Friday, August 28, 2020

Review of the "Other" Hot Hand Book

I have just finished reading The Hot Hand, a March 2020 release by Wall Street Journal writer Ben Cohen. I had cornered the market on hot hand books from 2011-2020 (see image in right-hand column), but I welcome Mr. Cohen's book. Actually, I feel the two books are very different. Whereas mine was devoted entirely to sports and contained many statistical analyses, the new book delves into many areas outside of sports (e.g., art, the stock market, detective work) and, with one crucial exception (discussed later), is fairly light on mathematics, statistics, and probability.

I found Cohen's examination of where hot hands appear to exist (or not exist) to be fair and well-contextualized. That doesn't mean I agree with every conclusion in the book, but I think the overall tone was appropriate.

There are two main themes (as best I can tell) that tie together the sports and non-sports examples throughout the book. One is how the conventional wisdom on a given question can change at any point (e.g., is there or is there not a hot-hand effect beyond chance? is a particular painting truly from a great master or a fraud?), sometimes going back-and-forth multiple times. The second theme is how ongoing advances in technology (e.g., high-speed sky-cam videos of basketball games; x-rays of paintings) can contribute to changes in conventional wisdom.

From a sports perspective, the book ends with a one-two punch that argues for a hot hand in basketball shooting. One is a 2014 study by three extremely savvy Harvard undergraduates, who used sky-cam video data of NBA games to take into account, with great specificity, the difficulty of each shot (distance from the hoop, defensive presence, etc.), which the earliest studies of NBA shooting could not do (here and here). 

The Harvard study found a roughly two percent improvement in future shooting success coming off of a couple of makes. In Cohen's words, "While the result itself was modest, the meaning of it was monumental" (p. 204). I must demur. Over the past few decades, there has been a movement in psychology and related fields to emphasize effect-sizes -- how much impact one variable has on another or how strongly do two variables correlate. Hence, I'm inclined to assign modest importance to a finding of modest magnitude. The Harvard researchers themselves described their own results as a "small blaze" (p. 204).

Next to enter the scene were the young economists Josh Miller and Adam Sanjurjo. Miller and Sanjurjo's intellectual contribution -- discovering a counter-intuitive and heretofore undetected bias in seemingly basic statistical calculation -- is certainly formidable. Yet, as I wrote in 2015, I find the practical magnitude of Miller and Sanjurjo's insight to be relatively modest, as well.

If a basketball shooter had a long-term track-record of 50% on three-pointers and then made a few in a row, the standard analytic approach pre-Miller-Sanjurjo would have been simply to assess whether the player hit shots at a greater clip than 50% for some number of shots after the initial set of consecutive makes. It turns out, however, that the proper baseline for judging success after a hit for a long-term 50% shooter is actually not 50%, but 42%. As Cohen succinctly puts it, "If a 50 percent shooter was shooting 50% [over the long term], he was actually beating the odds" (p. 227).

The following graph from one of Miller and Sanjurjo's working papers conveys this idea visually (their derivations are far above my mathematical expertise). The graph is divided into three sections, one for when a player's true probability of success is .75 (top), one for when his or her true probability is .50 (middle), and one for when his or her true probability is .25 (bottom). The key thing to look at is the vertical discrepancy between a given dashed line (representing true probability) and the solid color lines. Each color line, which is a function of the total number (n) of shots in a sequence and the length (k) of a hot streak, tells us the new baseline to use in judging a player's future shooting success.

A concrete example should help. I have annotated the graph to highlight a particular point on the top red curve: For a true .75 shooter, who has made five shots in a row, in a sequence of 20 shots. As shown at the end of the grey horizontal line I added from the target data-point to the y-axis, that player should be judged against a standard of .61 for whether he or she is "hot" over his or her next sequence of shots. Reiterating Cohen's explanation (above), a player who shot, say, .66 or .72 would be considered "hot" (i.e., above .61), even though the player's underlying true shooting percentage is .75.

Miller and Sanjurjo note that "as n gets larger, the difference between expected conditional relative frequencies and respective probabilities of success generally decrease..." In other words, the bias they demonstrated tends to diminish with an increasing number of shots and, under certain conditions, approaches zero. Note that, with a sequence of 100 shots and a p = .75 underlying probability, the colored lines start getting really close to the dashed line. Miller and Sanjurjo add, though, that if an athlete has compiled a very long streak (k = 5 straight hits, depicted above in red), even with a very long sequence (n = 100), a substantial bias can remain (e.g., for a p = .50 shooter, there is still a .15 bias, namely .50 on the dashed line, minus .35 on the red line).

