Measuring NBA Players' Mood by Mining Athlete-Generated Content

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2015 48th Hawaii International Conference on System Sciences

                Measuring NBA Players’ Mood by Mining Athlete-Generated Content

                              Chenyan Xu                                                                    Yang Yu
                   The Richard Stockton College of New Jersey                                   Rochester Institute of Technology
                        chenyan.xu@stockton.edu                                                      yyu@saunders.rit.edu

                                   Abstract                                         were using Twitter in the 2012-13 NBA season
           Online athlete-generated content in social media                         which represented an approximate of 78.4% of the
       has high potential to become the information source                          total; they posted 91,659 tweets throughout the
       for both team managers and coaches to discern                                season. With the unique features of Twitter and its
       players’ mood status and shaky performance before                            large user base, NBA players capitalize on this
       games. In the existing literature, either in psychology                      emerging technology to communicate with fans,
       or sport analytics, there is a stream of research that                       journalists, peers, friends and other followers. They
       investigated the relationship between athletes’ mood                         actively voice their opinions, express thoughts and
       and the individual sport performance; however, few                           show feelings through short, direct messages of 140
       of them discussed the causality from the social media                        characters or less on Twitter.
       perspective. In this study, we look deep into the                                The following examples unfold several Twitter
       Athlete-generated content (AGC) and aim to provide                           landmarks in the NBA, which we believe could help
       a more comprehensive framework to sport operators                            readers gain a general idea of how NBA players use
       that incorporates players’ social media content into                         Twitter. In 2011, when the second longest NBA
       their administrative decision-making process. We                             lockout in history came to an end, a lot of players
       obtained a unique and extensive dataset of AGC for                           tweeted their excitement that the new season is
       active NBA players (in the 2012-13 season) from                              finally coming. In 2013, NBA center Jason Collins
       Twitter and apply sentiment analysis technique to                            announced that he is a gay, making him the first
       measure the general mood polarity of a player. The                           openly gay player in the league. He then received
       general mood was then incorporated into                                      tremendous support from other players on Twitter. In
       econometrics models to examine its effect on players’                        April 2014, TMZ released an audio clip that records
       individual game performance. The results suggest                             Los Angeles Clippers owner Donald Sterling’s racist
       that the mood of NBA player has significant effect on                        comment on minorities. Shortly after that, he was
       driving sport performance. This paper explores the                           severely criticized by NBA players on Twitter who
       possibility of using social media data to measure                            expressed their shocking, disappointment and anger
       athletes’ mood and predicting the sport performance.                         towards Sterling and called for an immediate
                                                                                    investigation and action on him. It is worth noting
       1. Introduction                                                              that players’ use of Twitter is not always positive and
                                                                                    it also produces unpredictable problems for the
                                                                                    league, teams and players themselves. In 2009,
           The past decade has seen tremendous shifts in                            Milwaukee Bucks forward Charlie Villanueva posted
       popularity among different browsers, operating                               a tweet during halftime of a home game against
       systems and social networking site (SNSs),                                   Boston Celtics. It is worth noting that this act not
       especially, SNSs. Take Twitter as an example. Since
                                                                                    only costs him to receive severe criticism from the
       its inception in 2006, Twitter has grown rapidly,                            media for not paying attention during the game but
       gaining worldwide popularity. As of June 2014, there                         also leads the league to issue a policy that prevents
       are 255 million avid users on Twitter who post an                            team players, coaches and official from using Twitter
       average of 500 million Tweets per day 1 . While                              and other SNSs during games. In June 2009,
       Twitter has become an important component of
                                                                                    Minnesota Timberwolves forward Kevin Love
       people’s lives, it is not an exception for professional
                                                                                    disclosed on Twitter that header coach Kevin McHale
