Home Advantage in the All Ireland Qualifiers

Quite awhile back I looked at home advantage in Gaelic Football. You can read that piece here. It found that there was home-field advantage in the league but proved very inconclusive in the Qualifiers. Unlike in the league where teams are grouped together based on their standard (form), the qualifiers are an open draw and can pit teams of very different qualities against each other. This has a tendency to skew the data and might mask any underlying home advantage. For example if Kerry were drawn against Leitrim, away from home, there is no way the home advantage would make up for the gap in quality.

With that in mind I decided to look at home field advantage in the qualifiers while taking account of the difference in quality between the two teams.

A note on the data:

  • It includes all qualifier games played on non-neutral grounds.
  • Season 2008 – 2012 as that is when the league went to 4 divisions.
  • This left us 93 games played in a home venue

The Results:

Click to Enlarge

Click to Enlarge

Thoughts

First thing to note is that since 2008 home-advantage does have an effect – regardless of the quality of the 2 teams involved. That in itself is noteworthy. However the results get more interesting when we allow for the similarity in quality between the 2 teams. When the difference between the 2 teams is greater than 1 division i.e. Div 2 v Div 4 we see almost no advantage in being at home. The results are closer to 50-50 which is probably linked to the odds that a team will be drawn home or away (50-50).

As the quality of the teams get closer we begin to see a seemingly bigger advantage to being drawn at home. Where teams are from the same division or only 1 division apart home teams win 60% of the time.

The home winning % of teams when they play opposition from the same division is a startling 81%!! This has only happened 16 times since 2008 and only once between Div 1 teams but that is a big number.

 

*Authors Note: The sample size is relatively small but if we let that stop us doing analysis on GAA we could never analyse anything! 

Agenda Stats

Often people seek out stats that already agree with their own opinion rather than look at ALL the facts.

Colm Parkinson has a problem with GK taking frees and how much time it takes up. His recent tweet:

What do the facts tell us;

17 frees were taken where a genuine effort was made at scoring. 6 were taken by the GK’s & 11 by outfield players. If we look at the averages of the time taken from the free being awarded to the ball being struck.

GK’s AVG; 49 seconds

Outfield AVG: 34 seconds

So GK’s took an extra 90 seconds out of the game than outfield players (15 sec x 6), but that’s assuming it should take the same time to take a free from 45m or further as it does from 13m. I’m not sure this is the case and perhaps over the summer we will get a better idea on this. One thing is for sure they did not waste 5 minutes of the game!

Tyrone v Dublin League Final Preview

Despite only 1 point separating them over the course of the league, Dublin are firm favourites with the bookies for Sunday’s League Final. Taking into account that Tyrone have already beaten Dublin this year is the short price on a Dublin win justified? Let’s take a look at some of the numbers.

Tyrone:

Tyrone’s Shooting % in 2013 is at 47% – not bad but certainly not brilliant. Come Championship time this probably won’t be good enough to lift Sam. What has helped Tyrone is the fact that their opponents have only shot at 42% (Dublin scored 48%). This is a pretty low % and again not something we would expect from Top Teams but some credit must be given to the Tyrone defense for this.

To highlight how good Tyrone have been at keeping the opponents to shooting from distance, the shooting schematic below shows the sheer quantity of (wides and short) shots that have come from outside the main scoring area.

Tyrone’s Attack Efficiency (shots/attacks) is at 81% which is quite good considering the strength of the opposition. 78% is the average for good teams but a few attacks either way can make a big difference here. By contrast Tyrone’s Opponents have had an Attack Efficiency of 83%. This is well above average and shows that teams are not struggling to get inside Tyrone’s 45, but then the pressure comes on and the shooting is a bit erratic. Perhaps of most note is the fact that Dublin had a 94% Attack Efficiency against Tyrone – ominous signs?

How Do Dublin Stack Up

Do Dublin justify their short odds? Looking at their 2013 league campaign their shooting % is only at 45% – best forwards in the country? The have had good some good days and bad ones but their Shooting % has never crept above 50%. Amazingly Dublin’s opponents have preformed better at Shooting %, scoring 48% of their shots. The big difference has been the sheer quantity of shots Dublin have had, but these figures seem to back up the attitude of ‘whatever you score, we will score more’. This attitude seems especially evident in the number of goals scored.

Perhaps the most interesting finding is that Dublin’s Opponents have only managed a 76% Attack Efficiency. This is a striking % and extremely close to what Donegal managed last year. When opponents get a shot off they are scoring with a greater % of shots than Dublin but Dublin are vastly better at stopping the number of shots in the first place. So while all the talk has been of the forward power – perhaps it is Dublin’s defenders that deserve more credit for allowing their forwards get away with such an average return.