One question I have about Miller and Sanjurjo's formulation is how it maps onto fan psychology. As we've seen, a 50% shooter who follows up a few straight hits with, say, a sequence of 47% success is mathematically hot (i.e., exceeding the adjusted baseline of 42%). Yet, I can't imagine fans following the reasoning (as correct as it is) that, "Hey, this 50% shooter is now hitting 47%. He (or she) is on fire!" 

A quibble I have with Cohen is his lack of discussion of sports other than basketball. Solid evidence for a sports hot hand has been around since 2004, in the case of professional bowling (Dorsey-Palmateer & Smith, 2004). Cohen knew about this study, as it is included in his bibliography for The Hot Hand (p. 271).

Hot hand research has now been going on for 35 years, dating from the famous Gilovich, Vallone, and Tversky (1985) study. I can see research progressing in several directions, such as the aforementioned fan psychology and more research with actual game data. There is also research showing -- opposite of Miller and Sanjurjo -- that certain hot-hand estimation methods may overstate the extent of a hot hand (Cotton, McIntyre, & Price, 2016). Thus, some of the analytic formulations may have to be reconciled. Lastly, Cohen's epilogue followed Tom Gilovich as he was conducting some new studies. I eagerly await what he has to report. In short, there's plenty of grist for the hot-hand research mill. I'm currently 57 years old, so I would have to live to 92 to see if hot-hand research makes it another 35 years!

Wednesday, May 29, 2019

New Study by Bill James on General Offensive Streakiness

Bill James has conducted and posted on his website a new study of players' general offensive streakiness in baseball. Using a large sample of player-years (e.g., Lou Brock in 1967), James ranked a given player's games in a given year from highest to lowest runs-created. As James explains:

Let us suppose that the player plays 160 games; we rank the 160 games 1 to 160 in order of the number of runs that he has created in each game, and we divide those into his 80 best games and his 80 worst games.

Labeling each of the 80 best games as "good" and each of the 80 worst games as "bad," James then looked at the player's games in chronological sequence, identifying consistent sequences (e.g., good-good-good or bad-bad) and inconsistent sequences (e.g., good-bad-good). Consistent sequences were given positive point-values, larger the longer the stretch, whereas inconsistent sequences were given negative values, more sharply negative the longer the stretch.

The results? "The average player in the study played 141 games, with an average of positive streak score of 139, and a negative streak score of 131.5." Stated differently, "There are 34,683 cases within the data in which a player followed a good game with a good game or a bad game with a bad game, and 33,626 cases in which the two games did not match—50.8% 'matches', 49.2% 'non-matches'." 

James characterizes the results as showing "some clustering of good games and bad games within a player’s season." The difference seems pretty small, though. Further, James acknowledges several possible extraneous factors that could affect clustering, including playing the same (good or bad) opponent multiple games in a series. I would focus more specifically on quality of pitching. If batters faced the mid-1990s Atlanta Braves with Greg Maddux, Tom Glavine, and John Smoltz pitching on successive days, you bet they would be highly likely to exhibit a clustering of subpar offensive games!

Tuesday, April 09, 2019

Cronin Takes Over UCLA Basketball Program That Has One Post-Wooden National Title: A 44-Year Odyssey

Today's hiring of Mick Cronin as UCLA men's basketball coach provides an opportunity to dissect a cold streak in Bruin basketball, namely one national championship in the past 44 years, following a Golden Age of 10 titles in 12 years (1963-64 to 1974-75). Cronin succeeds interim coach Murry Bartow, who succeeded Steve Alford, who was fired this past New Year's Eve. 

Alford's Bruin teams made the NCAA Sweet Sixteen three times in his five full seasons at the helm, a better record than Cronin's in getting to this round. Developments in Westwood over the past four months naturally raise questions over the state of the program and the demandingness of the fan base.

Lurking behind any discussion of UCLA basketball, of course, is the program’s success under the legendary coach John Wooden. It was under Wooden, who ended his 27-year stint on the Bruin bench with the aforementioned 10 national championships in 12 years. The tenth title (in 1974-75) came in particularly dramatic fashion, as Wooden had announced shortly after UCLA’s win in that year’s national semifinal that the upcoming championship game vs. Kentucky would be the last game he would ever coach.[1] 

The Bruins rarely lost at all in the early 1970s, compiling an 88-game win streak that ended in 1974. Further, a new ranking of all 81 NCAA men's hoops champions in history (the most recent entry being Virginia) placed Wooden-era UCLA teams in the 1st, 3rd, 5th, 6th, 11th, 17th, 18th, 19th, 23rd, and 37th positions.