       athletes such as the players of the National Basketball
                                                                                    would not return in the new season and he was sad
       Association (NBA). According to the information we
                                                                                    about his leaving. While for the first time, such
       gleaned from Tweeting-Athletes.com and Basketball-
                                                                                    breaking news came before any conventional media
       Reference.com, there were 353 active players who
                                                                                    reported it, this tweet also put Love in an awkward
                                                                                    position for making McHale’s unofficially-revealed
       1
           Retrieved June 10, 2014, from https://about.twitter.com/company          decision public. Worse, in 2012, San Antonio Spurs

1530-1605/15 $31.00 © 2015 IEEE                                              1706
DOI 10.1109/HICSS.2015.205
swingman Stephen Jackson issued a threatening                     positive WOM could also contribute to increased
Twitter to another player and was later fined $25,000.            stock price. With this line of reasoning, sentiment
    With the widespread use of Twitter among NBA                  analysis, a text mining technique that distills moods
players, an interesting question then arises: how the             (e.g., positive vs. negative) underlying textual data,
players generated messages impacts games?                         was used to analyze tweets. It was found that the
Actually, NBA teams have already recognized the                   extent to which the overall sentiment of the tweets
market value of social media; all 30 NBA teams have               with regard to a movie is positive (indicating positive
created their Twitter accounts and use Twitter as one             WOM) has a large effect on the sales of the movie
of important marketing and communication channels.                [7]. Taking a step further, other academic works
However, we also noticed that just like some non-                 found that the overall sentiment of the tweets about
sport organizations which frown upon employees’                   IT products is associated with the stock prices of the
use of SNSs for private purposes, the NBA league                  companies in question [8].
and teams seem to be less friendly on players’ use of                 Motivated by this stream of works, echoing the
Twitter with a concern that it would distract them                prevalence of Twitter usage among NBA players, in
from winning games[1]. For example, in 2009, the                  this study, we presents a demonstration that uses the
league has enacted a policy stating that coaches and              sentiment analysis to gauge players’ moods from
players are not allowed to use SNSs from 45 minutes               their tweets and shows that the distilled moods
before game time until after post-game interviews are             (positive vs. negative) could be used to predict
completed. Moreover, teams such as Miami Heat,                    player’s individual game performance. The rest of the
Toronto Raptors, Milwaukee Bucks and Los Angeles                  paper proceeds as follows. In the next section, we
Clippers have expanded the ban on SNSs to “team                   review the previous related studies on moods and
times” including team practices and team meetings                 performance. Next we propose the framework to
[2].                                                              analyze AGC in the NBA scenario and illustrate the
    This paper proposes that in addition to Twitter’s             process of using this framework on athlete mood
business value to organizations, NBA teams also can               detection and sports decision making. We conclude
benefit from the tweets posted and made public by                 the paper by discussing the limitation and identifying
their players. When governments could listen to,                  areas for future research.
analyze and understand citizen opinions voiced via
information communication technologies such as                    2. Mood and Sport Performance
SMS messages and websites, and absorb the
feedback into administrative decision-making process
[3], operators of NBA teams such as coaching staffs                   In the sport field, there is a consensus that
and the general managers could use Twitter to                     athletes’ performance can be fluctuated with their
discern players’ status when they are not on the                  varied moods. This phenomenon has its root in a
basketball court, particularly their moods, and to use            more generic moods-performance relationship well
the information that is otherwise difficult to obtain to          established in the psychology field. Research[9]
predict their performance in the upcoming games. To               found that moods can affect a range of processes
this end, text mining and sentiment analysis will be              when individuals engage in different tasks. These
applied on AGC to extract hidden intelligence from                processes include perception, reasoning, memory and
unstructured textual content, which allows teams to               behavior, all of which are significant antecedents of
capture players’ moods reflected by their words.                  performance. In particular, positive moods such as
    Tweets have become a source of new intelligence.              arousal and pleasure contribute to greater helping
The locations, timing and content of tweets are                   behaviors, enhanced creativity, improved decision
informative in predicting future events [4, 5]. Twitter           making and better team collaboration [10-12]. All
has been demonstrated to explain, detect and predict              these outcomes remain critical for basketball players.
