Goal-Kicking has long been touted as the single most important skill in Aussie Rules footy. Obviously, if you can't kick a goal, you're never going to win a game. This is why it is surprising that while goal-kicking accuracy has improved over the last 40 years, it has in no way matched the corresponding improvements in other important match skills as footy has become the professional, scientific game it is today.
While this is true (and certainly something for kicking coaches to think about), I'm less interested in the long-term historical shift in Goal-Kicking Accuracy (GKA) and much more interested in what we can learn about a modern day team in the AFL from how they kick in front of the sticks. Do better teams have a consistently higher GKA? Can we use the past GKA of teams to tip upcoming matches? Can it help us predict a premier?
How important is Goal Kicking Accuracy for winning a match?
I guess the best place to start is by looking at just how important kicking accurately is to winning a match. How often does the team with the higher GKA win?
I've collected data on the goal-kicking of both teams in every H/A match from 2003 up until the byes in Rd 11 of 2015 to see how often the team that kicks with greater accuracy actually wins the match. I'm going to be focusing mainly on a team's Goal-Kicking Accuracy which I define as:
I've filtered out games where one team has less than 10 Scoring Shots as these are extreme anomalies (occurring roughly 2 or 3 times a season) and such low scores can easily distort our data. For example, in Rd 20, 2011 against Collingwood, Port Adelaide kicked 3 goals and no behinds after accounting for rushed behinds. This would give them a GKA of 100%, which is nonsensical because they obviously got thumped and even one miss would have lowered their GKA drastically.