Presumably, few UCLA fans are today clamoring for Bruin coaches to defy reality by winning 10 national titles in 12 years. However, that seemed to be the standard in the mid-late 1970s. Wooden’s immediate successors, with records decidedly better than Alford’s, felt the heat harshly and quickly and left for other gigs. 

Gene Bartow (father of Murry), the first post-Wooden UCLA coach, went 27-5 and made the Final Four in 1975-76, then went 24-5 in 1976-77. There was no third year in Westwood for Bartow, as he left to become the founding coach of a new program at the University of Alabama-Birmingham.

The next coach, former Bruin assistant Gary Cunningham, went 25-3 and 25-5 the next two years (making the Elite Eight in 1978-79), before leaving for a small college in Oregon to launch what became a long career in Division I athletic administration. According to Los Angeles Times reporter Mark Heisler’s 1996 book They Shoot Coaches, Don't They? UCLA and the NCAA Since John Wooden, Cunningham had actually decided after one season to give it up, but secretly told UCLA he would coach one more year to give the school more time to find its next coach. 

Former UCLA and NBA player Keith Erickson, in his book Champions Again! about the 1994-95 Bruin team, simply noted that Wooden’s immediate successors “were at the wrong place at the wrong time” (p. 66).

UCLA has now had 10 head basketball coaches  in the 44 seasons since Wooden retired, including the interim skipper Murry Bartow. Only once since Wooden’s retirement has UCLA won a national tile, in 1995 under Jim Harrick. Post-Wooden Bruin teams have appeared in three national championship games (1980, 1995, and 2006) and six Final Fours (1976, 1980, 1995, 2006, 2007, and 2008). Only one of the 10 coaches, Ben Howland, brought back a sense of sustained success (albeit without a national championship), leading the Bruins to three consecutive Final Four appearances in 2006, 2007, and 2008. 

The questions concerning the past four decades of UCLA basketball abound. In the following sections, I raise and attempt to answer these questions as best I can.

Why hasn’t UCLA produced at a higher level over the past 44 seasons?


Could UCLA’s failure to contend for more post-Wooden national championships stem from a lack of coaching talent? One way to evaluate general coaching ability – independent of how a given coach did at UCLA – is to examine his coaching record in other jobs. First, a good coach, given sufficient time to recruit and implement his or her system, should be able to win a sizable majority of games just about anywhere. Second, UCLA offers many competitive advantages in recruitment and resources (e.g., championship legacy, location in a large city, nice campus, good academics), so coaches’ records in their non-UCLA head coaching jobs arguably offer a more accurate picture of their underlying abilities absent these advantages. Of the nine post-Wooden coaches (excluding Murry Bartow), seven held head-coaching jobs at other schools. The following table shows their records.

How UCLA’s Post-Wooden Coaches* Fared at Other Places
Coach (UCLA Years)
Other Jobs
Record (Non-UCLA)
Gene Bartow (1975-76 – 1976-77)
Memphis, Illinois, UAB
440-243 (.644)
G. Cunningham (1977-78 – 1978-79)
Larry Brown (1979-80 – 1980-81)
Kansas, SMU
220-83 (.726)
Larry Farmer (1981-82 – 1983-84
Weber State, Loyola-Chicago
105-156 (.402)
Walt Hazzard (1984-85 – 1987-88)
Jim Harrick (1988-89 – 1995-96)
Pepperdine, Rhode Island, Georgia
279-172 (.619)
Steve Lavin (1996-97 – 2002-03)
St. John’s
92-72 (.561)
Ben Howland (2003-04 – 2012-13)
N. Arizona, Pitt, Mississippi State
233-147 (.613)
Steve Alford (2013-14 – mid 2018-19)
Missouri State, Iowa, New Mexico
385-206 (.651)
   *Excluding 2019 interim coach Murry Bartow.

One can safely say that these coaches represented a range of abilities and accomplishments, but some were clearly excellent coaches. Larry Brown, who later won an NCAA title at Kansas and an NBA title with Detroit, would have to be considered among the all-time coaching greats on the court. However, his wanderlust – having coached nine NBA and three college teams – and record of NCAA rules violations detract from his accomplishments. Harrick and Howland, two of UCLA’s better post-Wooden coaches in terms of postseason success, also had various off-the-court problems (Harrick, Howland).

The remaining coaches were, to my knowledge, free of scandal. Gene Bartow had an impressive overall record, not only taking UCLA to the Final Four, but also leading Memphis State (now just Memphis) to the 1973 national-title game, where it lost to UCLA. Cunningham showed a lot of promise in his brief coaching stint, but his career interests lie elsewhere. Lavin and Alford were solid, although each enjoyed only modest postseason success (Lavin led one team, UCLA in 1997, to the Elite Eight, whereas no Alford team at any Division I school went beyond the Sweet Sixteen).