a number of phenomenon, including disease                         For example, we can expect that affected by good
outbreaks,     election    results,    macroeconomic              mood, a swing man could be more active in covering
processes, natural phenomena, product sales and                   up his teammates when they accidently turn the ball
financial markets [6]. For example, tweets posted by              over or when they mistakenly leave an open shot
customers are thought of as a new form of word-of-                opportunity to opponents; a point guard with positive
mouth (WOM). WOM plays a critical role in shaping                 mood could be more imaginative in passing the ball
one’s decision to purchase a product. Affected by                 to penetrates defense that is otherwise impossible;
positive WOM, people are more likely to purchase a                when doubled, a center with positive mood could
product. Furthermore, given the close association                 make better judgment between shooting himself and
between product sales and the market value of a firm,             passing the ball to teammates. Observing the effects

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of athletes’ moods on performance, researchers                   Wizards. Effectiveness and efficiency aside, such
explored and discussed the mechanisms through                    interventions cannot succeed without acquiring
which such effects occur. Among them, Lazarus[13]                players’ moods in the first place. As noted earlier,
argued that in a competitive sport, an athlete must              NBA players made extensive use of Twitter, tweeting
closely anticipate and observe an opponent’s actions             their opinions, thoughts and feelings. This stream of
during interactive plays so can s/he instinctively               tweets represents an enormous, unfiltered opportunity
know what to do next as a response. While good                   to characterize players’ moods before games. Similar
moods help the athlete stay focused and vigilant, bad            approach that uses tweets to monitor the moods of a
moods could be a major source of the interferences               segment of Twitter users was practiced on the
that drive away their attentions from completing                 participants and journalists involved in the 2011
these perceptual and cognitive tasks. One might                  Egyptian Revolution [16] and, more frequently,
further wonder why negative moods can shift an                   existing and potential customers of a particular
athlete’s required focus away. According to                      product [7] or a company [8].
Totterdell[14], negative moods take extra efforts to                 The mood detection is important to either team or
repair and consume attentional resources needed by               manager, however, acquiring and using players’
the cognitive processing of a sport. As a result, an             moods from tweets is not straightforward because
athlete stays less focused in the game and his/her               tweets take the form of unstructured text and too
performance is jeopardized by the bad moods. In                  much noise is hiding in them. We need tools to
addition, Totterdell suggests that positive or negative          analyze a sea of textual data in order to distill the
moods lead to different cognitive processing styles,             hidden intelligence. Figure 1 outlines a framework
and the cognitive styles incurred by positive moods              we recommend to team operators that incorporates
are more conducive to achieving good performance                 players’ tweets into their administrative decision-
in competitive sports. For example, positive moods               making process. It supports listening to and analyzing
stimulate greater efforts, motivation and persistency.           the tweets made public by NBA players which could
It is worth noting that latest research[15] reported             help the operators of NBA teams know players’
that certain negative moods could increase a type of             mental status (e.g., negative moods) and detect
disruptive concentration, namely self-focus. Self-               players’ potential sport performance ahead, and then
focus occurs when one spends too much attention to               introduce necessary interventions. In this framework,
do the right motion that disrupts the natural or                 NBA players post tweets as reactions to a number of
automatic ability to perform. For example, in                    things such as feelings about a game, thoughts about
basketball, self-focus often kicks in when a player              coaches’ decisions, or more frequently life
makes free-throw mechanically going through the                  encounters. At the core of our recommendation is an
sequential steps of making the best free-throw in                emerging text-mining technique–sentiment analysis–
mind.                                                            that could be employed to sift through players’ tweets
                                                                 and identify players’ moods before games. The
3. Framework of Mood Detect from AGC                             results are then summarized as a report which is later
                                                                 presented to the operation staff of NBA teams. Given
    In this study, we put the framework under the                the robust mood-performance association in the
basketball scenario. NBA teams have long                         context of basketball (which we will demonstrate
recognized the importance and necessity of adjusting             later), team operators could draw upon necessary
player’s moods before games. They take various                   approaches that are being practiced to smooth
approaches to accomplish this goal. For example,                 players’ negative moods or evoke positive moods.
