AFL Statistics Series #4: Gaining Territory to Score

Back – way back – in my first post in this series, I said that one of the most important measures for an AFL team to win, outside of points for, was its metres gained.

As with points for, there is something obvious about this: a team that scores more is usually going to have more metres gained than its opponent. It is difficult to directly break down a player’s ‘points for’ though, outside of the goals and behinds they directly kicked, and most people would not think that is how to measure a player’s entire impact on their team scoring. Unless the player took it out of the centre themselves someone had to get the ball down to the player that scored.

We do though have a measure for the metres each player gains, at least recently, and with gaining metres being a necessary condition to a team scoring it may help us to better break down and estimate what a player contributes to their team’s score. I expect this to be a main component of my system of player value that I outlined last month.

Metres gained, as I said, are only a recent measure, available on Footywire back to 2015. However, another part of what I will examine below is that it is more or less an extension of older measures that have been with us longer and are more accepted and understood, like inside 50s. That is, valuing inside 50s is similar to valuing metres gained, and vice versa.

I stress here though that I am not heading towards the conclusion that the most valuable players are those that gain the most metres. For a player to gain metres they either need to win the ball themselves, or someone needs to win it for them. When we get to examining the value of winning the ball though, we should be able to express that too in terms of how it contributes to a team gaining metres, and ultimately generating scoring shots.  

Gaining metres leads to scoring – unless you don’t keep the ball

First off: how much does gaining metres tend to lead to more scoring? There is clearly a positive relationship (see chart below), but not an acute one. For example, the Tigers gained by far the most metres in the 2020 home and away season, but were fourth in scoring shots (and also in goals).

Gaining metres by itself of course does not necessarily result in scoring – some teams may play ‘aerial ping pong’, kicking it back and forth to each other without anything crossing the goal line. The next relationship to consider then is that between metres gained per turnover and scoring shots (see chart below – we could also add in team possessions that result in stoppages, but it doesn’t change a lot the point I’m making for now).

Now that looks a bit stronger. The Tigers had more metres gained, but also more turnovers than other top sides, which stifled their scoring capacity relative to the territory they gained. (They also create more opposition turnovers as well, but we’ll get into that when we look at the ‘points against’ side of things.)

Compare this to, say, the relationship between scoring shots and contested possessions, given that contested possessions are often cited as an important factor in winning (see chart below). The relationship is, basically by definition, not as direct as metres gained – teams can advance the ball towards goal through either contested or uncontested possessions, and they differ in the number of possessions they take to get downfield. That is not to say that contested possessions do not matter, but it is within the context of how they ultimately help a team to gain territory that we may get a more accurate overall picture of how they influence a result.

Again, while from a team perspective gaining metres without turning the ball over is what leads to scoring, that doesn’t necessarily mean it’s that simple to measure a player’s value. The players that have high average metres gained per game and high metres gained per turnover tend to be general rebounding defenders like Daniel Rich, Tom Stewart, Shannon Hurn, Jordan Ridley, and Nick Vlastuin. These would still be among the better players in the game, for their ability to kick long and find targets, but they would also often be assisted by teammates, and we’d also need to consider this to get a better picture of their value.

Approximating metres gained with other ‘territory’ statistics

As said above, metres gained are only available to us (I think) back to 2015, but there are other statistics that have been around longer that also capture the concept of gaining territory. Inside 50s and rebound 50s – which measure how many times a player moves the ball int their forward 50 arc, and out of their defensive 50 arc respectively, are available on AFL Tables from the 1998 AFL season onwards.

Between inside 50s, rebound 50s, and scoring shots, we have three measures of when a player has moved the ball past specific points on the field. How well do these relate to metres gained? Fairly well, with players that have high average metres gained tending to have high average totals if we combine their inside 50s, rebound 50s and scoring shots (see chart below). For AFL players who had a minimum of five games in 2020, their estimated average metres gained per game rose on average by:

-          about 60 metres for each increase of one in their average inside 50s;

-          about 50 metres for rebound 50s,

-        about 20 metres for goals (noting that a player can record both a score and an inside 50 in the same kick), and

-          about 30 metres for behinds, also keeping in mind the opportunity cost of missing the goals. 

