Sports

What the AFL has learned from the NBA — go long or go home

On first view it is perhaps hard to imagine game plans from the NBA being easily transferable to the wide expanses of an AFL oval.

And yet a recent trend for some teams to encourage their players to launch more long bombs on goal may well have its roots on the hard courts of the US.

The same statistical analysis that has made three pointers in basketball the vogue go to shot is being deployed to inform contemporary footy wisdom.

Buddy Franklin and LeBron James may have more in common than just their physically imposing physiques.

Paul Seedsman of the Adelaide Crows scores a goal a goal against the Sydney Swans at the SCG, Friday, April 20, 2018

For much of the game's history, tactical evolution in Australian Rules football was glacially slow.

External Link: Buddy Franklin bomb: tweet

Coaching precepts were handed down from generation to generation. Ideas would occasionally cross-pollinate between the major football states at their intermittent carnivals, but genuine lateral thinking was rare.

The code's regional insularity tended to stifle innovation.

The advent of televised sports began to alter that, giving Australian footy coaches a window onto the world.

During the 1980s, Fitzroy implemented a revolutionary huddle from the kick-in, which was at least partly based on the blocking and running patterns seen in American football. In the 1990s, Fremantle employed a water polo-inspired strategy dubbed "chip and draw". And in the 2000s, Hawthorn borrowed from the zonal marking and pressing strategies used in soccer to develop its famous cluster.

In 2018, basketball looks like the latest sport to cast its influence across the AFL.

All eyes on the NBA Finals

Millions of people around the world — including many AFL players and coaches — have been glued to the NBA playoffs over the past few weeks.

The NBA has gone through its own recent tactical transformation. Through statistical analysis, teams have gradually identified and exploited the highest-value shots on the hardwood: three-pointers and layups.

Midrange shots — or 'long twos' — have been deemed inefficient and largely relegated to an option of last resort.

Houston Rockets guard James Harden (13) shoots a three-pointer during the first quarter against the New Orleans Pelicans

The Houston Rockets made a league-record 1,256 three-pointers during the NBA's 2017/18 regular season. In doing so, they became the first team to shoot more threes (50.2% of shots) than conventional two-point field goal attempts.

The maths behind the explosion of three-pointers is simple.

External Link: AFL kicking stats: tweet

If made, the shot is worth 50 per cent more than a two. At the same time, an NBA-quality player has only a slightly lesser chance of missing from outside the arc than just inside it.

Australian football has its own arcs, although at face value there is no obvious scoring incentive to shoot from beyond them.

The league has experimented with nine-point "super goals", but, so far, they have been confined to a pre-season novelty. Nevertheless, some in the sport are beginning to believe the logic that has driven the NBA's three-point revolution might yet have practical applications in the AFL.

"In basketball, teams shoot from deep because there is an acknowledged benefit — an extra point than if you shoot from closer to the hoop," said HPNFooty analyst Cody Atkinson.

"In the AFL, the benefit is harder to immediately discern, but the numbers are showing us that it still exists."

The relative value of 'scoreboard equity'

During games, some coaches like to refer to the notion of "scoreboard equity". Simply put, it is the value of their team's current field position and quality of possession assessed in scoreboard terms.

For example, if a player has the ball in the middle of the ground, it is theoretically "worth" one point on the scoreboard to their team. One point is what the average AFL team will manage to convert a centre clearance into.

A player in possession within 50 metres of goal will generally have a higher scoreboard equity than one who has the ball beyond the arc.

But there is an emerging school of thought that the risk of passing the ball from a position just outside 50m to a contested situation closer to goal might not be worth the difference.

"The value of shooting at goal from long range comes from reducing the chance of a turnover," said Atkinson.

"Our research has found that teams earned more than double the points per inside 50 when they shot directly from outside 50, compared to when they passed it inside the arc."

The following goal-kicking accuracy map, designed by Port Adelaide's performance data scientist Robert Younger, shows the AFL-average accuracy for set shots within different zones in or near the forward 50.

Average set-shot accuracy in the AFL.

The average AFL player has a set-shot conversion rate of between about 30 per cent and 50 per cent from just beyond the arc, depending on how acute the angle is. The rate improves for shots closer to goal, rising to 90 per cent and above for those from within 20 metres.

Shots from open play (not included in the above chart) have a lower average accuracy than set shots in most corresponding sections of the field, while following a similar pattern of steadily increasing percentages the nearer they are to goal.

External Link: Seedsman bomb: tweet

The question now being asked is even if a player has less than a fifty-fifty chance at kicking a goal from outside 50 metres, is the alternative of passing to a team-mate inside 50 any more likely to result in six points?

Atkinson believes not, pointing to the NBA's prevailing "layups and three-pointers" philosophy as a useful analogy.

"We could refer to set shots within 20 metres of goal as footy's layups, because they're converted into goals about 90 per cent of the time, but require precise entries to set up," said Atkinson.

"Shots from outside 50 are converted into goals about 45 per cent of the time — but they're also a bit like basketball three-pointers because they force defenders to move up to defend you, opening up space for shots closer to goal.

"All other attempted inside 50 entries are like the NBA's 'long twos', in that they're of least value to an attacking team, turning into about 0.6 points every time they occur."

Can he kick it? Yes he can

HPNFooty's analysis shows that AFL teams can improve their efficiency by maximising their "layups and three-pointers" at the expense of midrange shots. Of course, for the strategy to be effective, clubs need to have an arsenal of long-kicking players.

"Having a guy who can kick goals on the run from 55 metres like Paul Seedsman, who plays more midfield than forward, is a real weapon to have higher up the ground," says his forward line coach at the Crows, Josh Francou.

"We also have guys in attack who can do it like Tex Walker and young Darcy Fogarty."

According to Francou, the principles behind modern basketball theory are already being applied in Australian football, even if they are not explicitly referenced.

Lance Franklin takes off in celebration after kicking a goal.

"Players who can kick goals from outside 50 are really important, primarily because there's one fewer connection to set up another shot," he said.

"It removes the need of having to find another mark inside your forward 50, which decreases your risk of turning the ball over."

Three-pointers and layups. Long bombs and Joe the Goose.

Different sports, but similar strategies.

*Disclosure: James Coventry, Cody Atkinson and Robert Younger are among the authors of Footballistics: How the Data Analytics Revolution is Uncovering Footy's Hidden Truths. The book is being released by ABC Books in June.

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