New formula predicts AFL ladder position based on player injury: Deakin

In a first for Australian football, a Deakin researcher has developed a formula to determine the impact of AFL player injuries on where a team is likely to finish on the ladder at the end of the season.

The study from PhD candidate within Deakin’s School of Exercise and Nutrition Sciences, Daniel Hoffman, is published in a recent edition of The British Journal of Sports Medicine.

It investigates the relationship between AFL teams losing their most valuable players to injury and their ladder position – and ultimately their chances of making the finals.

Mr Hoffman said his research showed that an injury-free season among key players contributed to Richmond’s successful 2017 campaign, and is also a factor in Brisbane making their first finals series in 10 years.

Mr Hoffman said it may sound obvious that when fewer key players were lost to injury, a team would go further up the ladder, but his study removes any guesswork and also includes a formula teams can use through the season to predict ladder position based on injuries.

The formula quantifies injury cost to a team by weighting a player’s injury to their importance to the team, using five measures of player value. The study found:

  • If a team’s 10 most valuable players missed a combined total of 27 matches, the team would typically finish 9th or lower, hence missing the finals series.
  • If a player in the top 10 most valuable players missed nine matches in a season through injury, the team would lose 1 ladder place.
  • Player match availability weighted by player value was higher for finalists than non-finalists and explained seven per cent of the variation in the ladder position of teams.
  • Teams where no valuable players missed a match in the season were 12 per cent more likely to play in the finals series.

Mr Hoffman looked at 15,289 injuries causing players from 18 teams to miss 51,331 matches between 1997 and 2016, using data provided by the AFL and its clubs. He analysed the associations among injury measures and team performance in reaching the finals series and where teams would finish on the ladder.

“We know that injury does influence team performance, and this study supports what we already know,” Mr Hoffman said.

“But what’s important is these findings give coaches more accurate data on where to focus resources in booking their team a place in the finals.”

The paper ‘Is injury associated with team performance in elite Australian football? 20 years of player injury and team performance data that include measures of individual player value’ can be found at here.

The Deakin research team included PhD Candidate Daniel Hoffman, Deakin colleagues Dr Dan Dwyer, Dr Steven Bowe, Professor Paul Gastin and the AFL’s Head of Health, Safety and Laws, Dr Patrick Clifton.

/University Public Release. View in full here.