For the most part, then, the quality of the post-Wooden UCLA coaches was high. Instead, the real problem seems to be instability on the Bruin sideline, both in terms of the frequent turnover of coaches and the off-the-court problems with which some of them were involved. For whatever reason, coaching stints of 20 years or longer at the same school are quite rare today. Within power conferences, only Jim Boeheim, Mike Krzyzewski, and Tom Izzo fit the bill.

Someone who was never far from the revolving door of post-Wooden UCLA coaching, but who never actually entered it, was former Bruin assistant Denny Crum. Crum, of course, had left UCLA after the 1971 tournament to begin a 30-year head-coaching run at Louisville that yielded two national titles (1980, over UCLA in the final, and 1986) and six Final Four appearances. According to one source, longtime UCLA athletic director J.D. Morgan disliked Crum and opted for Bartow, who more resembled Wooden in background and personality. Crum claimed to have been offered the UCLA job on three other occasions, but always declined it. Whether Crum could have posted similar numbers as a head coach at UCLA as he did at Louisville, we’ll never know. However, the Bruins’ repeated failure to land Crum in the post-Wooden era could only have magnified Bruin fans’ frustration at the dearth of championships.


What about the players UCLA has recruited in the past 43 years? Centers Lew Alcindor (1966-67 to 1968-69; later known as Kareem Abdul-Jabbar) and Bill Walton (1971-72 to 1973-74) led the Bruins to five out of six possible national titles during their varsity playing careers, in an era of freshman ineligibility. That both of these all-time greats completed their respective senior seasons[2] is noteworthy, however, in terms of maintaining a dynasty. How many more NCAA titles would Michigan State have won, for example, if Magic Johnson hadn’t turned pro after his sophomore year?

UCLA has had some very good post-Wooden players stay four years – such as Ed O’Bannon, who led the Bruins to the 1995 title -- but many haven’t. And no Bruin player has had quite the impact of Alcindor or Walton. How good has UCLA’s on-court talent been over the past 44 years, relative to that of other schools?

The closest current program to the John Wooden-era Bruins, in my view, is Duke. Krzyzewski, with 39 years on the Blue Devils’ bench, gives Duke a similar iconic coaching figure to Wooden. Coach K has won fewer national titles (five) than has Wooden, but has the same number of Final Four appearances (12) as him. Whatever one thinks of this UCLA-Duke comparison, it is safe to say that bringing in Duke’s caliber of players would improve virtually any school’s chances of contending for national championships.

How has UCLA’s talent over the past 43 years compared to Duke’s? Using’s Recruiting Services Consensus Index (RSCI) Rankings (which go back to 1998-99), supplemented by my own personal stack of annual preseason college-basketball magazines[3] (going back to 1989-90), I devised a system to assign an overall yearly recruitment-quality score to UCLA and to Duke. I awarded three points for each Top 10 national recruit a school landed, two points for each recruit ranked 11-25, and one point for each recruit ranked 26-50. As an example, an entering class of two Top 10 players, a player ranked 11-25 and one ranked 26-50 would yield nine points. Results are shown in the three following graphs (which you can click to enlarge).

The upper-left graph shows UCLA’s year-to-year recruiting success, going back as far as I had data. The players who entered in the Bruins’ two best recruiting classes are listed in this graph. As is evident, there is a lot of year-to-year fluctuation in quality of recruiting classes (light-blue curve). These ups-and-downs are not necessarily unexpected, as bringing in a large class of top players one year may leave few, if any, available scholarships the next year. To glean more general or “smoothed” trends, I used loess regression (yellow line for UCLA).

The upper-right graph presents the same kind of curves for Duke. Finally, the bottom graph compares Duke’s and UCLA’s smoothed curves. Although the magnitude of the difference has varied, the Blue Devils have consistently out-recruited the Bruins over the past 30 years. UCLA’s instability in coaching may well have played a large role here.

Does UCLA’s post-Wooden ledger of six Final Four appearances and one national title represent a gross underperformance relative to what could reasonably be expected?

Only six schools have more Final Four appearances than UCLA in the post-Wooden era: North Carolina (14), Duke (13; one under Bill Foster in 1978 plus Krzyzewski’s 12), Kentucky (10), Kansas (9), Michigan State (9), and Louisville (7). Michigan is tied with UCLA at 6.[4] Though not making Final Fours at a Woodenesque level, Bruin teams have not exactly been doing badly over the past 44 years. Given UCLA’s six Final Four appearances post-Wooden, is the school’s one national title lower than would be expected? To address this question, I plotted for each school with at least one Final Four appearance from 1976-2019, its number of Final Four appearances (x-axis) against its number of national titles (y-axis).

