Dons Data #2: Expected Goals Against (xGA)
What is the data telling us about Aberdeen's defensive strength
This is the second in a small series of posts that look at analytics metrics. The goal of this site is to try and make sense of what’s happening on the field. There’s a ton of football data out there today and a lot that is pretty hard to understand. Such metrics can help to support or the eye test, make us reassess our initial impressions and give clues to predict future outcomes. These posts will provide a simple introduction and explore each one in greater detail using Aberdeen as a framework . They’ll be available as a glossary if referenced in future game debriefs or previews.
Last week I covered Expected Goals (xG). This week I look at Expected Goals Against (xGA).
xGA is pretty obviously the xG for the other team. So if you want a fuller description then please read the article linked above.
In that piece I mentioned it xGA might make for better reading for Aberdeen fans and it is true. Aberdeen currently ranked as third in the league for xGA. The Dons curently have an xGa currently of 8.6 versus an actual of 6, so they are overperforming but only slightly. This is definitely a positive and suggests our strong defensive record thus far, is sustainable.
Here’s the breakdown game by game:
Here’s the breakdown goal by goal:
There are some other points to note in terms of total xGA. Against St Mirren, Olusanya initial had an effort saved by Mitov before he tapped in. That first chance is included in their total (0.18). So essentially, the one goal conceded against the Buddies accounts for 98% of their xGA in that game. That one chance that was essentially a gift to St. Mirren in a game, according to Stephen Robinson they dominated.
Against Ross County, Ronan Hale’s missed penalty is 75% of their chance creation total. And in the Motherwell match, the second highest xGA of Aberdeen’s season, 60% of the total (0.97) came in the last two minutes plus injury time, when the Dons were defending their lead.
What does this mean?
Again, we are dealing with a small sample size, however there can be positivity taken that right now Aberdeen’s defensive frugality is sustainable. Thelin’s Elfsborg teams were noted for their defensive record and it looks like he is making a major impact on this aspect at Aberdeen already.