In my first post, I looked at Liverpool’s conversion and creativity measures, and noted that when it came to converting chances, Liverpool were not only still lagging behind the average for the Top 4, but also the league as a whole. But I also pointed out that Liverpool, under the new management of Brendan Rodgers, are a team in transition and that an improvement should be expected over time as the players become used to his system, and that the recent goal tally at that point, was probably showing this improvement.
I am going to look further into this and track how these measures have changed over the season. I am also going to introduce form into the measures to show how
has performed over short term periods. To give some extra context, I will also
include Liverpool’s average from the whole of
previous season, and the same for the League as an average as well as the Top 4
from last season (I have used last season as it’s a complete season with all
teams having played each other). For the form measure, I will be using a 6-game
moving average as this is what we are used to seeing in the media, it should
not give too much or little significance to individual matches, and I also
believe that over 6 games you should generally see an equal number of Home and
Away fixtures, which is not the case for other even numbered amount of games.
I’ll start by looking at shots per game. In my first post I mentioned my surprise that Liverpool had taken more shots than any other team in the top 5 leagues in
Europe, as I had been
expecting the number of shots to reduce under a more patient approach. Since
then, Liverpool still have the highest shots
per game in those leagues. This is one area Liverpool were relatively strong last
season, with an average just slightly lower than that of the Top 4. This
season the rate of shots started off more or less in line with last season up
until Game 17, in which Liverpool had 29 shots against Aston Villa, and there
was a big increase in form (the 9 shots against Chelsea
also dropped out of the 6-game average equation), since then Liverpool’s
shots per game has been at a level above what the Top 4 achieved last season,
and as we know, the highest in the top leagues in Europe.
Shooting accuracy (this excludes blocked shots, as we don’t know if they were on target or not) started off very poorly, and the season average has only recently started to creep above the level of last season. This has been significantly affected by the poor start however, as the 6-game average has been above last season’s since match 14, although it still has not quite reached the league or Top 4 average from last season yet.
Next I will look at Shot Conversion and Shots on Target Conversion (these conversion rates exclude own goals, as its not clear from the stats alone whether an own goal came from a shot or from something like a misplaced clearance). As you might expect, they follow a very similar pattern. Two things to note are that this season's Shots on Target Conversion ratio is relatively stronger than the Shot Conversion ratio when compared to last season's League and Top 4 averages, and that between match 6 and 11 it was even stronger. As I mentioned in my previous post, I think that last season Liverpool were unlucky in that a number of goalkeepers had outstanding games against them and I think the relative improvement is down, in part, to that. If we look at the peak between game 6 an 11, we see that game 6 was the 5-2 win against Norwich, in which Liverpool had 16 shots, with only 5 on target, but 4 of those were goals (there was one own goal), and 3 were from outside the area, for a massive Shots on Target Conversion of 80%. The other thing to note is that since Match 22 for Shot Conversion, and Match 20 for SOT conversion,
Liverpool have been more or less
at or above the Top 4 average from last season.
Next up is Clear Cut Chance (CCC) Conversion. For those that don’t know what a CCC is, it is one of Opta’s few subjective stats, although they don’t give a full description, it can broadly be described as a chance where the attacker is probably central to goal with only the keeper to beat, however I don’t think it should be thought of as a chance that should be scored, as statistically speaking, just under 40% of all CCCs in the Premier League are scored, so on average they are a bit harder than a 50/50. The conversion rate for CCCs is much more variable than the other conversion rates, this is because in some games there will be few or even no CCCs, which means that both very high and very low single game conversion rates are far more likely. It is clear to see however that there has been a general improvement over the season, following a start of only 2 CCCs scored in the first 8 games, and that Liverpool have been significantly more clinical at taking easier chances than they were last season.
I will now look at a measure of how creative
Liverpool have been, which is the proportion of chances that they have which are CCCs. One of the main premises of the
possession based football that Brendan Rodgers likes is that the team will be
patient and wait for good chances to score rather than take the first
opportunity to shoot. But we’ve seen, counterintuitively, that Liverpool are taking more shots, so have they been
creating better opportunities? Liverpool started the season not showing the patience that was required of them and rushing too many shots, and after that slow start, Liverpool’s season average proportion of CCCs has only just edged above last season’s in the last 2 games. However in terms of form, Liverpool
have been more creative than last season since Match 20, and around or above the
Top 4 average since Match 22. It should not be a surprise that conversion
charts have a similar shape to this one, as the easier the chance, the more likely
it is to be scored. In my view, this is the clearest indication that Rodgers’
methods, from an attacking point of view, are starting to take shape, although I still think they can often show that impatience, as this excellent forensic analysis by the Sports Analysis blog of the Swansea game shows.
The final graph is the CCCs per game, which in essence is a combination of the first graph and the last one shown. The graph has a similar shape to the one above, however due to the increase in the shots per game form from Match 15, relatively speaking, Liverpool are doing even better in this metric, and have been showing Top 4 form since Match 20.
If you were to just look at the averages of these conversion and creativity metrics so far this season, they would show somewhat of an improvement over last season, particularly in terms of conversion rates. They would not take into account the poor start to the season that Liverpool had however, or the steady improvements they have since made, or that they have consistently been showing the attacking strength of a Top 4 team for close to half the season (Match 18, the 4-0 win against Fulham, can probably be pinpointed as the game when things really started to click). It seems to me that Rodgers’ has decided to build from the front, and that he may now be close to having the team playing, at least offensively, how he would like. Of course football is about defence as well as attack, and it is
Looking ahead to the final 8 games of the season, 3 of the remaining matches are against teams from the bottom 4, with only 2 teams being higher than Liverpool, so if Liverpool can maintain their recent form (losses against West Brom and Southampton aside), then they should have a relatively good run in. One thing that could of concern though is that in the last 3 games Liverpool have had only 8, 12 and most recently 10 shots in those games, which are their worst, 4th worst and 3rd worst totals of the season respectively.
Liverpool fans will hope
that this is a short term blip rather than a downward change in form.
Data taken from www.eplindex.com
Data taken from www.eplindex.com