2020 TRI NATIONS: NEW ZEALAND VERSUS ARGENTINA - ADVANCED ANALYTICS
This past weekend the Argentina Pumas defeated the New Zealand All Blacks for the first time ever as part of the 2020 Tri Nations competition. It was a historic victory where the Pumas had to overcome the challenges of preparing for the test match while training under pandemic restrictions in Argentina, and without any meaningful games leading up to the test match. There were no lack of opinions about what happened in the game but do the numbers support the perceptions of what went wrong or right for both teams? Here are the traditional statistics that were used to summarize the game:
TABLE 1: Summary of traditional game statistics for the Round 3 fixture between New Zealand and Argentina in the 2020 Tri-Nations tournament.
I intentionally removed the identities of the teams because I want to challenge you to identify which team is New Zealand, and which team is Argentina. If it’s not clear which team won the game based on these numbers, it raises the question as to whether or not these “stats” are correctly tracking aspects of the game which contribute to wins? The hallmark of a good “stat” is if the team that does better in that measure wins the game more often than not, then it’s probably worth tracking and paying attention to.
So what do the advanced analytical numbers say? The measures presented in this analysis have been vetted with larger data sets from the Rugby Championship over several years (2016-2020), and they have consistently been found to correlate strongly with winning. This is by no means a comprehensive list, but it did identify specific areas that had an impact on this particular game.
KEY AREA #1 - RED ZONE EFFICIENCY
It is not a secret that the majority of tries are scored from the area of the pitch located between the opposition 22m line and the goal line (a.k.a. the Red Zone). There is a school of thought that counting the number of possessions that a team can generate in the Red Zone is way of assessing the effectiveness of a team’s attack. This game was a good example of why this line of thinking can be problematic. In the game, New Zealand was able to generate 10 Red Zone possessions while Argentina was limited to only 2. Does this mean that New Zealand had the better attack? Well, not necessarily. What is more important to consider is what a team does with their possessions once they get into the Red Zone. New Zealand was able to generate 7 net points from 10 Red Zone possessions. This resulted in a points per possession of 0.7 which converts to a 10.0% efficiency. By comparison, Argentina was able to generate 3 net points from only 2 Red Zone possessions (1.5 points per possession, 21.4% efficiency). Thus, while New Zealand was able to generate 5x more Red Zone possessions compared to Argentina, the Pumas were more efficient with the possessions they had (Figure 1).
FIGURE 1: Red Zone efficiency for Argentina and New Zealand (Tri Nations Round 3 – November 14, 2020). Efficiencies from this game were compared to historical averages from The Rugby Championship (2016-2020). Competition average over the same period is in orange.
What’s interesting to note in the figure is that Argentina actually performed to their historical average in Red Zone efficiency. On the other hand, New Zealand vastly underperformed in the Red Zone with an efficiency about one-third of their historical average. Sceptics may point out that regardless of efficiency, the All Blacks still scored more points in the Red Zone compared to the Pumas. While this may be true, it has to be balanced with the fact that if teams struggle to score in the Red Zone, they can compensate by scoring from other areas of the pitch. Which brings me to my next point…
KEY AREA #2 – C ZONE EFFICIENCY
The C Zone is defined as the area of the pitch between a team’s own 22m line and the 50m line. This is a tricky part of the pitch because it represents the opportunity to score some lower probability points from long range, but also presents risk because turnovers/penalties give the ball back to the opposition on a shorter field. Figure 2 demonstrates that Argentina was much more efficient in the C Zone compared to New Zealand.
FIGURE 2: C Zone Efficiency for Argentina and New Zealand (Tri Nations Round 3 - November 14, 2020). Efficiencies from this game were compared to historical averages from The Rugby Championship (2016-2020). Competition average over the same period is in orange.
The Pumas were able to generate 9 points from 3 possessions originating in their C Zone which ended with 3 penalties conceded by the All Blacks (Video 1). Pumas benefitted from these penalties as Nicolàs Sanchez converted all 3 opportunities into points. This is why Argentina had a positive C Zone efficiency. In contrast, the All Blacks were not able to convert any of their C Zone possessions into points and in fact 2 of their possessions resulted in points for the Pumas. This is why New Zealand had a negative C Zone efficiency.
VIDEO 1: Argentina generating points on 3 of their C Zone possessions (Tri Nations Round 3 – November 14, 2020).
Again, what is remarkable is that the Pumas vastly outperformed their historical average by improving their C Zone efficiency by 11.1%. In comparison, the All Blacks underperformed by 5% in C Zone efficiency due to the fact that they gave the ball back to the Pumas which directly resulted in scores, when historically they were able to score more points than they conceded in this part of the field.
KEY AREA #3 – MISSED TACKLE IMPACT (MTI)
In a previous post MTI was introduced as a robust measure of defensive performance due to the fact that it had a much stronger correlation to winning when compared to other traditional measures such as the number of missed tackles and tackle completion percentage.
TABLE 2: Defensive metrics for Argentina and New Zealand
(Tri Nations Round 3 – November 14, 2020).
In the post where MTI was introduced, values were presented as a negative number with 3 decimal places. For this analysis, MTI measures were converted to a percentage as I think that is easier to understand. Thus, instead of saying that a missed tackle for the Argentina had an expected points value of -0.313, it’s easier to restate that 4.5% of missed tackles for the Pumas resulted in scores by the opposition. New Zealand was 10% worse in MTI, meaning that 15.5% of their missed tackles contributed to scores by the Pumas. The average MTI for the Rugby Championship (2016-2020) was -23.5% which suggests that both teams did well on defence, but relative to this average the Pumas were exceptional. This passes the “eye test” as most fans who watched the game should agree that the Pumas defence was outstanding.
The All Blacks underperformed in the Red Zone. Their 10% scoring efficiency was well below their historical performances in The Rugby Championship.
The Pumas were able to find some scoring from the C Zone and were much better in this part of the field compared to their typical performances. The All Blacks underperformed in this part of the field and this resulted in some points being gifted to the Pumas.
The Pumas were exceptional on defence – particularly when it came to minimizing the impact from missed tackles. In addition, they significantly reduced the scoring efficiency of the All Blacks in the Red Zone.
The 3 metrics covered in this post were selected because they identified some interesting trends – they are by no means perfect and the only metrics that can be used to analyze a game. What we hope to convey is that these new measures correlate better with team performance than traditional statistics. The hope is that you will take time to process these measures and the insights they provide. In future posts we will introduce some more metrics to increase our literacy within advanced rugby analytics.
P.S. For you rugby nerds who are wondering about the identity of Team 1 and Team 2, I’ve left a few hints within this post. If you really want to know which is which - I’m not going to reveal the identifies - you should be able to figure it out from the information provided. Have fun!!