The Verdict

A big reason Tyrone won against Dublin is despite the % being similar, they created 10 more attacks and 8 more shots than Dublin. This is a big swing in a 1 point game. Looking at the numbers above it seems that Tyrone will have to restrict Dublin’s possession rather than go toe-to-toe with them in any Shoot Off if they have any chance of winning.

Dublin’s Style

There is a lot of talk about the changing style of Dublin football and the new attacking style Dublin have brought. To see if this is true I went back over the 2012 figures for a comparison*.

Shooting % (Dublin/Opponents)

2012 Championship: 49%/50%

2013 League: 45%/48%

Attack Efficiency % (Dublin/Opponents)

2012 Championship: 82%/80%

2013 League: 82%/76%

 

Notes:

  • The league games analysed this year include every opponent except Cork (to make the samples identical).
  • Comparing League and Championship has some limitations, not least the standard of opponents but as an illustration I think it’s interesting. 
  • Wides are marked with an X and Short with a 0
By |April 24th, 2013|Uncategorized|0 Comments

Do Free Takers Have A More Natural Side

It’s not something you see as much of in Rugby. The place kicker (i.e. Johnny Sexton or Ronan O’Gara) take almost all the kicks at goal, with the possible exception if the kick is simply out of their range, but that is determined by distance rather than what side of the pitch it is. In Football we see a very different strategy – most teams seem to have a free taker depending on what side of the pitch the free is taken from. With that in mind and inspired by @marktaylor0‘s post on Rating Rugby Union Kickers I wanted to explore some of his points in Gaelic Football.

Does Kicking from your more natural side affect the success rates of kicks?

I have taken the most frequent place kickers from the last 2 years as the sample size – which gave me 25 free takers in total. Examining whether as a group these were more accurate from their natural side.

Here are the results.

So for Right footers there is a slight improvement (2.95%) when kicking from the left hand side of the pitch. Nothing dramatic but enough of a difference. The results are quite different for left footers however;

Here we see a much bigger increase in accuracy. 6.73%. Both images prove, to some degree, that there is an advantage to kicking from a more natural side. It’s by no means definitive and there are few other factors I want to explore but for now the evidence seems to suggest the reasoning for having 2 free takers.

By |January 25th, 2013|Uncategorized|0 Comments

Do Kickouts Really Matter?

Ever since I have been a Performance Analyst the first stat I am almost always asked for is ‘did we win our Kickouts?’ It is a commonly held belief that if you win your Kickouts you go along way towards winning the game. But is this actually true? Rather than rely on opinion I decided to look at the figures.

Results

I ran the numbers and in simple terms the team who wins the Kickouts wins the game 56% of the time. Considering sport is a game of inches 56% is reasonably strong. But treating all games the same is not really fair so I decided to delve a bit deeper.

Not All Games Are Equal

I wanted to look at Kickouts by Game Type. The reason for this is that in one-sided games say Cork v Clare Kickouts may matter less than in a more competitive game such as Cork v Donegal. I created 3 Game Types;

  1. Both Teams are Div 1 teams in 2013
  2. One Team is a Div 1 team in 2013
  3. Neither Team is a Div team in 2013

This can seem a bit arbitrary but there is logic to this and in some other research I have conducted the 8 teams in Div 1 in 2013 are the in form teams over the last 2 years.

So does winning Kickouts matter across the different game types? We get some mixed results.

Game Type 1: The team who wins the Kickouts battle in this game type only goes on to win the Match 44% of the time. Therefore the team who wins the Kickouts is more likely to lose than to win.

Game Type 2: The team who wins the Kickouts battle in this game type goes on to win the Match 61% of the time. This is perhaps not surprising – we would expect Div 1 teams to outperform other teams in many aspects of the game not just Kickouts.

Game Type 3: In games involving no Div 1 team (only 6 games analysed) – The team who wins the Kickouts battle in this game type goes on to win the Match 67% of the time. That’s a big number.

Conclusion

This quick bit of research probably throws up more questions than we started with but to be clear; It doesn’t seem Kickouts matter in games involving Div 1 teams but it matters a huge amount in games between teams outside Div 1. Perhaps the results for Game Type 1 are surprising but all I think it does is highlight the fact that primary possession may not be a defining performance indicator among the top teams. This could be down to the structure/discipline Div 1 teams have when defending. We see very different results in Game type 3 – primary possession seems very important. If I was involved in a team outside of Div 1 I would certainly be spending time on Kickouts – but perhaps Div 1 teams don’t need to invest too much time in them.

