betting strategy, fantasy football optimization, and football data science.
Getting Started with Analytics
What is EPA in football analytics?
EPA (Expected Points Added) measures the value of each play in terms of expected points. It calculates the difference between the expected points before and after a play. A positive EPA means the offense gained value, while negative EPA means the defense won.
EPA is the most important metric in modern NFL analytics and is widely used for sports betting and fantasy football analysis.
How do I get started with football analytics?
Start with free tools: nflfastR provides play-by-play data in R, and nflverse offers a complete ecosystem. Learn basic R or Python for data analysis.
Begin by understanding EPA and success rate - these form the foundation of modern analytics. This textbook provides a complete 45-chapter guide from basics to advanced machine learning techniques.
What data sources are best for NFL analytics?
The best free source is nflverse/nflfastR, which provides play-by-play data with EPA calculations back to 1999. For tracking data, NFL Next Gen Stats provides speed and separation metrics.
Paid sources include PFF (grades), Sports Info Solutions (charting), and TruMedia (comprehensive platform).
Sports Betting Questions
How can I use NFL analytics for sports betting?
NFL analytics improves betting by identifying value in lines:
- Use EPA and success rate to evaluate team efficiency beyond win-loss records
- Analyze situational data like fourth-down tendencies
- Compare implied probabilities to analytical win probability models
- Identify mismatches using advanced metrics
How accurate are NFL prediction models?
The best public NFL models achieve 65-70% accuracy against the spread, compared to ~52.4% needed to profit. Point spread predictions average 10-13 points MAE.
The NFL has high variance due to small sample sizes (17 games) and injuries. Combining multiple models often outperforms any single approach.
Should teams go for it on fourth down more often?
Yes. Analytics strongly suggests NFL teams should be more aggressive. Expected value calculations show going for it is often +EV even at midfield with 2-3 yards to go.
Fourth-down decision models are among the most robust findings in football analytics.
Fantasy Football Questions
How can analytics help my fantasy football team?
Analytics improves fantasy through:
- Target share and air yards for predicting receiver production
- Snap counts and opportunity metrics for identifying breakouts
- Matchup analysis using defensive EPA allowed by position
- Red zone usage rates for touchdown regression
- YPRR (Yards Per Route Run) for finding undervalued receivers
What is the best metric for evaluating NFL quarterbacks?
The best QB evaluation combines multiple metrics:
- EPA per play - overall efficiency
- CPOE - accuracy isolated from scheme
- Air yards metrics - aggressiveness
For fantasy, add rushing value. For betting, focus on EPA against different coverages and pressure rates.
Advanced Metrics Questions
What is win probability in NFL analytics?
Win probability (WP) estimates a team's chance of winning based on: score, time remaining, field position, down, and distance.
WPA (Win Probability Added) measures how much each play changed win probability. These metrics are essential for live betting and evaluating clutch performance.
What is DVOA and how does it differ from EPA?
DVOA (Defense-adjusted Value Over Average) is Football Outsiders' metric that compares plays to a baseline and adjusts for opponent strength.
EPA measures raw expected points without opponent adjustment. EPA is freely available; DVOA provides better team rankings but is proprietary.
What is success rate in football analytics?
Success rate measures plays achieving "success" based on down:
- 1st down: gain 40% of needed yards
- 2nd down: gain 60% of needed yards
- 3rd/4th down: gain 100% (convert)
Unlike EPA, success rate measures consistency and isn't skewed by big plays.
Industry Questions
How do NFL teams use analytics?
NFL teams use analytics for:
- Fourth-down and two-point conversion decisions
- Player evaluation and draft picks
- Contract negotiations and salary cap
- Game planning and opponent tendencies
- In-game strategy adjustments
Teams like the Eagles, Ravens, and Browns have been analytics leaders.
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