comparing cousins – a harmonized analysis of racket sport set scores using racketlon world tour...
TRANSCRIPT
Comparing Cousins
– A Harmonized Analysis of Racket
Sport Set Scores using Racketlon
World Tour Results
MARKUS BORG, LUND UNIVERSITY
RICHARD BOREHAM, ERA RANKINGS OFFICER
Dr. Markus Borg
MSc Computer Science & Eng.
PhD Software Engineering
• Empirical research
• Machine learning
President of Malmö Racketlon
Swedish Racketlon Federation
Board Member
Richard Boreham
BA Mathematics
Social Researcher
• Statistical analysis
• Programming
• Data Management
ERA Rankings Officer
Racketlon saves the day!
Outline
• Racket Sports on Equal Terms – Racketlon!
• English Racketlon Association’s New Ranking System
• Statististal Analysis
– RQ1. Win big?
– RQ2. Tighter sets?
– RQ3. Cross-sport Rating Correlation
• Wrap-up and Implications for Racketlon
Racket Sports on Equal Terms
– Racketlon!
Gist of the Sport
• Who is the best overall racket sports
athlete?
• Using an equal scoring system in the
four racket sports
– Sum up individual set scores
instead of sets
– Every single point important!
• ”Damage control” in weaker sports
fundamental
Rules of Racketlon
• Scoring system (since 1994)
– Play four sets to 21 using point-a-rally scoring
» Margin of two points
– Sum up individual set scores to determine the winner
– Match finishes early when enough points have been played
• Serves
– Alternating two severs each (right, left)
– First and second serve in tennis
Example Match Scores
• Tight game, recovering from table tennis
• Winning only one set, but still the match
Racketlon Player Profiles
• Flat profile
– Allround in the individual sports
• Skewed profile
– Specialist in one or two particular sports
– Weak in one of the sports
FIR - Federation International de Racketlon
• 2001 - First international tournament in Gothenburg, Sweden
• 2002 - International Racketlon Federation (IRF) founded
• 2005 – Name change to Federation Internationale de Racketlon
(World tour growing and maturing…)
• World Tour 2015 – 16 events in 14 countries
– 13 International World Tour events
– 3 Super World Tour events
• World/European Championships
ERA and the New Ranking
System
Role of Rankings
• Always a challenge – always debatable
– Important role in tournament organization
– Difficult in racketlon due to players’ profiles
• Two basic approaches:
i) POINTS-BASED: Collect points on tour
– Pros: Encourages players to compete
– Cons: Highly active players overranked
ii) RATINGS-BASED: Altered after every match
– Pros: Better reflects player strength
– Cons: Players might avoid tournaments to freeze
ranking, Players in lower divisions that never loose
overranked
FIR World Ranking
• Players earn points when entering FIR tournaments
• The player’s 10 best tournaments in last 24 months count
English Racketlon Association
• 2002 - First UK Tournament
• 2003 - Joined FIR (IRF)
• 2008 - ERA created
• 2014 - 14 ERA tour events, plus Welsh Open and World
Championships
• Now - Around 150 active players
Old Ranking System
• Points-based
– Different points for A, B, C classes
– Winner of B got less than last place in A
– Biased towards regular entrants
• From 2012 average of 8 best tournaments
– Winner of B gets more than last place in A
– Winner of larger class entry gets more points
– Average to minimise bias to regular entrants
New Ranking System
• Rating-based
– Based on individual matches, not tournament placing
– Winner’s rating goes up, loser’s goes down
» How much depends on difference in rating
– Ratings recalculated after each match (post tournament)
» Roughly 10,000 - 20,000
• ”Contagious” ratings spread to all FIR players
New Ranking System – Cont.