Based on the past 44 years, the best-fit line in the above graph gives us the rough estimate that, for every three appearances in the Final Four, a team should win one national title. UCLA has made six appearances, so by this standard, the Bruins should have won two national titles. UCLA is therefore underperforming in this sense, but not egregiously so.

To what extent were Bruin fans judging Alford like UCLA’s immediate post-Wooden coaches?

In retrospect, many Bruin fans will probably find it ridiculous that Gene Bartow, with a 51-10 (.836) record and Final Four appearance at UCLA, felt the need to find a job elsewhere after two years in Westwood. Cunningham, with his 50-8 (.862) record, sincerely seemed to prefer administration over coaching, but with greater fan support at UCLA, he might have stuck around longer.

Fans’ harsh judgment of winning coaches who fail to replicate the success of legendary predecessors is not unique to Bruin hoops. Nebraska fired football coaches Frank Solich (58-19, .753, from 1998-2003) and Bo Pelini (67-27, .713, from 2008-2014), after they could not win national championships like former Cornhusker coaches Bob Devaney and Tom Osborne.

Alford’s winning percentage at UCLA was .663, well below Bartow’s and Cunningham’s. Yet, Alford received five and one-half years to prove himself. Alford had his critics among the fans throughout his Bruin tenure, but few presumably wanted him out after just two years. In that sense, Alford was not treated as harshly as Bartow and Cunningham.

A writer on one website covering UCLA sports argued strenuously that Bruin fans were not unreasonable in their judgment of Alford, but rather they simply felt the program was no longer “relevant” in national college basketball circles and a new coach would be needed to reinstate UCLA to the elite level.

In the post-Wooden era, UCLA has shown short bursts of national power (1995, 2006-2008) and, based on Final Four appearances, has still been one of the top programs in the country over the past 44 years. Perennial national contention as in the Wooden years seems a stretch at this point. Making the bursts of success more frequent and longer, and keeping the droughts shorter, is more plausible, but won’t be easy for new coach Cronin at UCLA.

With all the changes in the game over the past 40+ years – especially expansion of the tournament field and one-and-done players – does it even make sense to speak of college basketball dynasties?

The above analyses and discussion accept the premise that a contemporary college basketball program can succeed, if not at John Wooden’s level, at least at stringing together a few consecutive national championships. In fact, two schools have won back-to-back titles post-Wooden: Duke in 1990-91 and 1991-92, and Florida in 2005-06 and 2006-07. An additional two have won championships in two out of three seasons: Kentucky in 1995-96 and 1997-98 (with an overtime loss in the title game in between) and Villanova in 2015-16 and 2017-18.

So yes, stretches of three (or perhaps more) years of consistent national-championship contention are still achievable. These would probably satisfy most of today’s UCLA fans. However, changes in the game over the past four decades make such stretches highly unlikely, in my view. For most of John Wooden’s days at UCLA, there were around two dozen teams in the NCAA tournament field and only one team per conference could get in. In 1970-71, UCLA’s crosstown rival USC finished 24-2 (both losses to UCLA) and was perhaps the second-best team in the country, but did not get in. With many strong teams being excluded from the NCAA field back then, things were certainly easier for those who made the field.

As the field grew over the years to its current 68 schools, increasingly large numbers of teams from the power conferences were getting in. If teams get hot in March, it didn’t matter what their regular season record was – Exhibit A being the 2010-11 UConn men, who finished 9th in their conference and still won the national title. In the aforementioned listing of all-time best men's NCAA-championship teams, this UConn squad ranked 59th.

The second major change from Wooden’s time is, of course, the one-and-done phenomenon. Quite simply, with the best players nationally going to the NBA after one season, it is very difficult – if not impossible – for most programs to develop the continuity needed for a dynastic run. Kentucky in 2011-12 and Duke in 2014-15 won national titles with frosh-laden teams, but no team has done so since.. Lonzo Ball led UCLA to a 31-5 record and Sweet Sixteen appearance in 2016-17, but left after that one year.


In the months leading to Cronin's hiring, my impression was that UCLA fans would want an established head coach with a better NCAA postseason track record than Alford’s, someone who can produce a sustained run of national contention like Howland did, but without the team dynamics spiraling out of control. Cronin is an established head coach, but his NCAA postseason record is not better than Alford's. There's obviously no way to know at this point whether Cronin can lead the Bruins to national contention.

