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Lies, damned lies, and statistics - Gaelic games and match data

From initial suspicion, performance analysts like Rob Carroll are central to inter-county set-ups now


2 March 2014; The Donegal video analysis team atop a crane to record the game. Allianz Football League, Division 2, Round 3, Donegal v Monaghan, O'Donnell Park, Letterkenny, Co. Donegal. Picture credit: Oliver McVeigh / SPORTSFILE

2 March 2014; The Donegal video analysis team atop a crane to record the game. Allianz Football League, Division 2, Round 3, Donegal v Monaghan, O'Donnell Park, Letterkenny, Co. Donegal. Picture credit: Oliver McVeigh / SPORTSFILE

2 March 2014; The Donegal video analysis team atop a crane to record the game. Allianz Football League, Division 2, Round 3, Donegal v Monaghan, O'Donnell Park, Letterkenny, Co. Donegal. Picture credit: Oliver McVeigh / SPORTSFILE

"We're not far off a second bus now at this stage, that's one thing anyway," joked Liam Sheedy last year when asked about his second coming as Tipperary manager.

Sheedy was reflecting on how the game had changed in the nine years between his two stints as Tipp boss. In that time, standards of preparation had rocketed, and as such, so had the size of the back-room staff.

These days, everything up to the quality of a player's sleep is analysed but what has really exploded is the role of data analysis.

Rob Carroll has seen the evolution of that within the GAA. In the middle of the last decade, and with a Masters in Performance Analysis behind him, he was met with scepticism when he tried to show counties how collating data could inform their coaching set-ups.

In the early days, only "Dublin and a couple of northern teams" were looking to use the technology which back then was rudimentary, with an emphasis on post-match analysis.


One general package would be put together after a match and the team would be taken through it later in the week. These days it's much more in-depth.

Aided by the falling cost of the technology, and a greater acceptance of the role data analysis can play, back-room teams have upped their game and aim to get personalised feedback to players within a couple of hours of the final whistle.

Analysis has also become a key part of pre-match preparation now too. The modern-day player will be handed a dossier on opponents in terms of their preferences, and things like shot success, in a bid to find the extra edge that might tip the balance in their favour.

"You'd struggle now to try and find a county team do this with one analyst," explains Carroll, who had a spell as analyst with Kieran McGeeney's Kildare. "Some could have four or five, some will have two or three but almost every team have one at this stage.

"Now you have the opposition analysed, your own teams analysed, you'll have video clips online so that the players can access it.

"A lot of the time that will be done close enough to real time, so if you are playing in Croke Park and you are getting the bus home, it's likely there is video footage available by the time the bus gets home. So the speed of everything has picked up. In the build-up to a match, they'll be getting match reports, opposition reports to say a certain forward uses his right foot most of the time and usually shoots from this area.

"You could tell him that 'his accuracy from over here isn't as good so if we can keep him in that pocket'… that kind of stuff."

The application of the information gained has become more sophisticated too. In the early days, video analysis was often used to point out mistakes.

"Now it is used as a coaching tool rather than a surveillance system," Carroll continues. "And that's the difference, the good coaches will use it like that. They'll sit down with an iPad, one-on-one with a player and show a few clips - you don't necessarily have to hammer him in a team room.

"In Kildare, they would have done that a fair bit. You'd send clips to the back-room teams and as the players arrive, or are getting changed, you'd see the selectors going around showing a good or bad clip but just having a one-on-one chat instead."

There's no silver bullet, he stresses. No number that unlocks a team's potential.

"It's not that there's any one stat on its own is a key thing. I kept hearing at the start of this that if you win your kick-outs you win the game. That was it.

"I can't find that in the data, it's not as clear-cut as that. But the better teams, they nudge the numbers in their own favour, and they nudge every number in their own favour. And all those small bits make it."

Across professional sport, the area of data analysis is exploding. At the very cutting edge, teams are working up data models with the aim of simulating how different games might pan out in a range of different circumstances. Carroll sees some of the biggest clubs going up against the likes of Google and Microsoft competing for the relevant talent.

"It's even to the point now where teams would be experimenting with stuff where they would essentially be able to re-run the game with a different player in a different position. Now that sounds bonkers, but it would be say if we didn't play Steven Gerrard in midfield and we swap him for (N'Golo) Kante or whoever, then what happens in the game, is there extra passes or how does it change? Now whether it's reliable or valuable, we will see. But that's where teams are getting to."

These days, Carroll prepares data for the retail and pharmaceutical sectors to help them understand their business better. In his spare time, he analyses scores of games for the GAA and provides the data on which rule-change proposals are made.

Croke Park have had hundreds of games given a deep-dive analysis. In those cases, every game is analysed in minute detail which can take anywhere up to eight hours, with every time a player touches the ball and their subsequent action logged.

Inevitably, club teams are taking an interest in what analysis can tell them but they tend to lean towards overkill.

"The biggest mistake I see is people trying to do too much… you hear a lot about the scoring zone and if you have a simple printout of a blank pitch, one for you and one for the opposition, just mark where the shots are coming from and whether it's a score or not. That can be a simple win just to get an idea.

"For example, if you had 10 wides in a game and they all came from far out then the issue is where you are shooting from, not your technical shooting ability. Whereas if you get 10 wides and they are all pretty close, then it's a different type of problem. So the number is the same, it's still 10 wides, but that's where the context comes in."

From being initially being viewed with suspicion, data analysts are now part of the furniture.

"Hard sell is an understatement," Carroll says of his early interactions with county teams around 2005.

"I've been to a few places and left with my tail between my legs. The attitude was 'why would you bother with this?' It wasn't like a light switch went on in '07 or '08; it has taken a long slog by a few to keep chipping away. And it also takes a bit of a generational change too.

"You'd see now players would be as demanding on an analyst's time as a manager."