This approximate estimate of metres gained is within plus or minus 30 average metres per game for about 80 per cent of players. (Of course, I don’t know exactly how metres gained are calculated, so one possibility is that what I’ve just done is re-create something close to the method by which they are worked out.) Without looking in detail at the position of players, it does seem to underestimate metres gained more for ‘outside’ players and wings, and overestimate them more for ‘inside’ midfielders and rucks. However, that doesn’t necessarily count too much against this method of approximating metres – the estimate may actually be a better measure of player value than the ‘raw’ measure, since getting the ball inside the 50 metre arc could carry slightly more value than just the ‘raw’ metres gained would suggest.

What this method does miss though is movement of the ball by players between the 50 metre arcs. Can metres gained also be fairly well estimated from the ways of moving the ball – i.e. kicks, handballs, marks, and hit outs? Yes (see chart below), though as it turns out, at a player average level at least, only kicks contribute positively to the estimate at about 30 average metres gained for each kick. Marks in particular contribute negatively (minus 10), perhaps indicating that players that take more marks are more likely to do sideways or even backwards kicks, that is, chip the ball around the backline.

What this means though is we have come full circle from the more ‘wonky’ measure of metres gained all the way back to a player’s ‘basic’ statistics. A player’s kicks were always a way of indicating to us how much territory a player was gaining. Metres gained may (I believe) measure this more precisely, but as a concept it’s just taking us back to how often and by how much a player is responsible for moving the ball towards the goal posts.

Probably the next part will be to work out which players assist in or set up the gaining of metres. For that, we’ll look more closely at ‘possession chains’ to see which types of possessions are more likely to lead to certain other types.

AFL Rankings: Finals 2020

Richmond may not generally be as dominant as other recent ‘dynasties’, but they are when it counts most.

For the second year in a row, and the third year out of the past four, Richmond are premiers. The Tigers beat Geelong by 31 points in the first ever AFL Grand Final played at night, and the first ever played in Queensland. Directly after their win, much talk turned to Richmond’s place among the very best teams of this (and last) century.

First off, I’ll note that Richmond didn’t even quite end up as the #1 team on my rankings. The Cats held that positon after their huge wins in the finals against Collingwood (68 points) and Brisbane (40 points). However Geelong cannot seem to get past Richmond, having now lost to them in the finals in each of the Tigers’ premiership years.

This suggests that Richmond may not be quite as dominant as other recent ‘dynasties’. The three teams that have won three flags in quick succession in the 2000s were the Brisbane Lions in 2001-03, Geelong in 2007, 2009, and 2011, and Hawthorn in 2013-15. Each of those teams had a higher winning percentage, and higher percentage of points for compared with against, than the Tigers in their premiership year (see table below) – particularly the Cats and Hawks. The Cats and Hawks also perhaps had tougher opposition in contention for the flag, based on the records of other top four sides in their premiership years. Indeed, the ‘all-conquering’ Tigers are not that far above the team that got eliminated in the first week of the finals for three straight years in 2013-15.

Where these Tigers match the other successful sides, and separate themselves from their one-and-done counterparts, is their record in finals. With the exception of Port Adelaide in their preliminary final this year (they also lost their qualifying final to Brisbane), and arguably Geelong last year, they have generally gone through teams like a wrecking ball, with an overall percentage of 164.6%. That is slightly below the Cats, but better than the Hawks and Lions, and of course way better than the Tiger sides that could not make it into the finals’ second week.

So it seems that Richmond’s dominance comes from playing at or near their best when it matters most. In that regard, they are perhaps most similar to the Brisbane Lions teams that were held in such awe as they rattled off three straight flags early this century. The Lions never finished on top, as the Tigers have not done either – at least during the years they won premierships – but they crushed opponents in the finals, with six wins of 40 or more points. Like the Tigers, they seemed to learn how to time their runs just right.