Someone with Final Four experience would have been especially coveted, but Cronin lacks this. One reported candidate for the Bruin job, Tennessee's Rick Barnes, took Texas to the Final Four in 2003, but he decided to stick with the Volunteers. In fact, UCLA has only once been able in the post-Wooden era to hire a coach who took a previous school to the Final Four. Gene Bartow. 

[1] The mini-banner pictured above, which listed all UCLA basketball championships to date, was given out to all fans at a Bruins game in the early 1980s. I was a student there at the time. The 1978 title was in women’s basketball, as denoted by the “W.”
[2] Walton might theoretically have been able to enter the NBA early under the 1971 Spencer Haywood ruling, but he did not.
[3] Mostly from the Sporting News, but also from Athlon, Lindy’s, and Street and Smith’s.
[4] Vacated appearances (e.g., Louisville in 2012 and 2013) are not removed from these totals.

Friday, January 25, 2019


Houston Rockets guard James Harden has set the sports world ablaze as a one-man scoring machine. Wednesday night in New York, Harden scored 61 points, extending his streak of scoring at least 30 points to 21 consecutive contests (game-by-game log). It is the fourth longest such streak in NBA history, with only Wilt Chamberlain recording longer streaks of scoring 30+ points (65, 31, and 25 games). The Rockets host Toronto tonight, as Harden seeks to keep lighting up the scoreboard.

Despite all the attention Harden has been getting, one can question the value of his streak for at least three reasons. First, prodigious scoring averages don't necessarily equate to championships. In fact, Wilt didn't start winning titles (in 1966-67 with the Sixers and 1971-72 with the Lakers) until his points per game came down and his shooting percentage went up (perhaps suggesting that he and his coaches became more selective in the shots he would take). Also, do you remember big scorer Carmelo Anthony leading the Nuggets or Knicks to the NBA title? Neither do I. Houston is 15-6 over the 21 games of Harden's 30+ streak (although only 5-5 over its last 10), so it would be hard to argue that the streak was hurting the team.

Second, has Harden really elevated his performance -- as the concept of a momentum-based hot hand would require -- or are his high-scoring nights more the product of shot volume than efficiency? With injuries to teammates Chris Paul and Clint Capela, Harden has been launching shots at an unprecedented rate for him. So far this season, Harden has attempted 23.9 shots per game from the floor. Previously, his highest single-season shots-per-game average was 20.1 (in 2017-18).

Looking at Harden's three-point attempts and success rate over the past 10 games (from most to least recent), one finds the following: 5-20 (.250), 6-13 (.462), 8-19 (.421), 5-19 (.263), 6-15 (.400), 1-17 (.059), 8-16 (.500), 6-16 (.375), 6-15 (.400), and 5-17 (.294). The statistics are mixed, but I would say volume is playing a large role in Harden's scoring.

Further pertaining to Harden's large role in the Rockets' offense, an 5-on-5 discussion asks "Can James Harden possibly keep this up?" This article discusses Harden's high rate of unassisted shots and high usage rate.

Third, will it hurt Houston over the long term to have Harden playing as great a number of minutes as he currently is? A FiveThirtyEight article asks "Will James Harden’s Hot Streak Burn Him Out?" This article documents, among other things, that Harden is tied for the lead league in minutes per game at 37; his effective field-goal percentage has declined in the fourth quarter of games over the past three seasons; and teams with one player carrying a heavy usage load tend not to do well in the playoffs.

The most recent Sports Illustrated magazine features a lengthy article on Harden and the Rockets. Houston coach Mike D'Antoni is quoted to the effect that he has no choice on playing Harden such heavy minutes. Given the Rockets' slow start to the season, "We gotta win games... We can't... come in eighth [in the Western Conference] and get knocked out in the first round."

Of course, Harden's scoring streak may just be an oddity, brought about by the absence of some of the Rockets' leading players. It will be interesting to see what happens when they come back!

Monday, December 24, 2018

Streaks in the City (4): Boston

For a large chunk of the 20th century, Boston had one professional sports team that, despite several close calls, could not win a championship. It had another that couldn't lose in the final round. Once the 21st century rolled around, the city saw a third team dominate its sport.

The first team being alluded to is the Red Sox, who famously went without a World Series championship from 1918-2004, losing four World Series -- all in seven games -- during the drought. There were additional pre-World Series heartbreaks for the BoSox, as well, namely losing the American League title by one game to the Yankees in 1949 after dropping games on the last two days of the season in the Bronx*; the blown 14-game lead in the 1978 AL East standings, leading to a one-game playoff for the division title, which went New York's way on a famous homer by "Bucky (Bleeping) Dent"; and a blown four-run lead to the Yankees in Game 7 of the 2003 AL Championship Series (season-by-season log).

