The Penalty Blog

Insights, research, and analysis on football analytics

Opta Pro Forum 2018

Opta Pro Forum 2018

I finally wrote about the presentation I gave at the Opta Pro 2018 Forum....

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Opta Pro Forum 2017

Opta Pro Forum 2017

I wrote up the poster presentation I gave at the 2017 Opta Pro Forum for the Opta Pro blog looking at using machine learning to quantify footballer's decisions....

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Opta Pro Forum 2016

Opta Pro Forum 2016

With the 2017 Opta Pro Forum rapidly approaching, I thought it was about time I transcribed my presentation from the previous event....

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A Footballer Recommendation Engine

A Footballer Recommendation Engine

With the transfer window well under way I thought I'd discuss my footballer recommendation engine for identifying potential transfer targets....

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Expected Goals and Uncertainty

Expected Goals and Uncertainty

My Twitter feed seems to be increasingly taken up with discussions of Expected Goals in football yet there always seems to be something important missing from the discussion, and that's uncertainty...

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Frequency of Draws in Football

Frequency of Draws in Football

There has been some discussion and misunderstanding around the low frequency of draws in football on my Twitter feed recently so I thought I'd just give a quick recap around why the probabilities of draws are so low...

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Updated Massey Ratings

Updated Massey Ratings

Updated Massey ratings for the English Premier League showing how well teams are really doing when you account for their strength of schedule...

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Expected Goals And Support Vector Machines

Expected Goals And Support Vector Machines

I've written about expected goals on this website before but I've changed approach recently so I thought I'd write up some of the different ideas I've been playing around with...

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PlayerRatings And False Negatives

PlayerRatings And False Negatives

My last article looked at how well my PlayerRatings model predicted which young players would go on to have successful careers. This time we explore false negatives - which top players may have wrongly had low PlayerRatings in their youth...

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Backtesting PlayerRatings

Backtesting PlayerRatings

Following my last article discussing my PlayerRating model for quantifying footballers, JackIO challenged me to test the model by looking at what young players it recommended...

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PlayerRatings And Team Quality

PlayerRatings And Team Quality

My previous article introduced PlayerRatings, a mathematical model I’ve been working on over the past few months to quantify the ability of individual footballers. One of the nice characteristics of this approach is that player ratings can be aggregated together to create team...

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Massey Ratings For Football Part Two

Massey Ratings For Football Part Two

In part one I introduced Massey Ratings and how they can be used to rank football teams in a way that accounts for their strength of schedule. Next, we’ll take a look at how Massey Ratings can be extended further to look at team’s attack and defence strength separately.

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Massey Ratings For Football Part One

Massey Ratings For Football Part One

We all know the league table can lie and one of the common causes of this is strength of schedule. Take Southampton, at the time of writing they are currently second in the Premier League twelve matches in yet still haven’t played...

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Predicting Football Using R

Predicting Football Using R

I recently gave a presentation to the Manchester R Users' Group discussing how to predict football results using R. My presentation gave a brief overview of how to create a Poisson model in R and apply the Dixon and Coles adjustment to it to account for dependance in the scores.

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Expected Goals: Foot Shots Versus Headers

Expected Goals: Foot Shots Versus Headers

My last article on expected goals introduced the concept of using exponential decay to estimate the probability of scoring based on the shooter’s distance from the goal. The article received lots of feedback (thanks everyone!!), with a couple of common comments standing out th...

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Expected Goals And Exponential Decay

Expected Goals And Exponential Decay

In my last article on expected goals I showed how to incorporate the distance from goal along the Y axis into the expected goal model using Pythagoras’ Theorem. This all worked pretty well, giving us an r squared value of 0.95. However, while the r squared value was good there...

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Expected Goals: The Y Axis

Expected Goals: The Y Axis

Expected goals are one of the hot topics in the football analytics community at the moment and it’s a topic I’ve previously written a number of articles on discussing how to calculate them. If you haven’t read those pieces yet it’s probably worth taking a quick look to set the...

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Expected Goals Updated

Expected Goals Updated

When I introduced my Expected Goals model a few weeks back a number of people commented on the bump in the curve where I had included penalty shots in the data set used to fit the model...

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Actual Goals Versus Expected Goals

Actual Goals Versus Expected Goals

Since my last post about how to calculate expected goals one question has come up more than any other and that is about the correlation between expected goals and actual goals..

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Expected Goals For All

Expected Goals For All

It seems that everybody has their own expected goals models for football nowadays but they all seem to be top secret and all appear to give different results so I thought I post a quick example of one technique here to try and stimulate a bit of chat about the best way to model them.

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Comparing Players Using Cluster Analysis

Comparing Players Using Cluster Analysis

As there were a couple of presentations at the recent Opta Pro Forum talking about identifying player similarities I thought I’d give a quick example of how to do something similar using k-means cluster analysis.

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EPL 2013/2014: Football Pythagorean So Far

EPL 2013/2014: Football Pythagorean So Far

Welome back! Now that I'm no longer part of Onside Analysis I'm free to start blogging again so let's start off by taking a look at how my football Pythagorean is doing for the English Premier League so far this season.

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Anouncement

Anouncement

You may have noticed that my blogging has slowed down over the past few weeks and the reason is that I have joined Onside Analysis as a computational statistician.

