The effect of the wheeled scrum law in rugby union

1
The effect of the wheeled scrum law in rugby
union   IRB Game Analysis, UWIC, Cardiff CF23 6XD
Jason Williams, Corris Thomas, Rhodri Bown,
Naomi Jones.
2
Contents

• Previous Research
• Background and Definition
• Aim of study
• Method
• Results
• Conclusion

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Previous Research

• Doggart et al (1993)
• Examined Gaelic football and law changes to
  improve amount of time ball in play.
• Found that this was achieved.
• Found other changes within the game that the
  authorities may not have foreseen (possessions
  gained, tackles).

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Previous Research

• Hughes Sykes (1994)
• Analysed the effects of the 1992 back-pass rule
  in soccer.
• Fewer back-passes to the goalkeeper as a form of
  time wasting.
• The intended outcome of less time wasting due to
  back passes was reduced, but at the same time
  other unforeseen areas of the game were being
  affected.

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Background and Definition
New scrum law introduced in 1999
Scrums took up an average of 14 min 23 sec game
time (18) in 1999 (6N 3N)
Example game Number of scrums 35 Total time
taken 18m.56s of playing time taken
up 24 Front row engagements 51 Number of
Penalties/ Free Kicks 7 Penalty
Tries 1 Wheels 13 Collapses 9
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Background and Definition
4 The team throwing the ball into the
scrum When a scrum remains stationary and the
ball does not emerge immediately a further scrum
is ordered at the place of the stoppage. The ball
is thrown in by the team not in possession at the
time of the stoppage.
11 Wheeling Scrum The ball is thrown in by the
team not in possession at the time of the
stoppage.
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Background and Definition

• Resolved number of problems
• Reforms, collapses, time wasting (Thomas, 2002)

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Aim of Study

• Investigate the wheeled scrum rule change
  using notational analysis.

• Hypothesis The amount of possession gained
  through winning or losing in the scrum, with a
  clean strike of the ball, is decreasing

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Method
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Method

• Real-time software
• Access Database with a VB front end
• Series of queries to access data

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Method

• Tested for reliability using percentage
  differences for inter- and intra- operator
  reliability (Hughes et al, 2002)
• Error percentages of less than 5
• Examined using Kruskal-Wallis and Mann-Whitney.

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Results
The Mean of Unclean Scrums in 6 Nations and 3
Nations Over a 4 Year Period
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Results

• Kruskal-Wallis - significant difference in the
  data
• Mann-Whitney - significant difference (p lt 0.05)
  in the 6 Nations (6N) and Tri-Nations (3N) with
  the year preceding the law change (1999) and the
  year after (2000).

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Results

• Mean difference of 16 between the two game
  groupings in 2000.
• Means level after the initial change

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Results
The mean of scrums in 6 Nations and 3 Nations
over a 4 year period
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Results

• Kruskal-Wallis - significant difference in the
  data
• A post-hoc application of a Mann-Whitney test
  indicated that there was a significant difference
  (p lt 0.05) in the 6 Nations, but not in the Tri
  Nations.
• Means level after change

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Discussion

• Possible reasons
• Interpretation by referees (North v South)
• Six Nations competition before Tri Nations
• Scrum considered more of an area for
  competition in Six Nations

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Conclusion

• Significant change after law change
• Different effect on Tri Nations and Six Nations
• Level out after time
• Initial change in game followed by
  acclimatisation
• Expected outcome? Reduction in competition?

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Conclusion

• Future work
• Further analysis of Pen For/Pen Against
• Further analysis of scrums won lost
• Analysis of games at different levels
• Examination of decrease of number of scrums in a
  game

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Questions
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The effect of the wheeled scrum law in rugby
union   IRB Game Analysis, UWIC, Cardiff, UK,
CF23 6XD Jason Williams, Corris Thomas, Rhodri
Bown, Naomi Jones.