Unpacking the one stat that every Rugby Union team should covet above all else - the gainline

England and Saracens performance analyst Ross Hamilton looks at what he believes is still rugby's key statistical battleground and exactly why that is the case.

We all love rugby because of its unpredictability. It’s tense, dramatic, entertaining and we wouldn’t change it.

It does make it incredibly complicated to unpick and analyse however. If it were black and white, my job would have been significantly easier over the last 8 years.

There is no holy grail of data, no messiah of knowledge and no singular entity that explains why one team is better than another or why David beat Goliath.

That being said, everything in rugby is connected and everything can be prioritized by importance to help go towards explaining why games and championships have been won.

For me having spent my career analyzing top level rugby for Saracens and England there is one criteria that stands out above the rest.

The gainline.

The imaginary line on the pitch that every attacking team wants to cross and every defending team wants to protect.

If we take the two outstanding Premiership teams over the last few seasons; Saracens have the best gainline success this season with 53.43%. This means 1,012 of their total 1,894 carries have been over the gainline.

Exeter have the most total carries over the gainline with 1,223. Their success rate isn’t as high as Saracens say but for Exeter it’s a case of more is more and the more times they get over the gainline the more opportunities they give themselves, so even if they’re not very efficient they’re still very effective.

Very similarly if we now look at the bottom of the table; London Irish boast the lowest gainline success in the league of 43.28%. Worcester have only managed 819 carries over the gainline, the fewest this season.

We can dissect that information further and see how it affects each and every game. Looking at the best vs the worst; Saracens vs London Irish, they actually have a very similar amount of carries that get associated with the gainline (a kick receipt for example has no initial gainline to measure against). Saracens have had 1,894 total gainline carries or 95 carries per game on average.

Irish have made 1,973 total gainline carries for 99 carries per game. Saracens’ 10% higher gainline success than Irish’s then equates to 51 over the gainline carries for Saracens and 43 for Irish. If that doesn’t sound too significant then firstly trust me, it is. But secondly, 8 extra over the gainline carries (from fewer total carries) can result in 8 more try scoring opportunities. Converting even just one of those could be the difference between winning and losing at this level.

To try and describe the effect of this we would say that rugby is an invasion game and winning the gainline battle and achieving gainline success has so many positive repercussions for that team. In the simplest terms, to start, it gets you closer to the opposition try line but from here the benefits escalate. Getting over the gainline gives you ‘front foot ball’ a term often used that describes your ability as a team to play quickly whilst the defence is scrambling.

This is achieved as your support players are moving forward with momentum and can affect the breakdown much better resulting in quick ball for the scrum half, the defence at the same time now have to retreat and get around the ‘corner’ that is created by the ruck denting their flat defensive line. Defensive players initially need to defend the offload and then tight to the ruck where the first threat may be, this narrows everyone in defence and even if there is no threat the ability to ‘bounce out’ is hindered. This in turn limits line speed as they are still repositioning themselves while the ball is being played wide.

The lack of structure herein often leaves defences ‘numbers down’ with too few men to defend the oncoming attack. Each defender needs to make a decision on how to defend allowing good attackers to pick them off resulting in linebreaks and tries.

Now this scenario is unlikely to occur from one carry over the gainline but continued efforts create more and more unstructured defences giving the attacking team more opportunities to score.

As I said this is not definitive, there are so many other factors contributing to success in rugby, the conversion of these opportunities for example, that one could never say “winning the gainline will win you the game”. Similarly it would not be possible to say this for any other factor and if something like this was stated, by definition, it must be wrong.

Why then do I think the gainline is the most important factor in determining results?

Analysis of this seasons major competitions show that out of 120 Premiership games to date (post round 20) 75 of those were won by the team that won that gainline for a success rate of 63%. This number increased in the Champions Cup post quarter final stage to 46 out of the 64 games equating to a 72% win rate. One final small increase was seen during the 6 Nations with 11 out of the 15 games won at 73%.

These kind of numbers in a game of such unpredictability are incredibly strong and to my current knowledge the highest correlation to success. So the next time you’re watching a match look out for which team is winning that battle and how it impacts on the game.

Watch episode one of the Rugby Explorer with Jim Hamilton

Ex-Scotland international, Jim Hamilton, travels to Singapore to explore the city and find out more about the rugby scene in the Southeast Asian country. He meets up with the national team captain and several local players.