Of course, Richmond’s stepping it up a gear at the business end of the season is emblematic of the performances of their best player, Dustin Martin, who has been the best performer in both the finals and Grand Final of all three of their premiership years. Martin has kicked an astonishing 24 goals in the Tigers’ ten finals in those years, whereas he has averaged closer to a goal per game during the home and away rounds. In the two of those finals he kicked the least goals he racked up 19 inside 50s. He led the team in contested possessions in all three of their Grand Final wins. There has probably never been an attacking force in big games quite like him.

So another season over, and we’ve ended up where we began – the Tigers will remain the reigning premiers next year. As a Richmond supporter, this pleases me greatly; still I hope we never see another year like this, and it is a happier season overall for players and fans (except perhaps this year’s lucky fans in Queensland) in 2021.

AFL Statistics Series #3: Building a System of Player Value

Almost two years ago, I started a series of posts about statistics in the Australian Football League. The aim of the posts was to set out how much I thought the various statistics in the AFL mattered, and how they connected, in telling you how a team was able to score and stop its opponents from scoring.

Part of my interest was also to come up with a system for rating players’ contribution to winning. The AFL Player Ratings system is too complex for an amateur analyst like me to replicate. Other systems are simpler, but are less intuitive in how they measure value. If possible, I would like my system to be in terms of the player’s contribution to the team’s and opposition’s actual scores. While that would be the most elegant way of quantifying value, I’ll go into further below the potential challenges that presents.

After months of false starts and ends, here is where my thinking has led to. This isn’t the system, but it’s how after much consideration I now plan on building it.

Get the ball, move the ball, aim for the goals

As I said in my first post, the aim of Australian football is to get the ball towards and through your goals, and to prevent your opponents from doing the same. All AFL statistics can be classified in terms of these objectives.

The simplest part to capture is the result of a player’s shots on goal. Goals and behinds are easily available, and therefore we can easily see a player’s points per scoring shot compared with the league average. I went through in my second post in this series how this could be measured, and I don’t expect to talk about it too much more in the rest of these posts. The measure can be improved by using expected score, and accounting for kicks out of bounds, but since I’m aiming for a system that can mostly work with simple, historical statistics I’m probably going to leave this part alone and focus most of my exploration elsewhere.

Most of the work will be in the part that is often used to measure the impact of players – how often a player gets the ball and gets it down the field to help their team score (see table above). In other words, how much does a player do to generate shots on goal for their team? Relevant to this will be measures of:

- how often a player gets the ball – i.e. possessions;

- how the player got the ball – did they win it themselves in a contest, or were they part of a chain of possessions for their team; and

- how far they get the ball down the field – which can be measured by metres gained, but also by inside and rebound 50s, and also even just by kicks and handballs. 

The other part of ‘attack’ is how many points a player costs their team by not retaining possession. Turnovers are the most commonly cited statistic in relation to ‘wasting’ possession nowadays. However, many turnovers happen not through a player kicking the ball directly to an opponent, but by kicking to a contest which their team loses, so perhaps we will need to be a bit more nuanced in distributing the ‘blame’ for losing the ball.

Measuring a player’s contribution to defending, at least conceptually, should be the reverse – what does a player do to prevent or not prevent the opposition generating scoring shots? The common defensive measures – tackles, spoils, and intercepts – capture the former. Harder to capture is the latter, i.e. what does a player not do to prevent the opposition from scoring? Potentially this is part of why midfielders tend to occupy many of the top positions on rating systems – they are in more contests, and we can relatively easily measure the contests they win, but it is harder to measure the contests they lose.

Scoring is more variable than possession

As I said above, I would like my system to be in terms of the player’s contribution to the team’s and opposition’s actual scores. Sounds appropriate, right? However, many player rating systems do not have those relativities.

