AFL Pressure Gauge

Can you evaluate an AFL coach's future objectively using only data?

The future of an AFL coach can be evaluated objectively using only data, but in order to fully answer this question, we must first determine what is expected of each coach.

What this means is that we cannot reasonably expect the coach of an up-and-coming team to have the same win percentage over the past 20 games as a coach whose team has been a flag contender for multiple years. Therefore, to compare the two coaches, we need to get creative.

The AFL Pressure Gauge from Stats Insider enters the picture here. Our AFL Pressure Gauge dynamically shows each coach in the AFL and the level of pressure we believe they are under based on a number of key factors. This is not a ride-or-die assessment of who is about to be sacked, but rather an indication of which coaches might be noticing their seats getting a little warmer each week.

How Former Coaches Fared on the AFL Pressure Gauge Before Losing Their Jobs

As you can see from the table below, AFL coaches who get close to or fall below zero are at much greater risk of being sacked.

* - Had one or more full seasons remaining on their contract

So how can we tell which AFL coaches are under the pump and which ones have secure jobs?

Using AFL Line Betting

Let's start with AFL line betting as this variable makes up the majority of our theory when analysing the success of coaches.

Through line markets, we can deduce an expected margin between the two teams before every AFL game.

It is ideal for this exercise because it does a lot of the hard work for us. If you beat line, you have met or surpassed the expectation; if you fall short, you haven't.

This is a good start, but if we stop there, we would only have a chart of coaches who have covered the line more frequently than others, and this will trend towards parity, so we need to look further into the data.

Winning Is the Name of the Game

AFL coaches should ultimately win, regardless of the margin.

In order to account for this, we don't grade coaches too harshly if their team is a heavy favourite yet barely beats the line.

This stops successful coaches from unjustly falling down the list – even when they are winning matches – just because their team is already expected to be really good.

Length of Coaching Tenure

How long a coach has been in the role is another factor we've included in the algorithm.

We reduce the "pressure multipliers" (i.e., the variables that determine the pressure a coach may be under) for coaches who are new to a club to give them time to adjust to their role.

But each game they coach increases this, and after about 60 games (or three seasons) with the same team, the "new coach" effect is completely gone.

Publicly Known Contract Status

Clubs generally don't like to pay out sacked coaches whose contracts still have years to run. In light of this, we give coaches positive multipliers for the years still left on their publicly reported contract. It stands to reason that a coach whose contract is up that season would be under more pressure than one with three seasons left.

Finals Performances

While some coaches are expected to feature heavily in the AFL finals, others have exceeded expectations just by being there.

We view finals games similarly to home-and-away matches, but with some important differences.

If a team doesn't live up to "expectations" in a final (failing to cover the line), and the coach's rating is deemed "negative" for this match, we don't penalise the coach as harshly as we might have for a home-and-away result. On the other hand, if the coach's rating is "positive", the coach gets a bigger boost than they might expect normally.

This effect is more pronounced the deeper into the AFL finals a coach goes.

Team Experience

The last variable contrasts the team a coach was coaching that day's average player experience (games played) with their opponent's average player experience.

This factor can be important in working out what phase of team development or a list build a club is currently at. The more experienced a team is, the higher the expectation that it should win.

Conversely, the less experienced the team, the more we can assume that the expectation of winning is lower.

How to Read the AFL Pressure Gauge

The number next to each coach's name represents their current score. The coach is under more pressure the lower the score. While coaches with scores above zero are typically seen to be safe, coaches with scores below zero have been known to lose their jobs in the past.

Stats Insider's AFL Pressure Gauge is updated every Tuesday after each AFL round with the most recent data.