MLS Fantasy Boss A Fantasy MLS Community
With unlimited transfers this season, match ups are more important than ever. The question is how to evaluate match ups, especially if you’re only an aspiring Armchair Analyst and not yet the real thing. The answer? Expected Goals (xG).
What are expected goals (xG)
The idea behind xG is simple. Every shot is awarded a probability of scoring based on the position on the field and the game situation, based on giant databases of shots from years and years of data. Then at the end of the game all the xGs from the individual shots are added up to generate the team’s xG for that game. This metric is a useful measure of the teams overall attacking or defending play, more so than just looking at how many goals a team has scored or allowed. If you’d like to learn more, there’s a nice video by MLS to explain further:
How to use these rankings
The rankings below use the xG metric to rank the match ups each week to help you determine which teams you should try to choose your attackers or defenders from. Each teams score is an average of their xG/g and their opponent’s xG/g separated out into offense/defense and home/away match ups. The game by game xG numbers are taken from Ben Baer’s weekly xG article.
Columns 4 and 5 use data from the entire season, taking the average of the home offense xG and away defense xG and vice versa. Columns 6 and 7 are new “form” rankings. In this case the “form” looks at just the last 3 games of each type, either home or away and uses these to recompute the rankings. While these numbers are reflective of current form, they also suffer from a small sample size, so use them with some degree of caution. To try to minimize this, columns 8 and 9 are the average of the form and season xG scores. For reference, the average match up on the season has an offensive and defensive xG/xG allowed of 1.25 xG/g. So offensive scores higher than 1.25 and defensive scores lower than 1.25 are better than average match ups.
Are you guys not posting your team any more? With the “every week is a wild card week” approach MLS took this year, I basically copy 90% of what you are doing and just change the odd player based on my gut feeling for the GW or if I really disagree with you.
That’s a different author, he just had a baby and his articles should be returning in a few weeks.
Ah, thanks. I definitely know where he’s coming from!