after Donald Sterling’s scandal broke out, there was a               The distilled moods from players’ tweets are not
voice that fans and the players of Clippers should               free of bias, which could be attributed to a number of
boycott the rest games. Feeling that his players are             factors. First, the bias can arise from self-selection.
inundated with the disturbance, the Los Angeles                  Certain players’ might simply post what they want to
Clippers coach Doc Rivers cancelled the upcoming                 be seen in Twitter, promoting a good image. While
practice and took one day off to give them a breathe.            we cannot rule out the possibility of self-selection,
During the same period of time, the Indiana Pacer’s              we believe its confounding effect is minimum. Past
center Roy Hibbert was struggling in his playoff                 SNS research reported that individuals use SNSs
journey. To help him relax and regain confidence, his            primarily for showing affection and expressing
teammate Paul George invited Roy to a fishing trip,              themselves [17]; parallel to that, research in the sport
which was paid off by Roy’s 28 points and nine                   domain[18] confirmed that the same motivations
rebounds in the next game, as well as the Pacer’s                continue to hold when athletes use social media.
victory over their opponents – the Washington                    Specifically, Twitter ensures athletes that their

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undiluted perspective on events and subjects can be                   In this study, we built two datasets, namely the
heard immediately. In fact, the spontaneous use of                AGC dataset and the sport performance dataset. To
Twitter among athletes brings about an issue that                 build AGC, we refer to Tweeting-Athletes.com
they barely consider the consequences of the posted               which summarizes all NBA players’ twitter accounts.
messages[19]. The problem is so serious that the                  There were 353 active players in the 2012-13 NBA
ESPN experts suggested that “maybe next time he’ll                season. Thus, AGC contains the tweets posted by
think before he Tweets”[19]. On the other hand,                   these active NBA players during this time period. For
organizations such as teams and leagues have to                   each tweet, content aside, the dataset also includes
institute regulations to curb the “lack of thought”               descriptive attributes such as timestamp when the
issue (recall NBA’s and certain NBA teams’                        tweet was posted. AGC reveals that almost all active
restrictive policies on players’ social media use                 players in the league own his twitter account. They
mentioned earlier). In summary, with all the                      posted a total of 91,659 tweets in the 2012-13
anecdotal, practical and academic facts taken                     season 2, there are 51,847 original posts and 47,468
together, tweets record players’ feelings, opinions               are written in English. Notice that not every player is
and thoughts that self-revealed with a spontaneous                an avid user of Twitter; actually 87 of 353 posted less
intention. While Twitter can truthfully and accurately            than 100 tweets or never posted even one. The
record consumers’ moods, likewise, it can be a                    dataset also identifies some noticeable “activists” of
credible channel to discern players’ moods and                    Twitter. We consider those players posted at least
Tweets can be also used to capture their status before            100 tweets as active users, who account for 75.3% of
games to a great extent. Second, the procedure of                 the total.
obtaining players’ moods from large scale of textual                  We retrieved game by game data in the 2012-13
data is another potential source of bias. The virtues of          season and player data from basketball-reference.com
sentiment analysis, however, can compensate such                  to build the sport performance dataset. The
bias. As noted earlier, this emerging text-mining                 information of a game is concatenated with the
technique has demonstrated robust validity in                     information of a player who plays the game, which
gauging customers’ moods in Twitter and the                       appears as one record in the dataset. The extracted
quantified moods have been used in predicting a                   game information includes game date, game type,
number of future events. The next section presents a              home/away, opponent and win/loss (score). The
demonstration that details the process of applying                player information includes age (on the day of the
sentiment analysis to obtain NBA players’ moods                   played game), games started, minutes played, filed
underlying their tweets and further shows how the                 goals (percentage), 3-point field goals (percentage),
acquired moods are associated with their                          free throws (percentage) and Plus/minus (+/-).
performance in the upcoming games. Obviously, the                     In this study, we select Plus/minus (adjusted) as
results of this study could be summarized into a                  the individual sport performance measure 3 .