Consider the 2019 Grand Final (see table below). Richmond’s score was over four times greater than Greater Western Sydney’s. On the SuperCoach rating system though, Richmond’s collective rating points were less than 20 per cent higher. That is more similar to the difference in metres gained, and the difference in disposals was even closer – the Tigers had only one more disposal.   

Getting the ball towards goal for a score requires not only having possession, but also having the right sequence of possessions. Usually, it will not be just three consecutive kicks towards goal – it may be two kicks forward, one kick the other way, another kick back, a handball back the other way … until eventually a team gets the ball far enough forward that it scores.

What is the value of what the team’s players did then? Is it how often they got the right sequence of possessions to score? Or is it just how often they got the ball, and got it forward? What is the ‘true’ value of high possession-getters in ‘bad’ teams? That will be one of the questions I wrestle with in future posts.

AFL Rankings: Round 18 2020

Port Adelaide and Brisbane have the home finals, but Richmond and Geelong look to be slightly ahead as the leading contenders for this year’s premiership.

After a home-and-away season unlike any other, we have our eight finals teams. Port Adelaide finished on top of the ladder, where they had spent the entirety of the season. The Brisbane Lions took advantage of a season played largely in their home state of Queensland to finish second. The last three premiership teams – Richmond, West Coast, and the Western Bulldogs – are back for another run, along with recent finals stalwarts Geelong and Collingwood. Finally, a much improved St. Kilda team have made it back for the first time in nine years.

Who do the rankings like for the premiership? In what may be good news for Cats fans, or bad news given how last year turned out, the rankings are picking Geelong for the second straight year (see table below). It is not a pick made with much confidence however, with predictions for several very close matches.

Heading into the finals series the favourite for the premiership is Richmond, followed by Geelong and Brisbane. In response, the ‘hip’ pick for the flag this week seems to be Port Adelaide, with people arguing they were being underrated given they had spent the whole season on top.

While this year’s fixture first seemed like it would be more even than usual, with each team playing each other once and many games at neutral venues, in reality it gave some teams a massive net home ground advantage. (Not the greater home ground neutrality previously suggested on this blog.) As Max Barry at Squiggle has pointed out, with home ground advantage based on state, Port Adelaide played six games with home ground advantage this year, compared with two with a disadvantage. Things were even better for Brisbane, although the exact count of how many games they had an advantage in depends on how one treats their away matches on the Gold Coast.

In contrast, teams like Richmond and Collingwood had no games against non-Victorian sides before they had to leave Melbourne and move into their hubs. Some opposition supporters (and media) rarely miss a chance to point out how many games the Tigers and the Magpies usually get at the Melbourne Cricket Ground each year and therefore how little travelling they do, but really the majority of those games are against cross-town teams that have had to do about as little travel as they have. The ‘real’ home ground advantage comes when playing teams from out of town.

Port Adelaide is definitely a decent chance to win the flag. The 2020 Grand Final however will not be played in Adelaide, but in Brisbane. Of the top four sides the rankings currently do not favour Port in a Grand Final match-up with any of the others – Geelong and Richmond because the rankings consider them stronger teams, and Brisbane because of the Lions’ home ground advantage. The Power are still considered a good chance to make it to the Grand Final though, with potentially two home finals.

Overall though, even Richmond is less than a 30 per cent chance with the bookmakers, and it would not greatly surprise to see any of the top four teams hoist the cup at year’s end. Really, would a winner from outside the top four be a surprise either? Perhaps the main surprise of this year’s AFL finals series – albeit a pleasant one – is that we got to this point at all.

AFL Rankings: Round 17 2020

AFL Rankings: Round 16 2020

AFL Rankings: Round 15 2020

AFL Rankings: Round 14 2020

 Melbourne has powered into finals contention on the back of its ‘fab four’.

The Demons are one of the better teams again

After an excellent 2018, and a disappointing 2019, it was hard to know what to expect from Melbourne this season. The Demons did not start off the season in sparkling form; they lost a close match to Geelong, but otherwise were not overly impressive in their first five matches. The first hint that they may have turned a bit of a corner was their seven-goal demolition of Hawthorn, where their stars (more on them below) went berserk.

