Recently we wrote an article about using Expected Goals (xG) to predict how many goals will be scored in a football match. It caused quite a stir on our Facebook page, in a good way that is. One problem we had with it though was that after we published the article the numbers on the website we were using for the xG data changed, but that was out of our control and while we’d love to pay Opta for their xG stats, they charge astronomical amounts for that data and when you can get it for free somewhere else then what’s the point? As you know, we’re all about value at Bet Dynamo so getting something for free is optimal compared to paying £1000s for the same thing.

Using Expected Goals to Predict Goals

Anyway, not to be giving out about Opta, let’s go with a little experiment for a couple of tomorrow’s Champions League matches. Let’s us xG data as well as average goals to predict the amount of goals we’re going to see in some of the matches.

We’re going to compare three parameters here; Home xG (league data only), average goals scored at home in the league and average goals scored over this season’s Champions League matches.

We’re a bit limited by the matches we can choose. We can only use xG data from the Big Five league (England, Italy, Spain, Germany, France) as well as Russia, so we need matches where teams from those leagues are facing off against each other. Luckily we have a few; Atletico Madrid vs Lokomotiv Moscow, Bayer Leverkusen vs Juventus & Bayern Munich vs Spurs. Let’s have a look then at what we can find.

Atletico Madrid vs Lokomotiv Moscow

xG for Atletico: At home over this league season, Atletico’s xG has been as such: 2.45, 1.81, 1.72, 0.82, 1.54, 1.95, 3.05, 1.16 = 14.50 /8= 1.81

Average goals per league match: 1.25.

Goals per CL match 6 /5 = 1.20.

Let’s add these together and divide by three.

1.81 + 1.25 +1.20 = 4.26 /3= 1.42

xG for Lokomotiv: Away from home this season, Lokomotiv’s xG is as such: 0.66, 3.06, 2.35, 0.66, 1.51, 2.89, 1.18, 0.87, 0.83, 1.11. (15.12 /10) = 1.51

Average goals per away league match: 1.50.

CL goals, 4 /5 = 0.8.

1.51 + 1.50 + 0.80 = 3.81 /3 = 1.27

So we have 1.42 vs 1.27.

If we put that into a Poisson Calculator we can see some odds:

If we look over the odds we can see that Over 2.5 with the bookies is around 1.80, so there’s no value there, but with Under 2.5, the bookies have it at around 2.10, our table says it should be 2.02, so we’re getting value there.

BTTS is a massive 3.0 with the bookies, but only 1.83 on our Poisson Calculator, so that’s great value.

Bayer Leverkusen vs Juventus

xG for Bayer: 2.48, 0.94, 1.56, 1.66, 2.95, 2.13, 3.97, 3.04 (18.73 /8 = 2.34)

Average home league goals = 1.50

Goals per CL match = 5 /5 = 1

2.34 + 1.50 + 1 = 4.84 /3 = 1.61

Xg for Juventus: 1.89, 0.32, 1.88, 1.22, 3.57, 1.79, 1.21, 1.47 (13.35 /8 = 1.67)

Average away league goals = 0.88

Goals per CL match = 10 /5 = 2

1.67 + 0.88 + 2.0 = 4.55 /3 = 1.52

Let’s put this into the Poisson Calculator as we get this:

The bookies are giving around 1.75 for Over 2.5 so that’s decent value according to our Poisson Cal here, the away win and the draw are also showing value as well.

Bayern Munich vs Spurs

xG for Bayern: 2.48, 3.35, 2.92, 1.77, 2.88, 3.91, 2.25 (19.56 /7 = 2.79)

Average home league goals: 2.86

Average CL goals: 21 /5 = 4.2

2.79 + 2.86 + 4.2 = 9.85 /3 = 3.28

xG for Spurs: 0.07, 1.96, 1.34, 0.48, 1.35, 0.24, 2.21, 0.54 (8.19 /8 = 1.02)

Average away league goals: 1.38

Average CL goals: 17 /5 = 3.4

1.02 + 1.38 + 3.4 = 5.8 /3 = 1.93

Let’s put these into the Poisson Calculator, and we get:

Comparing these prices to the bookies we can see there’s value to be had. Over 2.5 goals is around 1.35, our calculator says it should be 1.12. Over 3.5 should be 1.31, the bookies have it at 1.95.

As you can see there are a few ways to get a good overall view of how many goals will be scored in a match. What we’ve not spoken about here though is team news, injuries and motivation. Bayern and Spurs are already qualified, as are Juventus so we need to look at other factors before deciding what to bet on, but these are handy tools to have at your disposal for making goal predictions.