A journey into stats: core skills

For the opening part of our new section, we’ve wound back the clock a bit.

One of our respondees to the original column was kind enough to share some data from the 2016 Six Nations with us (if you remember, that was the one when hope was springing eternal with Eddie Jones as England bounced back from crashing out of their own World Cup by taking a Grand Slam).

The data gave some fairly clear pointers as to the whys and hows of England’s sweep, such as strategic usage of possession, efficiency of possession and points of competition during the match (remember Jones’ mantra that everything is a competition), many of which are aspects we’ll look at over the coming weeks and months in various contexts.

Primarily though, we wanted to address an initial assumption using stats: namely that the team which performs its core skills the best ought to be the one that wins.

Definitions first. What are the core skills actually? Fly-halves need to kick well, props need to win scrums, full-backs need to take high balls, locks need to dominate line-outs… but all these ought to be looked at as specialist skills, respective to each position. A core skill is more omnipresent, it needs to be a skill that every rugby player in every position should have to master in order to be able to simply play well.

The New Zealand model revolves around four: catch, pass, tackle and evade. But that is for individuals; for a team perspective we also think the key skill beyond those is ball retention: i.e. the ability to ruck/maul and successfully recycle a phase of possession into a new one (leaving kicking game aside). And set-pieces are, of course, a must.

Tackles and evasions are reasonably easy to spot, but the data we got was quite clear about the passing and catching: a successful pass was one which moved the ball into an area around one cubic metre in front of its intended recipient, such as any receiving player would be able to catch it while running forward without undue extra effort or exertion.

However a successful catch was the player retrieving the ball safely from the air irrespective of whether the pass was good or not. So a successful catch was not necessarily a successful pass, while a successful pass that was dropped still counted as a successful pass.

Meanwhile, evading was noted as a movement which made it near-impossible for any reasonable attempt at a tackle to be made, rather than just tackles missed or thundered through – and it was graded as a percentage of carries towards a possible tackler, which makes it somewhat lower than other skill percentages.

So, here are the core skill success rates from the matches, where the pink boxes mark the away team performing the core skills better and the blue boxes the home team:

And so… do the core skills count?

Not always passing and catching. The teams that passed the best only won 50 per cent of the time and the catching relationship was even lower.

But tackling was important. Of the three matches where the team that tackled best didn’t win, one was a draw, one showed a difference of half a per cent and the last one was the free for all when England won in Paris, in which both teams recorded tackle percentages among the lowest in the entire tournament.

Evasion success was also less relevant – only nine from fifteen matches saw the best evading teams win.

Meanwhile the team core skills, winning the set-piece and recycling, also saw only loose links between success in those and success overall: with set-pieces the teams that won their own set piece most only won ten from fifteen and in terms of recycling it was only nine.

So, admittedly too small a sample size of matches to be entirely statistically relevant, but perhaps a very clear pointer that if nothing else you or your team does is good: tackles win matches!

But collectively, the weight of performing core skills better was overwhelming. In matches where teams performed more of their core skills better, teams won 11 times, while there were another three where the core skills were matched – indeed, the only match where the better performing team did not win was the France-Italy match, where only a bizarre attempt at a drop-goal by Sergio Parisse separated the Italians from victory.

So core skills, or at least outperforming your opposition in enough of the core skills, do win matches we’d say. And tackles are the most important.

We’ll look a little more at some of the other data patterns from this in later editions, but in the meantime, we hope you’re enjoying, thanks for the responses and ideas, and keep sending them in, here!

by Lawrence Nolan