Trends in each Scottish Premiership’s teams finishing rates so far

written by – Rangers Report   photo courtesy of – Getty Images

After this weekend, the updated database will only be made available to people who contribute a one-time fee of £15.  If you are interested, read more here.  

Conversion Rate & Fenwick Adjusted Conversion Rate (FenAdjCR)

Conversion Rates measure the percentage of shots that a team or player takes that are goals.  If a player takes ten shots & scores two goals…his Conversion Rate is 20%.

Fenwick Adjusted Conversion Rate subtracts blocked shots from the total.  So, if the same player had three of those ten shots blocked, then his FenAdjCR is 29%.

Conversion Rates are not normally a stat that I’ve highlighted, as I have leaned more towards using Shot Accuracy (rate of shots that are on target) & Shooting Percentage (rate of shots on target that are goals) when assessing how well a team or player has been finishing off their shots.

However, I am thinking that you can combine all of these, along with other data, to find entry points for further analysis.

Here are the Conversion Rates for each team in the Scottish Premiership:

  • Michael O’Halloran has scored half of St. Johnstone’s eight non-penalty goals this season & his Fenwick Adjusted Conversion Rate is 80%!  His scintillating start to the season has propelled the team’s high rates so far this season.  If you subtract O’Halloran from the team’s data, St. Johnstone’s FenAjdCR drops down to 20%.  Still among the best in the league, but not 32% good.
  • It’s interesting to see that Rangers have the greatest discrepancy between the rate of shots that are goals & the rate of unblocked shots that have scored.  Rangers have had 18 shots blocked, which represents 37% of their total shots.  Only Celtic has had more shots blocked (22), but given their volume of shots it’s a much smaller rate (28%).  Is this a shot selection issue, or is it a byproduct of the team facing 9-10 players behind the ball (of course, Celtic face the same issue so…maybe shot selection needs reviewing as well)?
  • It’s also interesting to see Partick so high up, given the fact they are bottom of the league table this season.  Of course, they have only generated 20 shots after four matches so shot creation is the real issue.  The bad news for Partick fans is that they have scored nearly a full goal more (0.98) goals than their Expected Goals total.  Their finishing has been quite good, possibly unsustainably good.

Which teams are primed to see their Conversion Rates change in the coming weeks?

Part of the way we can answer that is to look at each team’s actual goal record in relation to their Expected Goals.  How many more (or less) goals have teams scored than their xG totals suggest they should  be scoring.

  • Scary news for Rangers supporters is that this weekend’s opponent, Dundee, are way overdue for a bounce back in goal scoring.  Only 5% of their shots have been goals, & their Expected Goals suggest it’s not because of poor shot selection.  Only 38% of their shots have come from outside the penalty box, which is a pretty average number (six teams have taken a higher rate of shots from outside the box – with Hamilton leading the way with 50%).  38% of Dundee’s shots have been Scoring Chances, which is tied for third highest with Aberdeen (behind St. Johnstone 55% & Motherwell 40%).    Dundee is playing the right way, creating quality chances, & have been snakebitten so far.  That bad luck could continue for weeks (even months), or it may begin swaying back the other way sooner rather than later.
  • Also scary is that Celtic is last in the league on this graph.  They already lead the league in goal difference (+6) & these stats suggest they are primed for some 3-4 goal differential games in the coming weeks.  Sigh.
courtesy of Roddy Scott (SNS)

To get a better sense of what is driving team’s Conversion Rates it helps to begin with the quality of shots that team’s are getting.  Below you’ll find the correlation between the ratio of total shots that are Scoring Chances & the team’s overall Conversion Rates.

Scoring Chances?  What…are…those?

I define Scoring Chances as being:

Kicked shots that come from the red shaded area.  Headers are only included if they come from vicinity of the six yard box

  • The labels are making generalizations that could be entry points to further analysis.  The assumption is that it is usually forwards who are getting shots that are Scoring Chances, but obviously any player on the pitch can be taking shots from these areas.
  • When looking at graphs like this, it’s the outliers who demand more attention.  Teams like St. Johnstone, Motherwell, & Aberdeen are off to fantastic starts offensively.  Even though Aberdeen & Motherwell have slightly underperformed in relation to their Expected Goals – if they keep playing this way…the goals will come.
  • Conversely, if Hearts keeps playing the way it is….the goals aren’t coming.  They have three(!) Scoring Chances in four games…that’s bad.  On 17 occasions so far this season, teams have eclipsed three Scoring Chances in a single match.
  • The fact that Rangers is only up by one point on Motherwell & trail St Johnstone & Aberdeen by 5+ points is worrying.  It’s only been four matches, but Rangers need to begin performing better (& soon) or second place may become a much bigger challenge then most thought it would be this season.
  • Dundee’s Scott Allan has been one of the top players in the Premiership this season.  Dundee’s forwards?  Not so much.  Faissal El Bakhtaoui & Marcus Faber have combined for ten shots this season, only three have been Scoring Chances & none of their Scoring Chances have beaten the keeper.  As a team, only 13% of their Scoring Chances on Target have beaten the keeper for a goal.  For a comparison, 80% of Rangers Scoring Chances on target have been goals.  Both teams have created 14 Scoring Targets.  That’s enough to explain the difference of six points in the league table.

Another way to use data to explain how successful teams are in converting their shots into goals is breaking the shooting down to Shot Accuracy & Shooting Percentage (both explained earlier in the post).  When it comes to this set of data, let’s subtract blocked shots & use the Fenwick Adjusted data to see what trends come to the fore.

  • You can see that Rangers Fenwick Adjusted Conversion Rate is among the best in the league, even though they usually struggle to test the keeper.  They have the lowest Fenwick Adjusted Shot Accuracy in the league.  When they do get shots on target, they’ve been goals 75% of the time.  That rate is not sustainable.  A shooting percentage closer to 35-40% would be the norm for a good team.  So even as Rangers Shot Accuracy goes up, it’s Shooting Percentage will come down.  Getting a high volume of shots will be key for Rangers moving forward as these percentages get back to normal.
  • St Johnstone leads the league in the rate of their shots that are Scoring Chances & that translates to their high shooting rates.  Motherwell is another team with a high Scoring Chance rate & that helps explain their high Shooting Percentage.  Four of their six non-penalty goals have come from Scoring Chances.
  • Kilmarnock’s finishing has been a mess this season.  Only 39% of their shots have been on target, which is even worse considering they get the same percentage  of Scoring Chances from their total shots as Celtic does (obviously in much less volume).

The bottom line is:  there is still 32 matches left in the season.  All of these rates will fluctuate, but tend to settle in to consistent rates as the season goes on.  If teams ignore performance trends, even after four games, they may underrate how well they’ve performed offensively (Motherwell, Dundee to an extent), or overrate their performances (are Hearts even worse than their record?).

For Rangers, they have no room to be content.  While the defense has improved markedly, the attack has been underwhelming.  Rangers are averaging 1.75 goals per 90 minutes & that is right in the middle of the pack.  Their Expected Goals is only slightly less but their Conversion Rate is very difficult to gauge right now considering how bad their Shot Accuracy has been & how clinical the finishing has been when the shot is actually on target (Shooting Percentage).  The fact that they are only 6th in the league in the rate of shots that are Scoring Chances is a concern as well.

Fortunately, Rangers defense has very, very good in recent weeks & that’s going to have to continue while the attack continues to figure things out.

 

 

 

 

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