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Betting With The Eastwood Index And Kelly Criterion

Betting With The Eastwood Index And Kelly Criterion

I demonstrated in my last post that the odds calculated using the Eastwood Index were slightly more accurate than the bookmakers over the course of the football season. My next goal is to work out the optimal way of using this edge to make a profit, starting off with the Kelly...

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MLS Player Salaries: 2013

MLS Player Salaries: 2013

The latest Major League Soccer (MLS) salaries were released recently by the MLS Players’ Union so I thought I would post a quick summary of the data...

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The Eastwood Index, MLS and Parity

The Eastwood Index, MLS and Parity

I showed in my last post how Major League Soccer (MLS) is a much more closely matched league than the English Premier League (EPL), with the wage cap and draft system increasing the parity between teams...

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How Much Does Luck Affect MLS?

How Much Does Luck Affect MLS?

Following my recent article for Betting Expert quantifying how large a role luck plays in the English Premier League (EPL) I thought it would be interesting to look at Major League Soccer (MLS) too...

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EI Match Predictions for the English Premier League

EI Match Predictions for the English Premier League

After last week’s international matches, domestic football is finally back so here are this weekend’s match predictions using my EI predictive model. Let’s see if it can keep up its good form and continue to beat the bookmakers!

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How Accurate Are The EI Football Predictions?

How Accurate Are The EI Football Predictions?

Unfortunately time caught up with me last week and I was unable to post any predictions from my Eastwood Index. However, since then I have been busy validating the results to see how accurate the predictions really are using the 296 matches played in the English Premier League...

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Is Brendan Rogers Improving Liverpool?

Is Brendan Rogers Improving Liverpool?

As well as using my EI Index to predict future matches, it can also be used to look back at how team’s performances have changed over time. An interesting example is Liverpool, who sacked Kenny Dalglish at the end of the 2011–2012 season to bring in Brendan Rogers from Swansea City.

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EI Match Predictions for the English Premier League

EI Match Predictions for the English Premier League

For a bit of fun, here is a trial run at predicting this weekend’s EPL matches using my EI ratings. I haven’t compared these with anyone else’s odds yet but they generally look about what I would have expected....

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Introducing the Eastwood Index

Introducing the Eastwood Index

On the whole, the Elo system works okay but it was not designed with football in mind and so there are some issues with it - for example it can only handle two distinct outcomes – winning and losing...

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Understanding Elo Ratings Part Two

Understanding Elo Ratings Part Two

Now that we understand the theory behind Elo ratings, let’s take a look at how to calculate them and how to make them more relevant to football...

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Understanding Elo Ratings

Understanding Elo Ratings

The Elo rating system was originally devised by its creator Arphad Elo as a way to calculate the average skill levels of two chess players. Although the system was created specifically for chess it has also been adapted to many other games and sports, including international f...

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Predicting Football Matches Using Shot Data Part Two

Predicting Football Matches Using Shot Data Part Two

Having found that the correlation between goals scored and shots on target was the strongest of the various shooting variables I had available to me, I decided to see how well they could predict the outcome of a football match....

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What Has Caused Dimitar Berbatov’s Recent Lack of Goals?

What Has Caused Dimitar Berbatov’s Recent Lack of Goals?

Up until week 12 of the season, Dimitar Berbatov was one of the English Premier League’s top goal scorers and goal creators. However, since then he has gone 450 minutes without registering either a goal or an assist, coinciding with Bryan Ruiz’s injury...

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Using the Pythagorean Expectation Across Leagues Wordwide

Using the Pythagorean Expectation Across Leagues Wordwide

The next stage for my Pythagorean's development is to testing whether it can be applied to leagues outside the EPL. Having one Pythagorean equation that could be used globally is preferable to having to create specific equations for each league.

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Disparity in European Football Leagues

Disparity in European Football Leagues

Having mentioned the effect disparity plays on determining the league champions in previous posts I thought it would be interesting to look at the actual levels of disparity currently present in football.

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Analysis of André Villas-Boas Vs Harry Redknapp

Analysis of André Villas-Boas Vs Harry Redknapp

Since taking over as manager of Tottenham Hotspur, André Villas-Boas has been trapped in former Spurs manager Harry Redknapp’s shadow. Every tactical decision or team selection Villas-Boas makes is seemingly compared with Redknapp’s previous achievements. And after Tottenham’s...

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The Poisson Model So Far

The Poisson Model So Far

In my last article I wrote about my experiences using the Poisson distribution to predict the outcome of football matches. The results so far have been rather disappointing so I thought I would have a look at where things were going wrong.

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Using Poisson to Predict Football Matches

Using Poisson to Predict Football Matches

The Power Of Goals recently blogged about using the Poisson distribution to predict the outcome of football matches. I have been evaluating the predictive ability of the Poisson for the English Premier League (EPL) this season so I thought I would share my experiences too.

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Influence Of Clean Sheets

Influence Of Clean Sheets

To make much sense of the statistics available for football we need to have an understanding of their context so I am planning on starting off simple by looking at baselines for various events and statistics while I build up the information required to start a mathematical model.

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Football + Mathematics

Football + Mathematics

There are plenty of analytical football blogs already out there on the internet so I thought long and hard about whether to bother with pena.lt/y..

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It's Fergie Time

It's Fergie Time

After Manchester United’s recent defeat to Tottenham, Sir Alex Ferguson was once again furious about the amount of injury time played. He even went as far as to claim the four minutes Chris Foy added was an ‘insult’.

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Hello World

Hello!! Hopefully this blog will be live soon once I have worked out how to use it…

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