xG's So Far in the EPL

By David Butler

​Expected Goals (xG) is measure that considers a team’s efforts on goal relative to the difficulty of the chance created.  Lots of information on a given shot (player positioning, distance from goal,  angles, body-part used etc.) is plugged into a statistical model which in turn produces the xG stat. High xG generally transfers to more dangerous chance creation – it might be considered as a measure of threat. 

​The first table shows the xG table for the Premier League season so far using the publically available xG statistics (understat.com) ordered by total xG.

As expected, there's a correlation between xG's and actual goals scored but this is not perfect. For example, the correlation coefficient for for Home xG and home goals so far this season is .60. (and .62 for away xG and goals). 

Team/Stat	Home xG	Away xG	Total xG
Manchester City	34.71	38.37	73.08
Liverpool	35.21	25.81	61.02
Chelsea	33.23	22.69	55.92
Manchester United	28.07	20.99	49.06
Leicester City	22.28	25.47	47.75
Everton	23.43	23.17	46.6
Wolves	22.67	21.81	44.48
Southampton	20.19	20.88	41.07
Burnley	25.83	14.56	40.39
Tottenham Hotspur	20.49	19.12	39.61
Brighton & Hove Albion	20.13	18.88	39.01
Arsenal	22.14	16.28	38.42
Watford	23.77	13.34	37.11
Sheffield United	22.66	13.33	35.99
West Ham United	19.99	14.97	34.96
Aston Villa	17.96	16.85	34.81
AFC Bournemouth	18.75	15.47	34.22
Norwich City	15.61	16.71	32.32
Crystal Palace	14.72	13.75	28.47
Newcastle United	13.48	12.41	25.89

 

The next tables consider xG (home and away) in light of actual goals scored.  My understanding of xG is that having an xG that is lower than goals translates to better than expected performance - clinical finishing perhaps. Chelsea are interesting, they are the poorest relative to expectations at home but the best on the road. 

Team/Stat	Home xG	H Goals	Home Diff
Leicester City	22.28	30	7.72
Tottenham Hotspur	20.49	27	6.51
Liverpool	35.21	40	4.79
Arsenal	22.14	26	3.86
Norwich City	15.61	19	3.39
West Ham United	19.99	23	3.01
Manchester United	28.07	29	0.93
Aston Villa	17.96	18	0.04
Newcastle United	13.48	12	-1.48
Wolves	22.67	21	-1.67
AFC Bournemouth	18.75	17	-1.75
Crystal Palace	14.72	12	-2.72
Brighton & Hove Albion	20.13	17	-3.13
Manchester City	34.71	31	-3.71
Southampton	20.19	16	-4.19
Everton	23.43	19	-4.43
Sheffield United	22.66	17	-5.66
Burnley	25.83	20	-5.83
Watford	23.77	16	-7.77
Chelsea	33.23	22	-11.23

 

Team/Stat	Away xG	A Goals	Away Diff
Chelsea	22.69	28	5.31
Crystal Palace	13.75	19	5.25
Leicester City	25.47	28	2.53
Tottenham Hotspur	19.12	20	0.88
Newcastle United	12.41	13	0.59
Liverpool	25.81	26	0.19
Sheffield United	13.33	13	-0.33
Burnley	14.56	14	-0.56
Aston Villa	16.85	16	-0.85
West Ham United	14.97	14	-0.97
Wolverhampton Wanderers	21.81	20	-1.81
Southampton	20.88	19	-1.88
Arsenal	16.28	14	-2.28
Watford	13.34	11	-2.34
Manchester City	38.37	35	-3.37
AFC Bournemouth	15.47	12	-3.47
Brighton & Hove Albion	18.88	15	-3.88
Everton	23.17	18	-5.17
Manchester United	20.99	15	-5.99
Norwich City	16.71	6	-10.71

 

​The last table considers the total – Leicester's excellent season shines through. Not only do they have a relatively high xG but also have an xG that is lower than their total goal count. Man City’s position is also interesting – Liverpool and other challengers beware, this may just be an unlucky season for City.

Team/Stat	Total xG	Total Goals	Total Diff
Leicester City	47.75	58	10.25
Tottenham Hotspur	39.61	47	7.39
Liverpool	61.02	66	4.98
Crystal Palace	28.47	31	2.53
West Ham United	34.96	37	2.04
Arsenal	38.42	40	1.58
Aston Villa	34.81	34	-0.81
Newcastle United	25.89	25	-0.89
Wolverhampton Wanderers	44.48	41	-3.48
Manchester United	49.06	44	-5.06
AFC Bournemouth	34.22	29	-5.22
Chelsea	55.92	50	-5.92
Sheffield United	35.99	30	-5.99
Southampton	41.07	35	-6.07
Burnley	40.39	34	-6.39
Brighton & Hove Albion	39.01	32	-7.01
Manchester City	73.08	66	-7.08
Norwich City	32.32	25	-7.32
Everton	46.6	37	-9.6
Watford	37.11	27	-10.11