report delivered to team operators for further actions.           Plus/minus is a metric that assesses how a team
                                                                  performs with a certain player on/off the court and
                                                                  calculates the overall impact that player has on team
                                                                  success. Plus/minus began as a hockey metric, and
                                                                  has been kept as an official NHL (National Hockey
                                                                  League) statistic since 1968. Around 2003, Roland
                                                                  Beech introduced this concept to NBA. A few years
                                                                  later, the league made +/- part of its official box score
                                                                  statistics. This metric is much more meaningful in
      Figure 1. A conceptual framework of
                                                                  basketball than it is in hockey, even though it took
    athlete mood detection based on AGC
                                                                  much longer for the NBA to begin using it. The more
                   analysis
                                                                  scoring there is in a game, the more useful this
                                                                  statistic becomes. Plus/minus is a useful means to
4. An Illustration to NBA 2012-13 Season                          determine a player's value to the affiliated team
                                                                  because it takes into account everything a player does
    The purposes of demonstration are two-fold. First,            on the basketball floor, even things not reflected by
it details a process of applying sentiment analysis on            existing NBA statistics. For example, when a player
AGC to identify athletes’ moods before game.
Second, it tests whether the identified moods of a
                                                                  2
player are associated with individual sport                         October 30, 2012 – April 17, 2013 April 20 – June 3, 2013
performance in an upcoming game.                                  (Playoffs), June 6 – 20, 2013 (Finals)
                                                                  3
                                                                    http://www.82games.com/barzilai2.htm

                                                           1709
is on the floor and his team scores 7.5 points more              results of sentiment analysis applied to collected
than its opponent, his + value is +7.5; when this                players’ tweets.
player is not in the game, and his team scores 3.3
points less than the opponent, his – value is -3.3;
taken together, the +/- of the player is +10.8. We also
normalized this performance indicator in testing the
model because we are interested in players’ changed                               Table 1. List of Emoticons
performance instead of the absolute values.                       Emoticons mapped to :)                Emoticons mapped to :(
    In order to represent all the tweets accurately, we           :)                                    :(
                                                                  :-)                                   :-(
started out to preprocess the contents from which                 :)                                    :(
players’ moods would be obtained. We filtered out                 :-p or :-q                            :-e
those pure retweets, and information-oriented tweets              ^_^ or =^_^=                          :-( )
that contain any URL links. We also removed non-                  (^0^) or ^o^                          X-<
English tweets. Given the fact that Twitter is replete            =)                                    :[
                                                                  :-D or :D or =D                       >:O or >:-O or >:o or >:-o
with non-standard English, we applied a data
                                                                  Note: Each word in AFINN list has a score from -5 to +5 to
cleansing mechanism to deal with the issue. We                    describe the sentiment polarity and degree. Here, we mapped all
corrected these misspelled words with minimum                     these emoticons to either - or / and extent the AFFIN list by
Hamming distance, an automatic error correction                   assigning -2 to / and +2 to -.
algorithm. The non-standard English scenario could
also originate from repeating letters. For example,                    Table 2. Examples of players’ tweets with
some arbitrary number of letters would be shown as                            different mood polarities
“Awwwwful”, “Awfuuuul” and “Ruuuude”. To deal
                                                                                                                                 Mood
with this issue, we replaced any letter occurring more             Player              Tweet            Time       AFINN*       Polarity
than two times with two consecutive occurrences of                Al            Nice Win for us            13-          5        Positive
the same letter and then subsequently corrected as                Horford       on the road vs         Nov-12
misspelled words.                                                 Position:     Portland. Much         6:13:18
    To detect the sentiment polarity of each tweet                Forward       better effort             AM
(i.e., a player’s mood hidden behind each tweet), we              Team:         tonite. Go
used AFINN sentiment lexicons, associated with a                  Atlanta       Hawks!