By |November 27th, 2012|Uncategorized|2 Comments

Some Problems With Stats

As an avid follower of all things statistics it is great to see all the soccer blogs popping up analysing data. This has been made possible in a large way by the data released my Manchester City. What is great to see is the wide range of analysis and critiquing done by the community. In most cases this community operates outside the game i.e. they are not Performance Analysts working within clubs. This allows them a certain amount of freedom to publish things that clubs might consider sensitive information.

I think we have barely even started this process in GAA. There are only a handful of bloggers/journalists using data on a semi-regular basis. For many reasons the evolution has been a bit slow but I wanted to make a couple of points.

1. Averages;

while averages can be very useful they should come with a bit of a warning. I have recently finished a project looking at the the effects the quality of the opposition can have on performance. It was found to be significant. This basically means that when calculating averages I account for the quality of the opposition. I create 1 average for ‘Top Teams’ and 1 for ‘Bottom Teams’ – combining the 2 masks the ‘real’ performance. We can now benchmark our performance not just against the overall average but against a more specific one. Averages alone might mask the true performance.

2. Context;

I will be the first to admit that stats will never tell the whole story. A lot of the time you need to look at video. It can be very difficult to get stats to give you all the context you need – but that doesn’t mean you shouldn’t try. For Example: If you are looking at shooting averages – comparing them to the Championship average is a great start but there are other factors you need to consider.

  • Game Situation: Is a score when you are behind by 1 worth much more than when you are ahead by 10? I would think so and therefor needs to be considered.
  • Game Time: The stage the match is in might also be important (First minute v’s Last Minute). Coupled with the game situation above, scores at different times in the game might also need to be considered.
  • Shot Location: Where on the pitch a player scores from is also important when comparing performances. Inside/Outside the scoring zone for example.
  • Opposition Quality. Against opponents of different quality you will get different results. You need to factor this into any performance % you measure.

3. Sample Size

GAA teams play an extremely small amount of competitive games. For example in last years championship there were 61 games. That’s across 33 teams. Donegal played only 7 games. In contrast Man Utd played 38 games in the EPL alone add on the FA Cup, League Cup and Champions League and you get close to 61 games for them alone. This sample size makes it easier to draw real conclusions from the data. It’s never going to be like this in GAA so we need to work with what we have got – but is worth keeping in mind and we need to be mindful of making statements based on small sample sizes.

 

By |November 19th, 2012|Uncategorized|1 Comment

Is Football Getting Less Competitive?

There has been much talk over the last few weeks about the one-sided nature of some of the games we have seen this year. Rather than just accept this as a common view – lets look at some real data. (Data from 1/5/11 – 26/6/11 — 1/5/12 – 26/6/12)

Total Points Scored

This first graph shows the Total Points scored (on average) for the 2011 and 2012 season. It’s broken down by province.

The only province seeing less points per game is Munster – which could be explained by Kerry & Cork meeting earlier this year than last year. But Munster aside all other provinces are seeing an increase in total points scored. Despite the perception of blanket defenses ruining the game we are in fact seeing an increase in points scored!!

Competitiveness

Perhaps more important than the total scores in a game is how competitive the games have been. The simplest way to measure this is to look at the points difference between winning and losing teams. The graph below shows the picture of this based on the same data as above.

An increase in these figures means the games are less competitive. All but Connacht are showing signs of more competitive football. So despite the perception, caused by some very one sided games, when we look at the overall picture football is as competitive as last year.

This figures might change over the course of the season but comparing this year with the same period last year we can see that total points per game are up and game competitiveness is improving.

 

Gaelic Football World Rankings

The First Unofficial Gaelic Football World Ranking

World ranking is well documented in other sports. I wanted to see if it would be possible to do the same in Gaelic Football. I examined the methods used by Soccer and Rugby and stuck very much to those lines. Once you have the match results data and a formula to follow its an easy enough process.

The Formula:

Result Points: This is quite simple the winning team is awarded 3 points the losing team 0 and if the match is a draw 1 point is awarded to each team.

Match Status: This can be argued back and forth (and no doubt will), but I needed to assign a match importance weighting. The ranking was as follows;

  • Championship Game: 4
  • Qualifier: 3
  • League: 2

Opp Strength: This was by far the hardest to calculate. First I needed a starting ranking I took the league tables from the 2008 season and ranked teams in the order they finished 1 – 33 (rather arbitrary – but as you will see historical results have less of a weighting). I would obviously have preferred to use Championship games but it is very difficult to rank teams in the championship.

