Shooting: comparing goalscorers

Introduction

There are a number of factors to consider when examining a player's goalscoring output. Recently, Cooper provided an excellent investigation into goalpoachers at http://www.eplindex.com/18626/poachers-top-premier-league-finishers-stats-analysis.html Most obviously, a player can only score with a shot on target, but tracking the process further back: shots on target derive from total shots, total shots derive from total touches. So the total number of goals scored by a player may be thought of as:

Goals = Touches * Shots per touch * Shot accuracy * Accurate shot efficiency

The MCFC Analytics dataset provides statistics for each of these - with each one split by location: inside or outside the box, so our goalscoring formula is written as:

G = TOB * SOB/TOB * SOTOB/SOB * GOB/SOTOB + TIB * SIB/TIB * SOTIB/SIB * GIB/SOTIB

In order to judge players equally, regardless of time played, we consider goals per 90 minutes, so TIB and TOB in the formula above must be replaced by TIB/90mins and TOB/90mins.

Method

Having calculated the 8 terms in the equation above, an individual "profile" of each player may be created, by comparing a player's performance in each metric to a common benchmark. In this case, the benchmark used is a hypothetical player whose performance for each metric is the average of the players ranked from 26 to 35 in Goals/90mins (with more than 180 minutes played). 25 to 35 is an imperfect way to simulate an "average" Premier League goalscorer,with the following very broad and unscientific assumptions: There are 20 teams in the Premier League, each has 2 "first team" strikers. 25 to 35 therefore finds the middle 50% of the second strikers in each team.

Each goalscoring factor for each striker can now be compared to this benchmark and conclusions drawn.

Benchmark goalscorer

Our benchmark goalscorer, then, has the following statistics:

Top 10 goalscorers

2011/12's top 10 goalscorers, measured by Goals/90 minutes (with a minimum of 180 minutes played) are: 
This is Part 1 of 2. In Part 2, the contribution of each factor upon a player's goalscoring output, compared with the benchmark goalscorer, will be quantified.