Think about this very simple question: why do better teams win football matches?
Obviously because they score more goals than weaker teams.
This bears down to two factors involved in goal scoring: creating shots and converting shots. And, of course, to the defensive equivalent: preventing shots and saving shots.
TSR, or Total Shots Ratio, is one of the most useful analytical tools for understanding the improvement or regression in a particular team.
So what is analysed in TSR? The Total Shots Ratio is the number of shots that a team takes in any one game, divided by the total number of shots in that game.
Essentially, it provides the percentage of shots that a team takes against the number they concede. It’s something that the stats community in Ice Hockey have known for years; more positive movements and less negative movements make for a successful side.
Why is this important? It may sound simplistic, but football is about scoring more goals than you allow your opponents. Do this and you tend to win games.
Taking more shots than your opponents over a number of matches suggests not only that a team were in the final third (shooting positions) more often, but that they were fashioning more opportunities and having more possession in dangerous areas, whilst restricting those same opportunities for their opponents.
Of course, in a single game it’s quite possible that a side scores with their only chance of the game, while their opponents fail to do so from umpteen chances at the opposite end, but over a number of games that evens out. The best teams create chances and restrict opponents, while the worst teams give away lots of chances and fail to create very often.
As an example, Team A takes 15 shots during a game, while their opponents, Team B, take just five. From that game, Team A has a TSR of 0.75, Team B has a TSR of 0.25.
The important point about TSR is highly predictive of future performance. For better teams it is higher, worse teams are lower and shows a strong correlation to their points total over a season.
As a stand-alone figure it doesn’t reveal much. However, over a number of matches it starts to point towards the teams that are both more creative and more defensively sound, when we get the rolling average across all of their matches.
As an example of how this works, we can use the differing philosophies from two of the world’s greats. Let’s break out the big guns.
Barcelona haven’t tended to take a huge number of shots relative to their dominance of games, as their philosophy revolves around creating opportunities in which the odds are firmly in the favour of the attacking player.
As of January 8, they’ve taken 302 in the league this season. However, they concede so few opportunities by virtue of their possession game (160), that they have a high TSR of 0.66.
Real Madrid take more shots, 364 to be precise, because their philosophy is less patient, they have more players who want to hit the ball from all angles, and they have always held the “you score four, we’ll score five” belief.
Defending is far less a priority than threatening the opposition, hence why opponents have taken 224 shots against them. Real Madrid’s TSR this season is 0.61.
In short, you improve your TSR, and in all likelihood your season, by taking more shots, and/or restricting opportunities of opponents.
The 2015/16 table showed that Reading, Huddersfield and Blackburn were all under performing, whilst Middlesbrough, Hull and Derby were performing as expected. The biggest question mark was Burnley who seemed to be over performing based on their TSR rating.
Middlesbrough’s rating was above average but is high due to the fact the defence restricts the opposition rather than their attacking prowess, if this could be addressed in the transfer window it would be a formidable combination of defence and attack.