Shots Per Goal

Shots Per Goal

A very quick post which explores the average number of shots and shots on target it takes in order to score a goal. If we assume that shots and shots on target are a better indicator of skill than the number of goals, then we can get an idea of what the score should have been for any given game. Of course this simple analysis ignores score effects which are almost certainly prevalent.

In [1]:
import league_analysis
from IPython.display import display, HTML

The following tables then show for each year the number of shots divided by the number of goals for each of the 5 leagues we are examining and the average across all 5 leagues. We then get an overall picture for all years, firstly for each league individually and then in the final row of the final table we have the overall picture which includes all the matches we have data for.

In addition, we do the same analyses, but only for all home shots/goals and all away shots/goals, since it may be that there is a difference in the number of shots taken for each goal by home and away teams.

In [2]:
for year in league_analysis.all_years:
    display(HTML('<h3>{0}</h3>'.format(year.year_name)))
    league_analysis.display_shots_per_goal_info(years=[year])
display(HTML('<h3>All Years</h3>'))
league_analysis.display_shots_per_goal_info()

1011

league shots per goal sot per goal home spg home sotpg away spg away sotpg
epl 8.888993414863593 4.866415804327375 8.500810372771475 4.716369529983792 9.426008968609866 5.073991031390134
ech 8.309271523178808 4.354304635761589 8.333333333333334 4.322695035460993 8.278614457831326 4.394578313253012
elo 7.581842279655401 3.841616964877402 7.535329341317365 3.7904191616766467 7.63946587537092 3.9050445103857565
elt 7.347941567065073 3.4156706507304118 7.307317073170732 3.4414634146341463 7.396501457725948 3.3848396501457727
spl 7.082191780821918 3.565068493150685 7.0476190476190474 3.5238095238095237 7.122676579925651 3.613382899628253
Overall 7.880589760207388 4.013447828904731 7.806291872997378 3.9801922516749197 7.973713033953998 4.055129609346477

1112

league shots per goal sot per goal home spg home sotpg away spg away sotpg
epl 9.25703564727955 5.230769230769231 9.144039735099337 5.155629139072848 9.404761904761905 5.329004329004329
ech 8.621564482029598 4.456659619450317 8.654241645244216 4.482005141388175 8.581903276131046 4.425897035881436
elo 7.751511081262592 3.9079919408999326 7.807361963190184 3.939877300613497 7.683976261127596 3.8694362017804154
elt 8.017146776406035 3.993141289437586 7.898765432098766 3.9592592592592593 8.165123456790123 4.035493827160494
spl 6.846921797004992 3.5041597337770383 7.111111111111111 3.6126984126984127 6.555944055944056 3.3846153846153846
Overall 8.196253936681584 4.2511188463451015 8.2049969897652 4.26158940397351 8.18554039099963 4.238288454444854

1213

league shots per goal sot per goal home spg home sotpg away spg away sotpg
epl 8.985888993414864 5.089369708372531 9.065878378378379 5.108108108108108 8.885350318471337 5.065817409766455
ech 7.918340026773762 4.136546184738956 7.941105769230769 4.150240384615385 7.889728096676738 4.119335347432024
elo 8.539136795903438 4.286027798098025 8.547169811320755 4.30188679245283 8.5296 4.2672
elt 7.874204946996467 3.963957597173145 7.951219512195122 3.9653401797175865 7.779874213836478 3.9622641509433962
spl 7.016051364365971 3.524879614767255 7.2373887240356085 3.599406528189911 6.755244755244755 3.437062937062937
Overall 8.146259644414625 4.2358269037235825 8.211151736745887 4.256855575868373 8.066791044776119 4.210074626865672

1314

league shots per goal sot per goal home spg home sotpg away spg away sotpg
epl 9.709125475285171 3.223384030418251 9.503344481605351 3.20066889632107 9.980176211453745 3.253303964757709
ech 10.129009762900976 3.301952580195258 10.257250945775535 3.3455233291298865 9.970358814352574 3.2480499219968797
elo 8.29938900203666 3.3380855397148674 8.337871287128714 3.339108910891089 8.25263157894737 3.336842105263158
elt 8.426026336173509 3.3446940356312935 8.379008746355685 3.3411078717201166 8.479338842975206 3.3487603305785125
spl 7.520766773162939 3.0894568690095845 7.417391304347826 3.1043478260869564 7.647686832740214 3.0711743772241995
Overall 8.943158611300204 3.283696392103472 8.935294117647059 3.290402476780186 8.95275888133031 3.2755102040816326

1415

league shots per goal sot per goal home spg home sotpg away spg away sotpg
epl 10.098461538461539 3.275897435897436 9.923214285714286 3.205357142857143 10.334939759036144 3.3710843373493975
ech 10.175033921302578 3.289009497964722 10.160736196319018 3.2625766871165642 10.192716236722307 3.3216995447647952
elo 8.15915300546448 3.3545081967213113 8.38974358974359 3.428205128205128 7.896198830409356 3.27046783625731
elt 8.502657555049355 3.3705391040242976 8.248979591836735 3.254421768707483 8.823024054982818 3.5171821305841924
spl 7.7904599659284495 3.340715502555366 7.615151515151515 3.2848484848484847 8.01556420233463 3.412451361867704
Overall 9.035585353274884 3.3269726663228467 8.993167701863355 3.293167701863354 9.088178667693493 3.3688871775125144

1516

league shots per goal sot per goal home spg home sotpg away spg away sotpg
epl 10.404040404040405 3.525252525252525 12.568181818181818 3.7954545454545454 8.672727272727272 3.309090909090909
ech 10.673758865248226 3.3191489361702127 11.86111111111111 3.611111111111111 9.434782608695652 3.0144927536231885
elo 8.662921348314606 3.4831460674157304 8.68421052631579 3.5052631578947366 8.63855421686747 3.4578313253012047
elt 7.9523809523809526 3.1746031746031744 7.5588235294117645 3.019607843137255 8.413793103448276 3.3563218390804597
spl 7.204081632653061 3.4081632653061225 6.980392156862745 3.2549019607843137 7.446808510638298 3.574468085106383
Overall 8.916312056737588 3.3631205673758866 9.228021978021978 3.39010989010989 8.583577712609971 3.334310850439883

All Years

league shots per goal sot per goal home spg home sotpg away spg away sotpg
epl 9.394321173373449 4.342421963144039 9.263018242122719 4.286567164179105 9.566217976552323 4.415544941380808
ech 9.05232869379015 3.89855460385439 9.10517408123791 3.9093326885880075 8.986810551558753 3.885191846522782
elo 8.070588235294117 3.7330213903743314 8.123435582822086 3.7479754601226993 8.00734214390602 3.7151248164464024
elt 8.009476031215161 3.6137123745819397 7.926246185147508 3.5885045778229907 8.110357583230579 3.644266337854501
spl 7.24879769156781 3.402693170888105 7.281157708210277 3.4152392203189605 7.210378681626929 3.387798036465638
Overall 8.442695893996401 3.8177981351218713 8.437659486083913 3.813304848376951 8.448884351757329 3.823319235817413

Conclusion

My take from this is that the number of shots/shots on target per goal is not affected by whether the team is playing at home or away. It does seem to be affected by which league the match is taking place in. In particular the higher the league the more shots/sots required per goal. There also seems to be year-on-year differences, but these are smaller.

A final note is that it seems to converge pretty quickly after a few matches in a given season. So I think we can safely use the shots/sots per goal from the current season on a per-league basis. We do not need to look at historical data, nor do we need to separate home from away teams.

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