In recent weeks, Melbourne has shown some more of that form, and the form that got them into the finals two season ago. They had three successive wins by more than 50 points, which is pretty impressive even when you consider the quality of their opposition (see chart above) – though Collingwood are no easybeats. 

Last week’s loss against the Bulldogs had many questioning whether it was yet another false dawn, but this week’s close win against fellow finals aspirant St. Kilda may have some Demons’ fans believing again. Only the red-hot Geelong Cats have bettered Melbourne’s average adjusted net margin of +27 points over their past five matches.

As much as I sometimes wish to highlight particular players on this blog, generally the contribution of a team’s players in Australian football is fairly even, and a team’s performance is more reliant on the quality of twenty players rather than just a few. Melbourne’s playing list however, is more lop-sided than most.

Big Maxy, Clarry, Trac, and Viney

As of the end of Round 14, Melbourne has four of the top twenty-five players on the AFL’s Player Ratings for the season: ruck Max Gawn, and midfielders Clayton Oliver, Christian Petracca (the #1 player), and Jack Viney.  

While the Player Ratings sometimes is subject to raised eyebrows – such as this week when GWS forward Jake Riccardi kicked four goals and was rated the worst player on the ground – it is fairly easy to demonstrate the value of these players using less advanced measures.

Max Gawn, as is well-known, is one of the most effective rucks in the game. Currently in season 2020 he ranks second for hit outs per game, behind Brodie Grundy. Another part of what makes him really valuable though is his marking around the ground – he ranks seventh for contested marks per game in 2020, well ahead of many other top ruckman (see table below).

Meanwhile, Oliver, Petracca and Viney – as the AFL Player Ratings suggest – are possibly the most effective ‘inside’ midfield trio in the game. (Though Dogs fans will note their star midfield beat them handily last week.) All rank within the top twenty for contested possessions per game, with Oliver (#2) and Petracca (#4) sitting in the top five (see table below). No other team has three of the top 20. Oliver and Viney also rank in the top twenty for clearances per game. All three rank in the top 50 for metres gained per game, with Oliver kicking the ball more this season. Petracca, while not ranking as high for clearances, has continued to be an attacking weapon and ranks second for score involvements.

Will it be enough though to get the Demons into the finals? There’s still eighteen other players in the team who will determine Melbourne’s fate. The recent good form of defenders Steven May and Jake Lever helped get the Demons across the line on the weekend. If they can continue to support their star midfield, then Melbourne could cause some trouble this Septem - … er, October.

AFL Rankings: Round 13 2020

 

AFL Rankings: Round 12 2020

The Geelong Cats have become the most in-form side in the AFL by playing ‘keepings off’.

The Geelong Cats have become more of a premiership fancy over the past couple of weeks, with ten goal wins against St. Kilda and ladder leader Port Adelaide. The Cats have been a perennial finalist since their last premiership in 2011, but have not made it back to the Grand Final since. This has given them the label of essentially being ‘good, but not good enough’. However their two impressive wins has many reporters and commentators suggesting that things may be different this year. 

It may seem odd to say that Geelong were not a contender last year when they finished as the minor premier. They were at the top of these rankings for much of last year, and going into the finals. They did however notably slow down in the second half of the year, with an average net margin adjusted for opponent strength and home ground advantage of +12 points after their big win against Richmond, compared to +32 points in their first 12 matches.

The Geelong team of recent weeks has risen back to the form they showed during the first half of 2019. Over their past five weeks their average adjusted net margin is +40 points (see chart above), which also includes comfortable wins against Fremantle and North Melbourne, and a narrow loss to fellow premiership contender West Coast. Their run of form has given them the biggest increase in ranking points aside from Melbourne over that period, and now has them sitting on top of the rankings.

