Analysing the Dark Art
rugby365.com reader, turned columnist, Anton van der Merwe in his Statistically Speaking series takes a look at scrum stats.
The art applied by the practitioners of the rugby scrum is sometimes referred to as a dark art. You might very well appreciate just how dark, once you ponder the scrum statistics for the first nine weeks of the Super 14 season in this addition of Statistically Speaking.
Scrum Incidents
The first graph compares scrum incidents based on the nationality of the team putting the ball into the scrum versus the nationality of the opposing team. A scrum incident is defined as a reset, scrum ball lost, a penalty, a free kick, a collapse or a wheel. Two things to keep in mind while looking at the stats: (1) we have had 1,011 scrums in the Super 14 so far, thus a sizable sample, and (2) the overall scrum incidence ratio in the Super 14 is 0.77 incidents per scrum (or 7.7 incidents for every 10 scrums).
New Zealand teams on their ball against South African opponents have the lowest overall scrum incidence of 0.6 incidents per scrum. New Zealand teams also have the biggest variation based on who their opponents are, going from 0.6 against South African teams to 0.91 against Australian teams (i.e., a 51.7 percent increase!). The stat that stands out like a sore thumb in this graph is for Australian teams. On their own ball, Australian teams pretty much average 1 incident per scrum regardless of who their opponent is.
What is up with Australian scrums?
What do Australian teams gain – if anything – from their scrum tactics? In the scrum it takes two to tango, meaning the opponent must factor in the analysis. The second graph provides information on scrums lost (tighthead or wheeled – the ultimate prize of the scrum contest) by nationality of the team putting the ball in versus the nationality of the opposing team.
As can be seen here Australian opponents (the orange bars) are the most successful at claiming scrum scalps on the opponent’s ball. They have caused 10 turnovers at scrum time, the majority of these however come against other Australian teams (i.e., 6 of the 10). New Zealand opponents (the black bars) are a close second with 9 turnovers and most of their success (five turnovers) also come against their countrymen. South African opponents (green bars) are the odd ball out in this regard, having most of their success against New Zealand teams and none against their countrymen.
Looking at ball security at scrum time Australian teams have been turned over 11 times and New Zealand teams 13 times! South African teams are by far the most secure on their own scrum ball, conceding only 2 turnovers in the tournament so far. Although Australian teams affect the most scrum turnovers they also loose all of that advantage by being turned over more (10 gains versus 11 losses). Net gain/losses at scrum time are +5 for South African teams, -1 for Australian teams and -4 for New Zealand teams.
The New Zealand stat is clearly the more intriguing. Their 13 turnovers conceded are 2 more than the Australians’ 11 and a massive 650 percent higher than the two for South African’s teams. Are we in an era where New Zealand scrums are vulnerable?
Finally, the Worst so Far and Worse yet to Come?
Which individual teams are the worse offenders on their own ball and which team the toughest scrum opponent (or spoiler, if you wish)? The two worst teams for scrum incidents on their own ball are the Waratahs with 1.4 incidents per scrum followed by the Brumbies with 1.1. The worst spoilers are the Chiefs (1.05 incidents on an opponent’s ball) followed by a tie between the Western Force and the Cheetahs each with 1.0. No wonder the game between the Waratahs and the Western Force turned into a nightmare. On the Waratahs’ ball that game saw an average of 4 incidents per scrum! But don’t despair, the two top dogs on the scrum incidence stat list (the Waratahs and the Chiefs) must still play each other. That will happen in Week 13 …
In the next column we will add the referee dimension to the scrum stats.
