The question of what factors contributed to success in the Rugby World Cup (RWC) is frequently debated and subject to many opinions. Empirical Rugby, over a period of months, undertook a specific academic research initiative to explore past outcomes in the RWC tournament from 1987 – 2011. Our mission was to test some of those subjective opinions and find out if they stood up to empirical scrutiny. We also set out to establish new findings.
Our main empirical finding is that success in past RWCs was to a large degree predetermined and explainable empirically. The factors tested were a combination of national fundamental characteristics, and then features specific to both unions and teams. In general terms, the effects varied in importance depending on the individual stages of the tournament being considered.
To coincide with RWC 2015, we invite you to explore the other posts on this blog, which examine the findings in more detail and to join us in a conversation on RWC and the game in general.
The main findings were:-
1. National Characteristics
National socio-economic features are relevant, because RWC is an international tournament. The 20 participants in the tournament represent their national unions.
Perhaps surprisingly, we found that GDP per capita had no apparent effect, at any stage; and a larger population was a negative indicator, in the latter stages. Historical, geographic and climate variables also had effects. For example, having land-mass in geographic tropics had a negative effect on a team’s prospects of progressing through the early stages, suggesting that rugby is better suited to temperate climates.
2. Union Specific
We found that rugby playing tradition was important at all stages. Based on World Rugby data, we also found that the size of the pool of registered players had an effect at the quarter-final and final stages.
3. Team Specific
Using ESPNScrum.com data, we found positive effects for both win percentage in the four years prior to each RWC, and of a higher World Rugby ranking. In contrast, a higher number of average caps was a negative indicator as regards reaching the quarter and semi-finals respectively. We also found that having a higher percentage of points scored by foot, again in the four years prior to each RWC, had a positive effect on winning the final. We also found some effects for team physique, especially average scrum weight, which was important in the latter stages of the tournament.
 The research is subject to standard caveats for this type of analysis including in relation to possible sampling effects. It is also not “forward-looking” in nature.