The joy of stats
Penalties in rugby are often a point of contention for fans, players and coaches.
But how much of an impact do they have on the outcome of games?
Using data on the Sanzar website we looked at penalties in Super Rugby over the past three seasons.
Initially the idea was to look at whether referees awarded more penalties to home rather than away teams.
And, since 2012 in Super Rugby, they do. Awarding an average of 9.6 penalties per game to away teams, compared 10.4 for home teams.
But less than one penalty per game more to home teams isn't really all that surprising.
Yes, home teams have received slightly more favourable treatment from referees, but that discrepancy could be accounted for by teams generally performing stronger at home than away, thus forcing their opponents into giving away more penalties.
But is winning the penalty count even an advantage? From our sample of 343 Super Rugby games (which spans from the beginning of the 2012 season to last weekend), it would seem there isn't much of an advantage to winning the penalty count. In fact, it may even be a disadvantage.
Of those games, the team that won the penalty count also won the game 149 times. Once the 39 games in which the penalty count was tied are discounted, that equates to a winning percentage of 49 per cent.
However, in a lot of those games (68) the penalty count was won by a solitary penalty.
It's when you take away those games and look just at the games in which the penalty count was won by two penalties or more that things get interesting.
In Super Rugby, the bigger the discrepancy in the penalty count, the greater the chance the team that was on the wrong side of the count won the game.
If that doesn't quite make sense, perhaps the chart below will make it clearer.
The horizontal axis shows the discrepancy in the penalty count and the vertical axis shows the winning percentage of the team that was on the right side of that penalty count.
This isn't to say the key to winning games is to give away more penalties than your opponents, or that this is a tactic teams employ (although it may be), just that a correlation exists between being awarded less penalties than your opponent and your chances of winning that games.
As you can see, as the gap in the penalty count increases, the chances of the team that won that penalty count also winning the game decreases.
So given these numbers, we'd expect at least some of best-performed teams of the past three seasons to be topping penalty counts.
And it turns out the team that has conceded the most penalties per game is the back-to-back champions the Chiefs. And, not only do they concede the most penalties per game, they have the worst penalty differential - conceding 2.08 penalties per game more than they are awarded.
Use the chart below to compare Super Rugby teams by penalties awarded, penalties conceded and penalty differential per game and total competition points since the start of the 2012 season.
Only six of the 16 teams that have played Super Rugby since the start of the 2012 season have a negative penalty differential, but three of those teams - Chiefs, Bulls and Brumbies - feature in the top four for competition points won in that time. The other three - the Reds, Highlanders and Hurricanes are eighth, ninth and 11th respectively.
Of course it's possible that these numbers are a symptom of style of play more so than a deliberate tactic to concede penalties.
It may be that the Chiefs are more aggressive at ruck time and concede more penalties as a result, or that they hold possession less, making them less likely to be awarded penalties and more likely to concede them.
These numbers can tell us what is happening, but they can't tell us why.
Why do you think more successful teams have generally conceded more penalties than their opponents in Super Rugby in recent seasons?