Mapas de goles esperados (explicación aquí) de los partidos de la fecha 7 en la Primera A 2016 (Argentina):
In this blog I give probabilities for games in the Argentine Primera División, show a predicted league table based on those probabilities and give a list of bets that corresponds to the given probabilities (note: you are free to use the ‘tips’, but I am not using them myself!).
I have replicated an existing prediction model and I am optimizing it for the Argentine league. The model is the so-called pi-ratings model by Constantinou and Fenton (2013). In this article they describe a system in which they assign probabilities to match outcomes (home win, draw or away win) based on historic results.
Using this expected goals model and corresponding game maps I made a quick analysis of the games that have been played so far in the Argentine league. Expected goals are generally seen as a more reliable measure of a team’s quality than goals or shots. As there are relatively few few goals in a match there is a high variability in the conversion over a short period. Shots on the other do not tell us much either as a shot from 35 meters out is different than a tap-in.
In this previous post I described my expected goals model for the Primera División (Argentina). Here I will quickly show some first examples of the resulting game maps:
Rosario Central – Newell’s Old boys
This is an example of the xG map and corresponding information on the clásico of Rosario of last February 14th. As you can see on the pitch Rosario Central trashed their local rivales: they took a lot of shots, and the majority from very good locations.
For the last couple of months I have been (slowly) working on an expected goals model for the Argentine league and I am very happy to finally present a first version here. I will explain the basics of the model here and I will also try to show some of the underlying numbers, something I haven’t seen so much in posts from others.
For the ones that want to skip this blog and just see the results: click here.
In another blog I am keeping track of my work on a expected goals model. All variables and assumptions are largely based on other people’s models, but here I’ll discuss something I have not yet seen (or missed..): the underlying shot numbers. While working on the analysis for the bigger model I found a lot of interesting statistics on the shot conversion rate (goals/shots) per, for example, game state, number of shot in the game, time in game, and more. Where for the model I will dive deeper into the numbers and use statistical testing these are largely just descriptive tables. But no tests, no significance levels. And yes, each of the paragraphs would need a blog of its own..!
You know that situation when you leave the pitch when your team is winning 2-1? At the end of the 90 minutes the rival have turned everything around and won 2-3. Stubborn as you are you tell your manager and teammates that you DID win the game, having left the field in a winning situation.
Taking those situations into account we can calculate the effectivity of each player in his team. I did this for the Argentine Primera División. Starting simple, this is the general table of players:
River Plate and Tigre played their postponed encounter last week, so all 30 teams have now played the same amount of games again: 16. In fecha 16 Boca Juniors regained the lead of the Argentine Primera División, because San Lorenzo couldn’t beat Unión. Unión thanked Malcorra for his FIFTH free kick goal of the season. River Plate, with 4 draws in the last 5 games, meanwhile climbed to the third place after a heavy loss for Racing (0-3 at Newell’s). Los Millionarios won only 1 of their 5 encounters, strangely enough against the highest placed team of the 5 opponents (Rosario). It is a weird competition.
Due to the amount of teams (30) in the league the schedules of the different clubs have so far been rather divergent. To make those differences a bit more clear I created a few tables with some extra info.
Summing all the points of the opponents a certain team has played we can conclude that, after gameweek 16, Rosario Central, Tigre – both surprisingly in the top of the table – Banfield and Boca Juniors have had the ‘easiest’ opponents of all teams in the league. On the other hand there’s River Plate’s fixture which has been one of the toughest of all clubs.
Note: this blog was written on the 14th of March. Spoiling a part of the rest of the article: Kranevitter made it to over 12 months (32 games) without losing a game before losing the super cup against Huracán (0-1) and the superclásico against Boca Juniors (0-2). He won the Copa Sudamericana 2014 and Copa Libertadores 2015 with River Plate.
In an earlier blog post I mentioned the great Matías Kranevitter, naming him as one of the top talents from the Argentine Primera División. Kranevitter (21) is, although his name might suggest otherwise, an argentine born defensive midfielder, currently playing at Copa Sudamericana holder River Plate. River Plate had an impressive year in 2014, winning both the local championship in May and the Copa Sudamericana (Europa League equivalent) in December. The young #5 was a key player in that team. He currently goes 25 games without a loss