Diamonds in the Rough: Why Miles Storey may be a sneaky target this summer

 Miles Storey

Miles Storey

written by:  @TheGersReport   

Part of the promise of analytics is the idea that you can use data to find diamonds in the rough…players who may get overlooked by the mainstream could be savvy pick-ups for teams looking to get a competitive edge.  

In my first diamonds in the rough post, I highlighted Alex Schalk & he went on to score four goals in the next four matches after the write-up was published back in March. 

Boy, did I feel smart!  

He's currently riding a six match scoreless streak....awkward.  But one thing I've noticed since his hot streak is that his shot selection has kind of gone to shit.  Which is an idea for a future post...what happens to the quality of shots taken after a player goes on a hot streak of goals?

But for now....say hello to Miles Storey.  A forward who has scored a total of two goals in over 2,000 minutes. 

That's not good...

So why highlight someone sitting on a goals per 90 average of 0.09?  Do his underlying numbers suggest a bounce back may be in the cards?

The first place I look is at a player's Expected Conversion Rate (xCR) & see how it compares to their actual Conversion Rate on unblocked shots.  Is there evidence that he's simply a victim of good ol' bad luck?

Conversion Rate is a pretty straightforward stat:  what percentage of shots end up being goals?  I like to strip away blocked shots when looking at this number.

Expected Conversion Rate simply takes Expected Goals & divides it by total shots (again I only factor in unblocked shots).  So basically, what percentage of shots should have been goals?

Miles Storey this season has an xCR of 14%, the same as Eamonn Brophy & Josh Windass.  Brophy averages 0.49 goals per 90, Windass 0.41 & Storey averages 0.09.

Their Conversion Rates on unblocked shots?  Brophy's is 17%, Windass' 14%, & Storey's is 7%.  A very cursory analysis would suggest that Brophy's goal rate is slightly inflated & due to take a dip, while Windass' strong goal scoring season is something he could easily replicate next season.  Storey?  He's kinda due for a spike in goals.

 courtesy of John Kirkby (The Sun, Glasgow)

courtesy of John Kirkby (The Sun, Glasgow)

I recently looked at the league's top goal scorers from last season & what has happened to their Shooting Percentages this season.

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Shooting Percentage (Sh%) refers to the rate of Shots on Target that end up beating the keeper for a goal.  In the above chart, you can see that nearly each & every one of the top goals per 90 players from 2016-17 saw their Sh% decline in the following season.  

Back to Storey.  This season he has scored two goals from 15 Shots on Target.  That equates to a Shooting Percentage of 0.133.  On average, 33% of Shots on Target this season have beaten the keeper.  That must mean he's due to see a bump in goals soon (or next season)...right?


To what extent is a bump (or regression) highly probable & to what extent is it only, maybe, kinda likely?

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This is why analytics can be fun.  We can go from, "who knows?" to an educated assumption based on data.  

What if we applied the basic principles of Expected Goals to Shooting Percentage?  Let's call it Expected Shooting Percentage (xSh%).  I'll explain the process later, but basically if you look at a player's Shots on Target...how many should have beaten the keeper?

Remember that Miles Storey's actual Shooting Percentage this season is 0.133, but based on the kinds of Shots on Target he generated his xSh% is 0.284.  That's more then double his actual success rate.  

The fact that his Expected Shooting Percentage suggests Storey could/should have scored on 28% of his Shots on Target, instead of 13%, means Storey may be a pretty solid candidate for seeing a spike in his goal scoring next season.

Couple that with the fact that he has scored a pretty decent rate at this level before.

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Goals per 90 in 2015-16:  0.39

 

It was Storey's output while on loan with Inverness CT that inspired Aberdeen to sign him that summer.  His Shooting Percentage that season?  0.379 

If he matched that scoring rate this season...his goals per 90 would be closer to 0.25 then 0.09.

Time for a disclaimer...that hypothetical goal rate is still pretty low & represents a below-average goal rate for forwards at this level.  So what happened this season?  

A look at his stats radar may provide some entry points:

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Oh dear...what the hell is that??  It almost looks like a giant diamond ring (see what I did there?  Diamonds in the rough??)

We should probably focus on the bad first...because the bad & the good are kind of connected.  Miles Storey really struggled to generate a high volume of shots this season.  He averaged 1.49 shots per 90, which is pretty damn low for an attacking player.  You can also see that his Expected Conversion Rate is actually very low & that's largely because he doesn't get very many Scoring Chances (kicked shots from the heart of the box & headed or kicks shots from within the six yard box).

Part of this comes from playing for a Partick Thistle team that's terrible at creating shots (only Hamilton is as bad) & they are in the bottom third of the league in total Scoring Chances.  They struggle to create quality chances & it's actually Storey who does a lot of the work to create those chances for teammates.

Miles Storey plays on a team that lacks playmakers.  In fact, you could argue that he may be the best playmaker on the team.  Below you'll find the Scoring Chance Key Passes per 90 leaders for Partick- basically which players are responsible for setting up great chances.  

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Notice that Storey is second on the team & given that he has played nearly a thousand more minutes than Woods, that rate is even more impressive. 


Storey has the 12th highest Scoring Chance Key Pass rate in the league (he averages slightly less than Ryan Christie, but more than Kieran Tierney) despite playing for a team that generates among the fewest total of Scoring Chances.  

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The Miles Storey Cheat Sheet

  1. He had a very bad year scoring goals this season
  2. His underlying numbers suggest his scoring rate will improve next season
  3. He struggles to get a high volume of shots BUT....
  4. He is actually among the best playmaking forwards in the league & I doubt most people realize that...I mean who's really watching Partick Thistle football this season?
  5. He will be cheap! If Partick don't survive the relegation battle with Livingston, there may be a big FOR SALE sign on the window & I doubt it would take much for a mid-level Premiership team to bring Storey in.
  6. He's still only 24 years old & is now entering the peak years of his career.

Some notes:

  • I mention Scoring Chances a lot & very strongly believe that they should be at the heart of any data based recruitment of attacking players.  Why?  Back in March, I posted an article that shared the following numbers:  30% of all unblocked shots in the Premiership were Scoring Chances, they accounted for 63% of the goals.  Conversion Rates for non-Scoring Chances was 8%, for Scoring Chances:  30%.  Shooting Percentages on non-Scoring Chances was 11%, for Scoring Chances:  49%.  That's why I believe teams should comb through spreadsheets looking for the players that are involved in high rates of Scoring Chances.
  • Among forwards, only Leigh Griffiths averaged more Scoring Chance Key Passes per 90 minutes this season.  Billy McKay & Alfredo Morelos rounded out the top 4.
  • Here's the post in which I first introduced Expected Conversion Rates, & here is where I used Shooting Percentages to highlight which top goal scorers are due to regress next season.
  • All other stats come from my season long tracking of Scottish Premiership data.  Next season, Modern Football will work off a unified set of stats.
  • I promised to explain how I came up with Storey's Expected Shooting Percentage.  Basically shots come in different buckets that are based on the probability they will score.  For example, a shot from outside the box is in a different bucket than one from inside the six yard box. Rather then looking at the xG for each of the shots in those buckets, I figured out the Sh% of all the shots on target from those buckets this season.  Then I applied how many shots on target Storey had from each of those buckets & that generated his xSh%.  I really, really like this stat & think it can be a very useful data point to project future output for players.