14,000 football results analysed in python

I looked into results from leading leagues over the period 2016 to 2023 to determine (1) how big is home advantage and does it vary by league and (2) how good a predictor is xg.

My analysis of xg versus actual goals showed a strong correlation (but not perfect), so over time the two should track each other... of course that doesn't mean it converges for individual teams in an individual season!

The average benefit across all leagues is 0.33 goals. In a game of small margins, that's huge...

So, back to home advantage...the Australian A-league is most competitive, with only one team averaging more than 0.5 goals scored per home match than conceded.

Meanwhile, the MLS really stands out as an outlier, with 4 teams scoring an average of over a goal a match at home.

Which brings me to St Louis - a team which was established in 2019 and had only one season in my sample (2023), their first in the Western Conference which they won comfortably (when does a team ever get promoted and win a league comfortably!).
As a result the average home winning margin for St Louis is almost 1.8...