Hot Hand Research in Its Fourth Decade Alan

Hot Hand Research in Its Fourth Decade Alan Reifman, Texas Tech University 2017 Great Lakes Analytics in Sports

Definitions Success: Making shots in basketball, getting hits in baseball, rolling strikes in bowling, beating par on golf holes, etc. Fans, coaches, and players may use the term “hot hand” simply to refer to a player who has succeeded many times in a row. Statisticians typically use a specific criterion for a hot hand: A player has a higher probability of success on the next attempt if he or she has just succeeded than if he or she has just failed. Often written as: p (success | past success) > p (success | past failure) A previous success is thought to give player greater confidence, help him or her maintain concentration, etc.

Second Half Field-Goal Attempts (2 or 3 PT) of Kobe Bryant’s 81 -Point Game (January 22, 2006) Conditional on Last Prior Attempt: p (hit|hit) = 13/18 =. 72; p (hit|miss) = 5/8 =. 63 Shots After 1 Hit Actual Sequenc e Shots After 1 Miss H H H H M H M H H H M M H H H H M M M H H H M Can also condition on hitting/missing last two attempts, last three attempts, Shots etc. After 1 Hit Actual Sequenc e Shots After 1 Miss H H H H M H M H H H M M H H H H M M M H H http: //www. 82 games. com/kobe 81. htm H M

No. of Hot Hand Studies Over the Years 12 10 8 6 4 2 0 1985 1990 1995 2000 2005 2010 2015 2020 Articles citing Gilovich et al. (1985) and containing an empirical study of sports performance after success or failure. Bibliography available through my website.

Let’s take a quiz at this point: Pat, an established 37% shooter on three-pointers, makes three in a row in a game. What would you expect Pat’s shooting percentage on threes to be for Pat’s next few shots: (a)A few percentage points lower How I’d than have 37% (b) Still 37%, give or take answered a few years ago How I’d answer now (c)A few percentage points higher than 37% (d)Several percentage points higher than 37%

Gilovich, Vallone, & Tversky (1985) OVERALL

Limitations of Gilovich et al. (1985) Study of 76 ers* • Didn’t control for shot distances – player could shoot from greater distance after hitting a few consecutive shots due to overconfidence, which would work against hot streak. • Didn’t control for how closely guarded a player was – player who has hit a few consecutive shots could draw tighter defense, again working against hot streak. *The article contained two additional shooting studies, one with Celtics’ FT data & the other involving a controlled shooting session with Cornell players.

WER STUDY TO ADDRESS SOME OF THESE ISS

Reading Between the Lines: How Sport. VU Cameras Are Revolutionizing the NBA Robbie Loeb https: //www. slideshare. net/robbieloeb/rloeb-pptsportvu

BOCSKY ET AL. (2014)

[…John] […SKIP…] BOSTON GLOBE (2014) https: //www. bostonglobe. com/ideas/2014/02/09/the-hot-hand-might-realafter-all/N 8 V 34 b. GLWh. Pqk 0 Sx 9 yo. HWI/story. html

LAST MONTH ON ESPN. COM (June 12, 201 CITES 2015 STUDY BY MILLER & SANJURJ

LET’S GO BACK TO 2015

Miller & Sanjurjo (2015)

Miller & Sanjurjo (2015) Analysis of NBA All-Star 3 -PT Contests (With Correction to Overcome Systematic Understatement of Hot-Hand Effect) Accuracy Gain After 3 Straight Hits (“Hotness”) No. of Contestants . 34 1 . 20 to. 22 3 . 14 to. 18 4 . 11 to. 12 5 . 06 to. 07 3 . 05 2 . 01 to. 04 10 Negative 5 16 players improved by more than. 05 (5%) from their usual base rate after hitting 3 straight MEDIAN 15 improved by less than 5% (or even did worse than usual) after 3 straight hits

2017 (AFTER ESPN. COM ARTICLE)

Findings from Other Sports • Summary from my 2011 book: “streakiness will occur most readily with relatively simple motions (e. g. , bowling, golf putting) that can be repeated quickly, so that motor memories of the action can be retained …” (p. 131) • Selected developments post-2011 o 2016 study by Green & Zwiebel suggests (contrary to prior research) that there may be streak-hitting in MLB game data (e. g. , “the difference between a recent on-base percentage of. 100 and. 500 (representing a recent cold run and hot run respectively) translates to an increased probability of getting on base of… 2. 5%, or 25 OBP points”). o In-depth case study of NFL’s Peyton Manning (Bullard, 2016): “Peyton was actually less likely to complete a pass if he had a higher complex heat [higher percentage of his last four passes completed than would be statistically expected, factoring in difficulty of attempt]. ”