• Individual Sport Ratings
– Independent of overall rating
– Similar maths to overall rating
• Example:
– Peter Sákovics (Sep 2014) - Total rating 17,340 (A2)
» TT – 16,294 (A4)
» BD – 17,039 (A2)
» SQ – 16,893 (A3)
» TN – 17,262 (A2)
New Ranking System - Experiences
• Pros
– More accurate measure of ability
• Cons
– Difficult to communicate a complex system
– Individual sport ratings not universally liked
– Players like rating increasing if they play a tournament
Accuracy of system vs. Encouraging people to play
Set Score Analysis
RQ1: In Which Sport is it Easier to Win Big?
• In general
– Difficult to compare due to very different scoring systems
• Racketlon opens up avenue for comparative analysis
– All points carry the same value
– RQ1 widely debated in the community
» Table tennis with all the spin?
» Badminton with consistent offensive clears?
» Squash where the lines of the court interfere less?
» Tennis due to technique that is hard to master?
Analysis Approach
• Racketlon rules offer harmonized scoring in the sports
• Results from Jan 2014 available in Tournament Software
– Extracted all FIR events and ERA events
– 8,776 matches
– Avg points/match: TT 31.7, BD 32.1, SQ 31.5, TN 17.4
• ERA’s new ranking introduced player ratings in individual
sports
• Analyzed set scores between players of different rating
Results and Discussion
• Table tennis spin control the dominating factor?
• Hypothesis:
– Higher standard players have less variance in their scores
• Does this apply to all racket sports?
RQ2: Do Better Players Play Tighter Sets?
Analysis Approach
• For players of similar skill level (same ERA sub class)
– Analyzed the variance in net score
Results and Discussion
• Table tennis again stands out
– Higher level more risky offensive game?
Table Tennis Badminton Squash Tennis
(Better sub-classes to the left)
Cross-Sport Rating Correlation
RQ3: Which Racket Skills are Correlated?
• Are strong badminton players also good at squash?
– Volley game, straight ground strokes
• Or table tennis and tennis have more in common?
– Top spin, diagonal ground strokes
Analysis Approach
• Extracted all players’ ratings in individual sports from Mar 2015
– Also the total racketlon rating
• Consider the rating on a ratio scale
– Calculated Pearson correlation
Results and Discussion
Results and Discussion
• No pairing stands out
– Player good at racketlon often good at the individual sports
Total TT BD SQ TN
Total 1.00 0.80 0.80 0.84 0.70
TT 1.00 0.57 0.60 0.51
BD 1.00 0.62 0.49
SQ 1.00 0.53
TN 1.00
Wrap-up, Implications and
Future Work
Threats to Validity
• Complete tennis sets rarely played
– Results on table tennis, badminton, and squash more
reliable
• Generalizing to racket sports in general
– Racketlon rules introduces a certain mentality
• Based on data from only one year
– Future analyses should use more data
• ERA Ranking might not be tuned yet
– Replications needed
Conclusion
• Comparing racket sports difficult due to very different scoring
systems
• Racketlon enables comparative analysis of racket sport set
scores
• ERA Ranking provides player ratings in individual sports
• We present a novel analysis of racket sports
• Table tennis stands out
– Easiest racket sport to win by big margin (RQ1)
– Players of LOWER ratings play tighter sets (RQ2)
• All racket sport skills are correlated (RQ3)
Practical Implications
• Racketlon Training Regimes
– Results suggest the importance of table tennis practice
– Hypothesis: Mastering the table tennis spin is a key factor
» For damage control against much stronger players
» To win big against much weaker players
• Racketlon Match Tactics
– Focus during table tennis essential
– Different rating => big margin
– Two strong players => net score varies much
Future Work
• Analyze more data as it gets available, e.g., at the end of the
season
• Design an explanatory study to understand why table tennis
stands out
– Test our hypotheses
• Complement the statistical analyses with a qualitative study
– Run interviews with
» active players?
» table tennis specialists?
» racketlon tournament organizers?
– Conduct a survey among active players
Photo credits
• Table tennis – Flickr: Gmarziou
• Badminton – Flickr: mathias_dekempeneer
• Squash – Flickr: dohastadiumplusqatar
• Tennis – Flickr: Stevenpisano