An Introduction to Football Statistics

Kamil Kowalczyk is a Sports Development and Coaching Sciences graduate today he gives us an introduction to football statistics and how they can be used in the game.

There is no doubt that statistics can give a major advantage in modern day football; however, this is only the case when they are collected and applied correctly. To start off with, you need to make sure that the statistics collected are relevant for their intended use. There is no point keeping track of the number of shots if you are trying to evaluate defensive play; or measuring how far the goalkeeper has travelled. This is especially important when your resources are limited.

Which bring us nicely to the second point. You have to recognise the opportunities and limitations of your resources present to you. ideally, matches would be recorded from multiple vantage points, giving a nice view of all the action. More often than not however this is not an option; statistics can be recorded live by a single person, but they should be less detailed. If you attempt to record too many variables live, chances are the data will be inaccurate with some missing when you look away from the action to make the recording. Things like shots on/off target, corners, or even number of passes can be recorded rather easily by pretty much anyone spectating, using a smartphone. The more detail the statistics require, the more reliability of the data will suffer; for instance, with no video available, it would be very difficult to record where a shot was taken from or where it landed.

A great method of improving the reliability of data is to set out definitions (bonus points if they are academic or official ones) and rules for any event you want to record. Even the things you might think are obvious, like shots or passes, should be defined; this ensures all the data is recorded to the same standard, or it can be recorded by multiple people. For example, my dissertation had a total of 12 rules and 25 definitions I used when collecting data; it might seem like a pointless task, but it helps greatly when you just aren’t sure what to record (as long as you stick to these rules and definitions).

When using data, you have to make sure that it is applied properly and the limitations of the data are taken into consideration. I have witnessed a category 2 academy evaluate goalkeepers performance based purely on the number of saves, and the percentage of ‘successful passes’ (with no definition of what is considered a successful pass). Just noting the number of saves doesn’t begin to show the reality of the situation; things like where the shot was taken from, where it landed, and the total number of shots, should all be taken into consideration.

Finally, and most importantly, statistics lone cannot be used to evaluate a player’s performance, they are simply a tool to aid with evaluation. Media, fans, and clubs are recently all placing more importance on an individual’s numbers when judging performance; but football is a team sport, and there are aspects of performance that cannot be measured.