Luck or Skill: updated chart

With big thanks to Ben Mayhew of the excellent experimental361.com for alerting me to the errors in the skill vs luck chart in my last post.

I re-ran the numbers and got a much more normal looking chart, which I have put below. 

As PDO is mean-reverting you would expect Ghana and Ivory Coast to become luckier and the teams with PDO above 1000 to become unluckier as the tournament progresses.

However, the big caveat as Ben Mayhew pointed out to me, is that these figures (PDO & SOTR) are usually traced over the course of a league season and not in a cup-tournament. Cup tournaments generally ride much more on luck due to their duration than leagues. 

So, take these figures with a pinch of salt...

Footnote 1: If you recall, PDO is a measure of a team's luck. The higher the figure, the higher the luck - the logic goes. A team's PDO consists of its Shot percentage + its Save percentage. There are excellent summaries on PDO on James Grayson's blog (here) specifically about football and a comprehensive explanation of the measurement's origins in Ice Hockey here.

Footnote 2: The whoscored.com do not perfectly add up: shots on-target for add up to 177, whereas the shots on-target against add up to 173. No biggie, but it means no team sits on the 1000 line for PDO, as it is supposed to.