That got me my ranking for the start of the 2009 season. Once I calculated a World Ranking based on the method below I used that on going.

Historical Weighting: Again I copied FIFA here, they assign different weightings to games depending on how long in the past they happened. (2009 = 0.2, 2010 = 0.3, 2011 = 0.5, 2012 = 1). Therefore games that happened in 2009 are not as important as games played in 2012.

Ranking Points = 100(Result Points x Match Status x Opp Strength x Historical Weighting)

This is averaged for the 3 years involved (will be 4 years when I add 2012). So here is the current standings as at Jan 1st 2012.

Team Ranking
Dublin 1
Kerry 2
Cork 3
Kildare 4
Donegal 5
Tyrone 6
Down 7
Mayo 8
Roscommon 9
Wexford 10
Limerick 11
Meath 12
Derry 13
Armagh 14
Wicklow 15
Laois 16
Louth 17
Offaly 18
Antrim 19
Longford 20
Sligo 21
Waterford 22
Leitrim 23
Cavan 24
Carlow 25
Tipperary 26
Monaghan 27
Clare 28
Fermanagh 29
Galway 30
Westmeath 31
London 32
New York 33
Kilkenny 34

No doubt there are many talking points in both the tables and the method I have used. Perhaps the league should be less valuable or provincial championships weighted differently than the All Ireland Series. If you have any thoughts on ways to improve this please let me know. I would love to get your thoughts.

By |March 28th, 2012|Uncategorized|1 Comment

All Ireland Final’s – A 100 Year Visualization

I have been playing around with different ways to visualize data. This is a table I have put together for all the All Ireland Final Results since 1911.

Here is a quick guide to what you are looking at.

Left Axis: Winners Total Score
Bottom Axis: Year
Colour: Province
Bubble Size: Margin of Win
Team: Winner

If you hover over the bubble you will get more information such as the runner-up.

 

Love to get your thoughts on this and maybe any suggestion on how it might be improved.

By |January 6th, 2012|Uncategorized|0 Comments

Moneyball & Gaelic Football

What has Moneyball got to do with Gaelic Football?

For those who don’t know, Moneyball started life as a book about Baseball but in reality it has become much more than that. Now a Hollywood movie with the lead character played by Brad Pitt, essentially it is a story of how an underdog team – The Oakland A’s – used statistics to recruit players that all the other ‘big’ teams undervalued.

As the Moneyball movement spreads across the Atlantic it has caused somewhat of a revolution in sports analytics. But there is a problem – coaches, managers and some in the media just want to dismiss the use of statistics in ‘their’ game as nonsense. ‘Stats have no place in Gaelic Football’ is a common statement I hear.

Are the right?

Well… yes and no. The wrong stats will always be wrong. For example on Newstalk radio at the weekend there was a conversation on this topic. One stat that was thrown out was; Kieran McGeeney in the All Ireland Final and how he was taken off because he hadn’t touched the ball in 18 minutes. People are only too happy to use stats like this to make a point of how stats have no place in football.

This stat will never have any use in football – so what he hadn’t touched the ball? It’s the wrong stat to look at. If this is an example of how stats have no place in football then you are right. But my point is that it’s not the right thing to look at – it’s just a bit of information. There is absolutely no context applied to this. Coaches and managers using this information have to apply some game knowledge to interpret this information.

For example

  • Did his man touch the ball in that 18 minutes?
  • How much possession did Armagh have in that 18 minutes?
  • How many possessions do you expect him to get?
  • Does he need to have possession for Armagh to win?
  • Does taking him off have a psychological affect on the team or opposition?

These are all elemnts that would need to applied to this tiny bit of information before it becomes in anyway useful.

Moneyball is a book about Baseball, a fairly static sport compared to Football. When it boils down to it Baseball is a contest between two players the pitcher and the hitter. Football is a contest between 15 – 20 players, with a whole host of tactics thrown in.

So as somebody who collects and analyses ‘the numbers’ in Gaelic Games, this might seem like a strange thing to write. Do I think sports analytically can be applied to football & hurling? Absolutely – but we must look at the right stats not just ones that are easy to collect or that make a great headline in the papers. There are stats that managers up and down the country are placing too much emphasis on (Kickouts) and there are important stats they are ignoring (Turnovers), to give just two examples.

Stats have a place in all sports, my point is that if we always look at the wrong stats they will always be wrong. I am only starting my journey collecting stats in Football & Hurling and who know’s what we might discover. As teams constantly look for that 1 or 2% to take them over the line who can say we won’t find some value in examining the numbers?

By |November 22nd, 2011|Uncategorized|0 Comments