                                                                  Hawks         Shaq! RT                   13-             1     Positive
manually built emoticons list. AFINN is a sentiment
lexicon containing English words manually labeled                               @owen_then:            Nov-12
                                                                                @Al_Horford            6:53:11
by Finn Arup Nielsen. Words were rated between
                                                                                who's your                AM
minus five (negative) and plus five (positive); the                             alltime favorite
larger the number, the more positive the sentiment of                           center??
the word is. While developed based on the Affective                             Happy birthday!            13-             2     Positive
Norms for English Words lexicon (ANEW) proposed                                 RT @Md813:             Nov-12
by Bradley and Lang, AFINN is more focused on the                               @Al_Horford            8:33:34
language used in microblogging platforms because its                            Can ur #1 fan get         AM
word list includes slangs, obscene words, acronyms                              a birthday
                                                                                tweet??? :)
and web jargons which are prevalent in the Internet
                                                                                Thanks. I really           14-             4     Positive
context. We wrote an application with R that
                                                                                enjoy having my        Nov-12
automatically extracts features related to the AFINN
                                                                                own segment! RT        4:55:42
lexicon from a given tweet, and then calculates an                              @KimberMcCart:             PM
AFINN score of tweet by summing the ratings of the                              Love the
positive and negative words that match the lexicon.                             @Al_Horford
The computed AFINN score reflects the mood of a                                 show on
player underlying the tweet. Moreover, tweets are                               Tuesdays with
characterized by various emoticons that can express                             @kingcfb and
                                                                                @RealMattlanta
moods. For example, either “:)” or “:-)” expresses
                                                                  Jarrett       What's good!               16-             4     Positive
positive mood, and “:(” expresses negative mood. We
                                                                  Jack          Here in                Nov-12
also considered the emoticons in our extended list by             Position:     Sacramento,            4:37:43
mapping them to either “-”or “/”. The full list of                Guard         getting ready for          PM
emoticons could be found in Table 1. The examples                 Team:         the game tonite.
presented in Table 2 provides a snapshot view of the              Cleveland     Go Hawks!

                                                          1710
Cavaliers   How u gonna fire         28-          -1   Negative          player’s mood is. Moreover, to enable the
            the owner?           Nov-12                                  comparison of moods among different players, we
                                 8:25:12                                 normalized the daily AFINN scores by using the
                                    AM                                   mean and standard deviation of all his seasonal
                                                                         available records (Table 3.).
Steve       @Naimthestar             28-          -2   Negative              To test the mood-and-performance relationship,
Nash        haha u sound         Nov-12                                  we developed a model that regresses a player’s mood
Position:   really upset over    8:39:51                                 before a game on his performance of the upcoming
Guard       there sir and is        AM
Team:       this a bad time to                                           game. Figure 2 describes the details of the model.
Los         bring up that                                                Consistent with prior psychology and sport literature,
Angeles     game on                                                      it was found that mood has a positive effect on player
Lakers      thanksgiving                                                 performance (β = 0.014, p < 0.05) (Table 4). This
Spencer     nomoreyears!             06-          -1   Negative          confirms that a player’s mood discerned by his tweets
Hawes                            Nov-12                                  posted prior to game is positively associated with his
Position:                        8:19:45                                 performance in the upcoming game. Such finding is
Center                               PM                                  essential because it justifies the value of applying
Team:
Cleveland                                                                sentiment analysis to examine NBA players’ moods.
Cavaliers   Philly should be         06-          -3   Negative          Team operators could draw upon sentiment analysis
            better than this.    Nov-12                                  to discern players’ moods by examining their tweets.