The second team referenced in the opening paragraph is the Celtics. Led by legendary center Bill Russell, who was there the whole time, and an assortment of other NBA greats who were there either at the front or back end of the Celtics' dynasty, Boston won an amazing 11 NBA titles in the 13 seasons from 1956-57 to 1968-69. The following chart (on which you can click to enlarge) shows the championship years (those with a solid green heading) and the future Hall of Famers on each team.

The Celtics were 5-0 in NBA finals decided in seven games and 10-0 in Game 7's adding in pre-final playoff rounds during the 13-year span.** While winning eight straight NBA titles from 1958-59 to 1965-66, Boston claimed 17 straight playoff series wins.

The fortunes of the Red Sox and Celtics have reversed a bit in recent decades. Just this past fall, the Red Sox captured their fourth World Series title in 15 years (2004, 2007, 2013, and 2018). The 2018 BoSox won 108 games in the regular season, beat two 100+ win teams in the AL playoffs (Yankees and Astros), and dispatched the defending NL champion Dodgers in the World Series. In no playoff series this year did Boston lose more than one game.

Except for an eight-year stretch of sub-.500 seasons (1993-94 to 2000-01), the Celtics have been pretty good of late. They have made the playoffs in 14 of the previous 17 seasons and won the 2007-08 NBA title. However, the 2008 championship is the Celtics' only one in the past 32 years (season-by-season log).

As seen in the preceding paragraphs, the Celtics and Red Sox have won a bunch of titles. And we haven't even gotten to the NFL's New England Patriots (the third team alluded to in the opening paragraph)! The Pats have won five Super Bowls in the past 17 years (2001, 2003, 2004, 2014, 2016) and been in three others since 2000.

Despite all of New England's Super Bowl success, however, it may be the one that got away that sticks in fans' minds. In the 2007 season, the Patriots went 16-0, then added two playoff wins to reach the 2008 Super Bowl at 18-0. New England was thus in position to equal -- in concept, if not numerically -- the undefeated regular-season and playoff run of the 1972 Miami Dolphins.*** As is well-known to football fans, however, the New York Giants -- aided by the miracle "helmet catch" in the closing minutes -- pulled off a 17-14 stunner to thwart the Patriots' bid for immortality. A decade later, football observers are still dissecting the 2007 New England team.

Beyond Super Bowl metrics, the 2018 New England squad has continued the winning tradition and racked up some impressive regular-season streaks for the franchise. According to an article, "In securing their 10th consecutive division title, the Patriots have become the first team in NFL history to earn 10 straight playoff appearances" and "New England also secured its 16th consecutive season with a double-digit win total -- tying the 49ers' mark from 1983-1998" (season-by-season log).

The final Boston team among the big four North American pro sports is the NHL's Bruins. The B's (so dubbed for their logo) have won three Stanley Cups in what could be considered the modern era. The Bobby Orr and Phil Esposito-led Bruins captured Cups in 1969-70 and 1971-72. Boston has only hoisted the hardware once since then, 2010-11.

Orr, a defenseman whose career was limited by repeated injuries to his left knee, had few superiors when playing at his best. On the advanced statistic of combined offensive and defensive point shares, Orr led the NHL four years straight and five years out of six, between 1969-70 and 1974-75. As a frame of reference, Wayne Gretzky led in this statistic seven straight years from 1980-81 to 1986-87  (list of season leaders). Orr's teammate Esposito put together a streak of six straight years leading the NHL in goals scored (1969-70 to 1974-75).

In conclusion, the last 20 years or so have been a good time to be a Boston sports fan, largely driven by the Patriots and Red Sox. The Celtics' run from the mid-1950s to the end of the 1960s is unlikely to be duplicated in the foreseeable future, but even if the C's merely contend for a title or two in the coming years, rooting for Boston's teams will be even more fun.

*Prior to 1969, there were no divisions within the American and National Leagues, and no pre-World Series playoff rounds. The team that finished the regular season with the best record in the AL and the team that did likewise in the NL went directly to the World Series.

**Looking at all of the Celtics' deciding games during the 13-year span, the team was actually 11-0. Boston beat Cincinnati 3-2 in a best-of-five opening-round series in 1965-66.

***The NFL regular season was only 14 games long in 1972, so the Dolphins ended up 17-0 after the Super Bowl. The 2007 Patriots potentially could have finished 19-0.

