Premier league just finished yesterday. Interested to replicate this and this, I decided to write the code to predict who’s gonna be the PL champion next season. I’ve made a minor modification by making home advantage wasn’t defined as constant. The motivation is because Arsenal was so strong at Emirates and Liverpool was unbeaten at Anfield, but they suffer playing away.
I used three years of match data from 2015⁄2016 season to 2017⁄2018 season. Only teams that stayed in PL in those three seasons included, teams who were promoted or relegated on those years are not included. We ended up with 16 teams. I tried to only include three seasons of data to incorporate team’s development in the recent years.
In this post we tried to measure the strength of teams by their score against others. We have match score for 16 teams match for three seasons where they played each other twice in a season. We will use this score to measure the strength of a team against each other.
The observed goal counts is expressed in Poisson distribution as,
where θ is the scoring intensity for g-th game for the team playing at home (j=1) or away (j=2). To obtain θ we assume the log-linear random effect model,
The intuition of θ stated above is as follows: home represents the advantage of the home team. θ for home team is defined by home advantage, home team’s attack intensity, and away team’s defense intensity. Contrarily, θ for away team is defined by away’s attack intensity and home team’s defense. The team specific effect is modelled as,
Let’s try to simulate over 2000 seasons to see which team is the strongest next year.
Attacking and Defensive Strength
These are the probabilistic estimates of attacking and defensive strength of the teams. No wonder, Manchester city is the strongest in attacking, especially with their record breaking number of goals last season. With Mahrez joining, probably they will be even stronger. Still in the same city, Manchester United is the strongest defensively, because of course, De Gea. Tottenham is on the second place for both defensive and offensive, they have Harry Kane and probably they won’t buy any player in this window. Liverpool is very strong offensively, with few additions on the defensive line they can compete with City.
Probability of Winning the League
The cityzen will most likely win the league, followed by Tottenham. Chance of either Liverpool or United winning is >15 times lower than Man City.