Decision Making in American Football : Evidence from 7 Years of NFL - PowerPoint PPT Presentation

Decision Making in American Football : Evidence from 7 Years of NFL Data Konstantinos Pelechrinis Presented by Ke Zhang ECML/PKDD Machine Learning & Data Mining for Sports Analytics Riva del Garda, Italy 2016

COACHING DECISIONS

ARE COACHING DECISIONS RATIONAL?

WHAT IS A RATIONAL DECISION? A decision that maximizes the probability of winning

WHAT IS A RATIONAL DECISION? A decision that maximizes the probability of winning In the vast majority of the cases this is equivalent to maximizing the points scored

WHAT IS A RATIONAL DECISION? A decision that maximizes the probability of winning In the vast majority of the cases this is equivalent to maximizing the points scored The closer to the end of the game the less good the above approximation

TWO CASE STUDIES PAT decision 4th down decision

DATA NFL API • 7 years play-by-play data • 1,792 regular season games • 42,371 drives • 316,630 snaps • 9,021 touchdowns

PAT DECISION OR

PAT DECISIONS

PAT DECISIONS E[p]= 2*

PAT DECISIONS - 1* E[p]= 2*

PAT DECISIONS - 1* E[p]= 2* 6 10 5 22 24 0.50 14 14 10 13 9 Expected Point Gain 0.25 15 12 14 18 12 12 12 0.00 15 11 16 16 21 14 24 17 -0.25 22 14 14 9 13 21 11 -0.50 ARI ATL BAL BUF CAR CHI CIN CLE DAL DEN DET GB HOU IND JAC KC MIA MIN NE NO NYG NYJ OAK PHI PIT SD SEA SF STL TB TEN WAS

PAT DECISIONS - 1* E[p]= 2* 6 10 5 22 24 0.50 14 14 10 13 9 Expected Point Gain 0.25 15 12 14 18 12 12 12 0.00 15 11 16 16 21 14 24 17 -0.25 22 14 14 9 13 21 11 -0.50 ARI ATL BAL BUF CAR CHI CIN CLE DAL DEN DET GB HOU IND JAC KC MIA MIN NE NO NYG NYJ OAK PHI PIT SD SEA SF STL TB TEN WAS

4TH DOWN DECISION

4TH DOWN DECISIONS

4TH DOWN DECISIONS 1.2 4th down converstion success rate 0.8 0.4 0.0 -0.4 0 10 20 30 Yards to go

4TH DOWN DECISIONS 1.2 4th down converstion success rate 0.8 0.8 Probability of FG Success 0.4 0.4 0.0 0.0 -0.4 0 10 20 30 20 30 40 50 60 70 Distance (yards) Yards to go

4TH DOWN DECISIONS 1.2 4th down converstion success rate 0.8 0.8 Probability of FG Success 0.4 0.4 0.0 0.0 Touchback line 1.00 -0.4 0 10 20 30 20 30 40 50 60 70 Distance (yards) Yards to go Probability of Success 0.75 type TD 0.50 FG Fail 0.25 0.00 0 25 50 75 100 Distance to Goal Line at the Beginning of the Drive

4TH DOWN DECISIONS

4TH DOWN DECISIONS Touchback 4 Expected Points Gained 2 0 -2 0 25 50 75 100 Distance to the Goal Line when 4th down

CONCLUSIONS & LIMITATIONS • Coaching decisions seem to follow the status quo rather than being rational • Coaches of course might not want to maximize the points score but rather minimize the variance for the points scored • Current analysis is only focused on offensive unit decisions • Objective: maximize the point differential • The estimates of the fourth down conversion rate can be biased as alluded to above

Every snap is a data point! http://fivethirtyeight.com/features/the-high-school-football-coach- who-never-punts/ Questions can be directed to kpele@pitt.edu @kpelechrinis 13

4TH DOWN DECISIONS