Monday, May 28, 2018

Streaks in the City (3): Washington, DC

The Washington Capitals begin play in the Stanley Cup finals tonight, seeking to end a 26-year title drought in the nation's capital within the four major North American sports (football, baseball, basketball, and ice hockey). If the Capitals hoist the Cup, it will be their first time in their 44-year history. The Caps made the finals once before, 20 years ago in 1998, losing to Detroit.

The city's NFL team, which arrived in Washington in 1937 after a brief history in Boston, had a nice run in the 1980s and early 90s, winning the Super Bowl after the 1982, 1987, and 1991 seasons. The 1991 football championship (claimed in the 1992 Super Bowl) is the last major sports title won by a team from the nation's capital. Beyond 1991, Washington has made the NFL playoffs only six times, never winning more than one game in any postseason. Going way, way back, Washington captured pre-Super Bowl NFL titles in 1937 and 1942. These moments of triumph were followed a few years later by a 25-year string of playoff absences (1946-1970).

On the hardwood, the city's NBA team -- known as the Capital Bullets in 1973-74 after making a short move from Baltimore, the Washington Bullets (1974-1997)* and then Wizards (1997-on) -- has captured only one title, 40 years ago.

On the baseball diamond, Washington has been home to three franchises: the current team known as the Nationals (moved to DC in 2005, after playing from 1969-2004 as the Montreal Expos), the organization known since 1972 as the Texas Rangers (who had been the Washington Senators from 1961-1971), and the organization known since 1961 as the Minnesota Twins (previously another incarnation of the Washington Senators, from 1901-1960). So with three franchises, collectively playing roughly 85 seasons in the nation's capital, how many World Series titles does Washington have to show for it? That would be one. Led by legendary pitcher Walter Johnson, the 1924 Senators won it all. There is a famous quote long attached to Washington, DC, inspired by poor play early in the Senators' history: "First in war, first in peace, and last in the American League."

A Sports Illustrated article from last October summarizes the city's sports frustrations succinctly: "The sheer number of distressing losses is staggering, especially in recent years, when the Nationals, Wizards and Capitals have all been contenders, at least within their conferences. The Caps and Nats in particular have a penchant for heartbreak, especially in deciding games..."

To summarize, Washington, DC's baseball, basketball, football, and hockey teams have played a collective 250 seasons (roughly). During that time, these teams have combined for seven championships.**

As the SI article notes, Washington's professional sports futility is not quite as bad, if one includes soccer in the mix: "For some reason, D.C. United is immune to the curse. The MLS side has won four MLS Cups, though not since 2004..."

Also, at the college level, Georgetown University's men's basketball program under Coach John Thompson and star center (and current Georgetown coach) Patrick Ewing made three Final Fours in the four years from 1981-82 to 1984-85, with a national title in 1983-84.

Thus, although Washington sports fans have not seen major championships in recent decades, their teams are generally competitive.


*The renaming from Bullets to Wizards was prompted by two developments. One was the assassination of Israeli Prime Minister Yitzhak Rabin, a friend of Bullets' owner Abe Pollin, and the other was DC's high rate of gun-related violence at the time.

**Worth mentioning, at least as an historical footnote, are the barnstorming Washington Generals, variously described as the "perennial opponents" and "stooges" for the Harlem Globetrotters. As noted on the Generals' Wikipedia page, "While the Globetrotters play tricks and spectacular displays of skill for the crowd, the Generals appear to attempt to play a 'normal' game of basketball... not interfering in the Globetrotters' tricks." The Generals are estimated to have lost over 16,000 times to the Globetrotters and beaten them somewhere between three and six times.

Friday, May 11, 2018

Warriors' Explosiveness

ESPN The Magazine has an online article today on the Golden State Warriors' offensive explosiveness. Specifically, the article provides statistics on the Warriors' frequency of going on 10-0 and 15-0 runs, and examines whether there are distinguishing circumstances that seem to presage such runs and any effective strategies for opponents to short-circuit them (spoiler alert: time-outs don't seem to work).

Back in 2015-16, I examined the explosiveness of the Warriors (which I defined as scoring 18 or more points in six-minute intervals) and of the eight college teams seeded No. 1 or No. 2 in March Madness (defined as scoring 15 or more points in five-minute intervals).

One pattern I found for the Warriors in the final 6:00 of regulation play is that the further they were behind, the greater the offensive bursts they exhibited.

The college teams' explosiveness did not seem to predict NCAA-tourney success. Xavier was the most explosive team among the eight I studied by a good margin (13 explosions in its last 10 regular-season games, with no other team higher than nine). The Musketeers also had the fastest tempo (possessions per game) among the eight teams. Despite these seeming advantages, however, Xavier was eliminated in the second round.