Outstanding Issues in Hot Hand Research • Streaks that defy usual pattern of coming from top-level athletes or teams • Team dynamics (e. g. , “contagion”) from one player to another

“Long streaks always are, and must be, a matter of extraordinary luck imposed upon great skill. ” Indeed, prominent streaks are usually. Harvard amassedpaleontologist by athletes and teams who, even without – Stephen Jay Gould (1941 -2002), (and sometimes statistical their respective streaks, would be considered among the finest practitioners of their writer) sports • Baseball hitting streaks (at least one hit in consecutive games) o Joe Di. Maggio’s record 56 -game hitting-streak in 1941 (compiled season-specific batting averages between. 323 -. 381 from 1936 -1940); o Wee Willie Keeler, second-longest hitting streak (45 games, 1896 -97), batted. 371 and. 377 in the two prior seasons o Pete Rose, third-longest streak (44, 1978), batted ≥. 300 in 12 of 13 seasons before streak. • College basketball winning streaks o John Wooden’s UCLA men’s basketball teams winning 88 straight games in the 1970 s (program had already won 6 NCAA titles before start of this streak) o Geno Auriemma’s UConn women, separate win streaks of 111, 90, and 70 straight (program had already won 2 NCAA titles before first of these streaks) • Tiger Woods making the cut in 142 straight pro golf tournaments

So Where Does a Streak Like This – in a Mediocre Team – Come From? 16 -game win streak Prior 11 -9 record After win streak, 23 -23 (5 reg. , 4 OT losses) (19 reg. , 4 OT losses) Previous season: 34 -48 (40 reg. , 8 OT losses) Two play-off appearances in first 15 seasons (2000 -01 to 2015 -16; http: //www. hockey-reference. com/ NHL lock-out 200

Five-Thirty-Eight on Other “Out of Nowhere” Hot Performances “[Scooter] Gennett [who hit 4 homers in a game on June 6, 2017] is the baseball equivalent of Devin Booker scoring 70 points in an NBA game, or Nick Foles tossing seven touchdown passes in the NFL. Part of why we watch sports is that in any given game there’s the chance that a mediocre middle infielder might explode for one of the best offensive performances ever. ” https: //fivethirtyeight. com/features/scooter-gennett-issomehow-not-the-most-random-player-to-hit-four-hrs/

Team Dynamics in Long Winning Streaks The 2013 L. A. Dodgers had a 42 -8 midseason stretch (June 22 -August 17), tied for the third-best 50 -game sequence in MLB history (the two better ones occurred in 1906 and 1912). The key was getting superior performances from many players at once. Quoting from my own “Seamheads” article on the Dodgers’ run: • Outfielder Yasiel Puig, whose June 3 Dodger debut predated the scald by a couple of weeks, recorded OPS numbers of 1. 180, . 789, and. 920, in June, July, and August, respectively. • Shortstop Hanley Ramirez, who hardly played at all in April or May due to injury, put up OPS values of 1. 086 and 1. 065 in June and July… • Pitcher Zack Greinke, who missed action early… and then needed several starts to find his groove, finally did so. In 16 starts from July 8 to the end of the regular season, Greinke allowed more than 2 earned runs only once. • Fellow starter Clayton Kershaw was similarly brilliant. In 16 starts in June, July, and August, he allowed more than 2 earned runs twice. • Reliever Kenley Jansen “completed a hidden perfect game…, setting down exactly 27 batters in a row over 10 appearances from July 23 to August 8. . ” (ESPN/Grantland) http: //seamheads. com/blog/2013/11/26/scalding-50 -gamestretches-in-mlb-history-and-how-teams-did-immediately-

(Public Library of Science) Hitting Is Contagious in Baseball: Evidence from Long Hitting Streaks • Joel R. Bock , • Akhilesh Maewal, • David A. Gough Batting while teammate currently has ≥ 30 -game hitting streak. “Negative values along the abscissa correspond to batting before the streak hitter. ” Figure 5. Mean BA versus relative lineup position. http: //journals. plos. org/plosone/article? id=10. 1371/journal. pone. 005 1367

e-mail: alan. reifman@ttu. edu https: //twitter. com/alanreifman http: //thehothand. blogspot. com

SHAMELESS PLUG (2011 BOOK)