            Damn shame.          8:43:52                                 Given the association between players’ moods and
                                     PM                                  their potential performance, coaching staff could turn
                                                                         to necessary approaches to smooth players’ negative
            No hope. No              07-          -3   Negative          moods or arouse positive moods. In this sense, the
            change. Nobama.      Nov-12                                  use of Twitter among NBA players help team
                                 6:58:26                                 operators stay connected with the status of these
                                     PM                                  players. We took a step further by drilling across
Note:                                                                    three positions - center, forward and guard. This
* The AFINN score reflects the extent to which a player’s mood           additional analysis provides a better understanding of
hidden in a tweet is positive. The larger the AFINN score, the           the mood-and-performance relationship across three
more positive the sentiment of a tweet, and vice versa.                  important positions in basketball. It was found that
                                                                         moods suggested by players’ tweets continue to
        Recall that the second goal of the study is to test
                                                                         affect performance for centers (β = 0.024, p < 0.1)
    the association between the identified moods of a
                                                                         and forwards (β = 0.031, p < 0.05) whereas such
    player and his performance in an upcoming game. A
                                                                         effect does not hold for guards. While it is beyond the
    player might post several tweets before game. Before
                                                                         scope of this study to discuss why the effect of
    we simply aggregate the AFINN scores of the tweets
                                                                         moods varies by player positions, such analysis
    (posted prior to a game) to obtain a players’ moods
                                                                         shows team operators the customization aspect of
    before game, it is important to deal with the
                                                                         sentiment      analysis,    demonstrating       various
    timestamp issue. Typically, an NBA game start at
                                                                         applications of the technique to discern the status of
    8:00 PM of the game day. Also due to the media
                                                                         players with different traits such as age, salary and
    policy issued by the league that prevents team
                                                                         nationalities.
    players, coaches and officials from using Twitter and
    other SNSs from 45 minutes before game time until
                                                                                =  +        +                        Eq(1)
    after the post-game interviews are finished, we then
    selected 7:00 PM (in the game day) as the cutoff time                      Model Description
    to define “before game”. This is to say that, for a                         represents the performance of player i for a game at
    particular game played by a player, his tweets posted                  day t.
    dating back from 7:00 PM in the game day until 7:00                          represents the mood of a player i on the day t.
    PM one day before will be used to discern his moods                           represents the player-specific effect that capture the
    before the game. The AFINN scores of the tweets                        idiosyncratic characteristics associated with each player.
    submitted during this time frame are summed. The                                  Figure 2. Regression model
    total score represents a player’s mood before game.
    The higher the aggregated score, the more positive a                     On the foundation of the base model, we extend
                                                                         the model by controlling the position of players and
                                                                         investigate how the patterns shift among different
                                                                         positions.

                                                                  1711
 =  +    +   +  Eq.(2)                                   * p
in the context of Twitter has evolved and is capable                  [3] Evangelopoulos, N., and Visinescu, L., "Text-Mining the Voice
of distilling customers’ moods and predicting product                 of the People", Commun. ACM, 55(2), 2012, pp. 62-69.
                                                                      [4] Gerber, M.S., "Predicting Crime Using Twitter and Kernel
sales and firm value, the demonstration opens the                     Density Estimation", Decision Support Systems, 61(0), 2014, pp.
door of such analysis to the league and NBA teams                     115-125.
which have not exploited the huge amount of players’                  [5] Thelwall, M., Buckley, K., and Paltoglou, G., "Sentiment in
tweets, except for issuing restrictions on the Twitter                Twitter Events", Journal of the American Society for Information
                                                                      Science and Technology, 62(2), 2011, pp. 406-418.
usage. It is then up to the stakeholders of NBA teams                 [6] Kalampokis, E., "Understanding the Predictive Power of Social
to customize sentiment analysis for various purposes                  Media", Internet Research, 23(5), 2013, pp. 544 - 559.
(as shown in the additional analysis of the case study)               [7] Rui, H., Liu, Y., and Whinston, A., "Whose and What Chatter
and harness the findings of sentiment analysis to                     Matters? The Effect of Tweets on Movie Sales", Decision Support
                                                                      Systems, 55(4), 2013, pp. 863-870.
manage players. While the value of sport analytics is                 [8] Yu, Y., Duan, W., and Cao, Q., "The Impact of Social and
well-recognized among the “big four” professional                     Conventional Media on Firm Equity Value: A Sentiment Analysis
sport leagues, text-mining, particularly sentiment                    Approach", Decision Support Systems, 55(4), 2013, pp. 919-926.
analysis, empowers sport analytics by allowing for                    [9] Parkinson, B., Totterdell, P., Briner, R.B., and Reynolds, S.,
                                                                      Changing Moods: The Psychology of Mood and Mood Regulation,
processing unstructured text data such as tweets.                     Addison Wesley Longman London, 1996.
