Once again, it’s time for the Major League Soccer playoffs and penalty shootout season. Changes in the playoff format to a best of three-game first round where tie games after regulation go straight to a shootout mean that a player’s penalty taking skill may be more important than ever.
To quantitatively determine the best penalty takers in the 2023 playoffs, I again turn to empirical Bayes estimation. If you want the full explanation of how this works, go read my 2021 article on this topic, or, better yet, Tuan Nguyen Doan’s work that I based this work on. In short, I gathered penalty kick information via FBRef for 863 players that have attempted more than 4 penalties in their club careers (international matches are excluded here). This was used to calculate what is known as the prior distribution - basically what you would expect a normal player’s penalty taking ability to be if you know nothing about them. As a player takes penalties, the number and conversion rate give you more information about each player that updates your prior distribution to a posterior distribution. The more penalties that a player attempts gives more confidence in our ability to determine how good they actually are at taking penalties.
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