But as watchers of the Cats over the past two games would know, there is something different about their style of football this year. They seem to have taken a leaf out of the playbook of their 21^st century nemesis Hawthorn, and are favouring more short, precise kicks to hold on to the ball and move it forward.

The Cats play the uncontested game

Geelong leads the AFL this year for disposal, mark and uncontested possession differentials with their opponents, which is indicative of their increased tendency to chip the ball around (see table below). Their advantages were even greater in these areas in their two big wins against the Saints and Power. Last year, the Cats were outside the top four in all of these categories. Over the past couple of years it has been Collingwood, and last year GWS, that have used the high-possession game to most success, but Geelong is proving adept at it this season.

Several Cats have seen their disposal counts rise this year, generally the smaller players around the flanks (see table below). Two midfielders though have really seen their production grow, and have arguably been key to the Cats’ style of play in recent weeks. One is wingman Sam Menegola, while the other is Cameron Guthrie. Their disposal counts have increased significantly even without adjusting for the shorter game time this year; after adjustment their increases are even more impressive.

This is not to say that the Cats have not been good at the contested footy as well. While not as large as their uncontested possession advantage, the Cats also rank first for contested possession differential this year. Big forward Tom Hawkins dragged down an astonishing seven contested marks against Port Adelaide, although the Cats don’t rank quite as highly over the season in this category.

Will things be different this year come finals time for the Cats? It is the question that has been asked for seemingly much of the last decade. But most of their players appear to be in peak form at the moment, and as long as they can keep purring along like this, they’ll give themselves the best possible chance to finally break through to the top again.

AFL Rankings: Round 11 2020

AFL Rankings: Round 10 2020

 

AFL Rankings: Round 9 2020

This week: the Western Bulldogs continue their inconsistent form, and Essendon is exposed by one of the top sides.

Inconsistent Doggies

The Western Bulldogs lost to Richmond by 41 points on Wednesday night in a match they were never really in. It continued the Dogs’ run of inconsistent form this season. It was the Bulldogs’ fourth loss by 39 points or more this season, following big losses to Collingwood, St. Kilda, and Carlton. They have also had four wins by 24 points or more; their win against Gold Coast last week was their only close match.

Based on my adjustments of final game margin for opponent strength and home ground advantage, the Bulldogs have had the most variability in their results this season (see chart above). The standard deviation of their adjusted net margins is +39 points, the highest of any team.

However, the variability in their performances may not be quite as much as their results. Against top sides Collingwood and Richmond the Bulldogs were dismantled, with 13 more turnovers and 13 less inside 50s against the Tigers, and 71 less disposals and 20 less inside 50s against the Magpies. Against the Blues though they recorded more disposals and 12 more inside 50s; they just could not convert that edge into scores. The Saints also largely beat them through better conversion inside 50.

For the season as a whole, the Bulldogs are close to even in their differentials for disposals, contested possessions, turnovers, and inside 50s. Overall this may indicate that the Dogs are not the rising team they looked like in the back half of last year, but they may still have enough to challenge for a finals spot.

The Bombers come unstuck

Essendon may have been starting to feel reasonably confident about its finals chances this year, sitting at seventh on the ladder but with a game in hand that – if the Bombers won – would move them up to third. They were exposed by the Lions on the weekend though, losing by ten goals, and scoring only 29 points.

The Bombers had, up until that point, a reasonably easy fixture. Their win against Collingwood in Round 5 was an impressive one. But apart from that their wins had come against Fremantle, Sydney, North Melbourne, and Adelaide, who have a combined record of 9 wins and 27 losses. Further, three of those wins were by a goal or less.

This was part of why the rankings only had Essendon at fourteenth going into this round. Up until the match against the Lions the Bombers had overall been about average this season. Towards the end of last season though they had been well below average, with huge losses against Port Adelaide and the Bulldogs (see chart above).

While the Bombers will arguably not be playing anyone as strong as the Lions in the next few weeks, their fixture does become harder than it has been to date. Essendon fans would be hoping that the side that played so well against the Magpies is still lurking up in Queensland somewhere.   

