• Jason Wulfsohn // MSc (Med) Exercise Science

Editor’s Musings: Data Driven Tactics – Do We Put the Cart Before the Horse?

Everyone seems to be interested in match stats these days. Not just the coaches, but also school children, arm-chair refs, and more. It’s not too difficult to find some basic match stats on the internet, just pop over to ESPN’s cricinfo for example. Facts and stats allow us to back-up our arguments over social media or around the water cooler. So it’s understandable why people are interested. Sometimes the facts and stats are just plain interesting. However, moving across from the general to the specific, we who work in the realm of sport also like our facts and stats. For some, it’s their job to produce these match statistics and Key Performance Indicators (KPI’s). Dr Michele van Rooyen is just one of those people and she has written some helpful articles for those interested in sports analysis (click here).

I won’t pretend to have her level of understanding or skills when it comes to sport analysis, but I’ve been thinking a little bit about game or match stats for a while. Unfortunately, I’ve been out of the coaching game for two years now. I wasn’t coaching at a high level, but we still played to win, and I would have to make decisions about how the team would play the game. Over the years I have heard coaches justifying their game plans and tactics with data, stats, facts, or whatever you want to call it. Perhaps some of it appropriate and beneficial, but I admit that I have some concerns.

While slightly paraphrased, “70% of tries in school boy rugby come within five phases”, was the comment that got me thinking about how we use stats in planning our strategy and tactics. I remember wondering where the coach got this stat (concern no.1), when he got it (concern no.2), and then ultimately wondering whether this was even applicable to our team (concern no.3).

Concern No.1: Where do these guys get their information?

Perhaps it’s a male thing, but some guys know the game flippen well. Too well, if you ask me. I’ve been googling for match analysis data that’s freely available on the web, and I’ve been getting a few hits on basic stats, but when it comes to stuff I consider relevant, I’m coming up short. Because I’m mostly involved with rugby, I often hear stats from coaches about the Crusaders and All Blacks and how they attack from this or that field position or score the most tries from turn-overs, and so on. I’ve asked coaches where they get their information, and it seems that conversations and presentations are common sources. I sometimes consult the literature for game stats and trends. However, the problem here is that this information is, as they say in Afrikaans, “verby” (past). For instance, Vaz, van Rooyen, & Sampaio, (2010) analysed Super12 and international rugby games from 2003-2006[1], while this adds to the body of literature and the understanding of the game, a coach in 2018 should probably be looking at more current stats or trends when contemplating their tactics.

Concern No.2: Is the coach getting his/her information from an appropriate level of competition?

Never mind that your stats might be lagging a bit. Would it be appropriate for a school’s 1st XI soccer team to use the same game plan as Manchester City? Another hypothetical example; “most turnovers come from the wing in Super Rugby, therefore my u14A’s won’t play the ball to the wing.” As mentioned earlier, a coach getting information from a presentation by a professional coach might be tempted to apply it to their 1st team environment. Recently, I was privy to a presentation in which a pro coach was disseminating some fantastic information about his team’s environment and culture, but I had to constantly discern whether this or that practice or intervention would work in the school environment I currently work in. For instance, Read et al. (2017) have shown that the physical demands of schoolboy rugby are different to that of professional rugby players[2], so it stands to reason that other aspects will differ too.

Concern No.3: Should stats, facts, or KPI’s dictate game strategy and tactics?

Now we come to the meat of this little thought experiment. With regard to strategy and tactics, should we be making decisions based on information from external sources and be led by these trends or should there be more emphasis on working with a team’s strengths and style of play? For a start, some inferences from stats and/or KPI’s can be boiled down to a “common sense” approach3. More successful tackles can’t hurt your chances of winning a soccer or rugby game. Furthermore, KPI’s sometimes aren’t relevant across multiple competitions, and probably shouldn’t be universally applied and utilised[3]. This is linked to concern no.2, but is justification not to wantonly use stats and KPI’s as the primary basis for game plan. Finally, interpreting average stats and KPI’s can be tricky due to the fact that game behaviours change dependant on such factors as match location, strength of opposition, and match status[4,5]. Broad averages don’t afford contextual interpretation of game play.

At the end of the day, I’m not suggesting that data and analysis be abandoned, but perhaps the team can drive the stats and data rather than cherry-picking stats, facts, or KPI’s from external sources that may or may not be relevant to your team’s context. Ultimately, is being data driven a good idea? It depends…

  1. Vaz, L., van Rooyen, M. & Sampaio, J. Rugby game-related statistics that discrimnate between winning and losing teams in IRB and Super twelve close games. J. Sport. Sci. Med. 9, 51–55 (2010).

  2. Read, D. et al. Movement and physical demands of school and university rugby union match-play in England. BMJ Open Sport Exerc. Med. 2, e000147 (2017).

  3. Watson, N., Durbach, I., Hendricks, S. & Stewart, T. On the validity of team performance indicators in rugby union. Int. J. Perform. Anal. Sport 17, 609–621 (2017).

  4. Lago, C. The influence of match location, quality of opposition, and match status on possession strategies in professional association football. J. Sports Sci. 27, 1463–1469 (2009).

  5. Taylor, J. B., Mellalieu, S. D., James, N. & Shearer, D. A. The influence of match location, quality of opposition, and match status on technical performance in professional association football. J. Sports Sci. 26, 885–895 (2008).

#Coaching #Gameanalysis #Videoanalysis


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