                                                                      [10] Baron, R.A., "Environmentally Induced Positive Affect: Its
6. Limitations and future study                                       Impact on Self- Efficacy, Task Performance, Negotiation, and
                                                                      Conflict1", Journal of Applied Social Psychology, 20(5), 1990, pp.
                                                                      368-384.
    While the sentiment analysis approach and the                     [11] Forgas, J.P., "On Feeling Good and Getting Your Way: Mood
proposed framework appear to provide an avenue to                     Effects on Negotiator Cognition and Bargaining Strategies",
detect NBA players’ mood status and foresee their                     Journal of personality and social psychology, 74(3), 1998, pp. 565.
                                                                      [12] Staw, B.M., and Barsade, S.G., "Affect and Managerial
game performance, this exploratory study still has                    Performance: A Test of the Sadder-but-Wiser Vs. Happier-and-
several limitations. First, in this study, only                       Smarter Hypotheses", Administrative Science Quarterly, 1993, pp.
individual mood was considered. In basketball, a                      304-331.
team activity, it is reasonable to expect one’s mood                  [13] Lazarus, R.S., "How Emotions Influence Performance in
                                                                      Competitive Sports", The Sport Psychologist, 2000,
or performance could be affected by others’ mood.                     [14] Totterdell, P., "Catching Moods and Hitting Runs: Mood
Second, only the position factor was incorporated in                  Linkage and Subjective Performance in Professional Sport
the model. In fact, there are other factors that could                Teams", Journal of Applied Psychology, 85(6), 2000, pp. 848.
affect players’ game performance, for example,                        [15] Goldman, M., and Rao, J.M., "Effort Vs. Concentration: The
                                                                      Asymmetric Impact of Pressure on Nba Performance", Book Effort
opposing team’s capability, game importance (e.g.,                    Vs. Concentration: The Asymmetric Impact of Pressure on Nba
playoff games or games for play off qualification).                   Performance, 2012, pp. 1-10.
Following this line of reasoning, we believe the                      [16] Choudhary, A., Hendrix, W., Lee, K., Palsetia, D., and Liao,
absence of other control variables is another major                   W.-K., "Social Media Evolution of the Egyptian Revolution",
                                                                      Commun. ACM, 55(5), 2012, pp. 74-80.
limitation. Third, data in only one season was tested                 [17] Xu, C., Ryan, S., Prybutok, V., and Wen, C., "It Is Not for
in this study, and this could be a potential source of                Fun: An Examination of Social Network Site Usage", Information
bias.                                                                 & Management, 49(5), 2012, pp. 210-217.
    Nevertheless, the study represents one of the early               [18] Hutchins, B., "The Acceleration of Media Sport Culture:
                                                                      Twitter, Telepresence and Online Messaging", Information,
efforts from the IS field to extend the reach of                      Communication & Society, 14(2), 2011, pp. 237-257.
sentiment analysis to the sports domain. Future                       [19] Walsh, D., "All a Twitter: Social Networking, College
research could be conducted using the proposed                        Athletes, and the First Amendment", Wm. & Mary Bill Rts. J.,
framework here, for example, taking more specific                     20(2011, pp. 619.
sport domain knowledge into account by examining
the effects of other factors and how these factors
interact with the mood factor. Another area is to
focus on specific emotion such as joy, excitement,
fear and frustration, and examine their individual
effects on sport performance.

6. References
[1] Friedman, D.J., "Social Media in Sports: Can Professional
Sports League Commissioners Punish 'twackle Dummies'?", Book
Social Media in Sports: Can Professional Sports League
Commissioners Punish'twackle Dummies'?, 2012, pp. 74.
[2]http://sports.espn.go.com/nba/news/story?id=4520907, accessed
May 16, 2014.

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