AFL Rankings: Round 8 2020

St. Kilda’s improvement this season has been fuelled by its goal accuracy. Have the Saints been better or lucky?

The Saints come marching back

St. Kilda’s impressive win against Port Adelaide at Adelaide Oval in Round 8 moved it up to third on the AFL ladder. So far, this is looking like a significant improvement on last year’s fourteenth-placed finish, and the sixteenth-placed finish the year before that.

On the rankings, the Saints have gained more ranking points this year of any team except the Gold Coast Suns. The Saints have an average net margin this year adjusted for home ground advantage and opponent strength of +12 points (see chart below). This has been driven by impressive wins against Port, Richmond, and the Western Bulldogs. In their last 14 matches for 2019, their average adjusted net margin – also deflated to compare with this year’s shorter quarters – was -16 points.

St. Kilda has scored more points than any team so far this season besides Brisbane. However, in terms of scoring shots per game this year it only ranks tenth. Have the Saints actually improved by as much as the results suggest, or have they got a bit lucky? Or like Tim Membrey’s scissor-kick goal – is it perhaps a bit of both?

St. Kilda suddenly becomes deadly accurate

In recent years, the Saints have been somewhat let down by their inaccuracy when kicking for goal. So far this year, they have been amazingly accurate.

St. Kilda kicked 12 goals and one behind against Port Adelaide, making it the first team in the VFL or AFL in 120 years to win a match when scoring only one behind. Against Richmond in Round 4 the Saints kicked 15.3. Against the Bulldogs in Round 2 they kicked 14.4. That means in their three most impressive wins this season they scored 41.8, meaning they scored at an astonishing and seemingly unsustainable conversion rate of 83 per cent.

The Saints have generated good shots

Many AFL followers with at least a passing interest in more advanced AFL statistics would know of the concept of expected score, which is the score a team would be expected to kick given the location of their shots on goal. A really good resource for this is Stats Insider’s Shot Charting Explorer. This can help us work out if the Saints have been accurate in front of goal because they have been generating good shots, or because they have been converting those shots into goals at better rates than you would expect?

According to Stats Insider’s data, it is more the former. St. Kilda expected score this year given where they have taken their shots at goal from is higher than its actual score. The Saints’ actual scores were only slightly higher than their expected scores in their wins against the Tigers and the Bulldogs. They have still substantially improved their shot-taking from last year, but it is their shot-creating that has been really good.

Up to Round 7 the Saints had taken around 30 per cent of their shots at goal from zero to 24 metres out this year according to the Stats Inside figures, up from around 20 per cent last year (see table below). Less of their shots have come from the 25-49 metres range. Their accuracy is up by at least 10 percentage points from both the below 25 metres range, and the above 50 metres range.

Furthermore, the Stats Insider’s heat maps (see below) show that more of their shots have come from directly in front of goal rather than to the left or right, which is probably why their accuracy has improved. Last year’s heat map is fairly typical of most clubs in its spread around the 50 metre arc. This year’s heat map, once it gets near the goal mouth, is arrow-straight.

Straight shooting Jack

One player who is emblematic of the Saints’ improved goal accuracy is Jack Billings. In 2018, Billings kicked 14 goals and 19 behinds. In 2017 he kicked 23 goals and 36 behinds. West Coast’s Josh Kennedy kicked only three more behinds, and bagged 46 more goals. If Billings had been able to convert at the league average, then he would have added 1 or 2 more points per game to the Saints’ score – small in the context of the overall result, but a sizable proportion of the contribution of one player.

This year Billings has kicked seven goals and just one behind. His actual score of 43 has been 15 points higher than his expected score, according to Stats Insider. In contrast, he scored five goals less than his expected score in 2018, scoring a goal on about one-quarter of his shots from 25 metres or more.

A fair proportion of goal accuracy is random: one year’s straight shooter can be next year’s sprayer – even if you are Ben Brown. If the Saints can keep generating shots as good as they have though, they are on a fairly sustainable path.