Sabermetrics 2: Pythagorean Expectations and the KBO

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Does a team in first place really deserve to be in first place? Are they that competent, or are they simply lucky? 

A bonehead play from the other team that could have scored the winning run, a lucky bounce on an otherwise easy play at short…As an ardent baseball fan, I’ve seen plenty of close games decided by the fickle hands of lady luck. 

Let’s look at the infamous game 7 of the 2001 World Series between the New York Yankees and the Arizona Diamondbacks. The bottom of the 9th inning was riddled with errors and bad luck: a throwing fielding error by Rivera, a misplay at third by Brosius, and a blooper of a single to end the game.Even the most hardcore Diamondback fans must agree that the stars had aligned for their first franchise world series win. 

To reiterate, is it possible to know which teams deserve their rankings? Not recognizing hot streaks to be anomalies has proven to be costly; just this year, the San Francisco Giants held off giving up players Madison Bumgarner and Will Smith to contenders because of a mind-blowing winning streak just before the trade deadline. The team cooled off after a few weeks and settled down comfortably as a sub five-hundred team, far away from a playoff spot. Farhan Zaidi’s failure to trade future free agents for prospects will slow down the Giant’s rebuilding process for another few years. 

Luckily, sabermetrics might have an answer to this conundrum. The Pythagorean Projection is a sports analytics formula devised by Bill James to estimate the percentage of games a team “should” have won in a season.By comparing a team’s Pythagorean winning percentage to the actual winning percentage, one can evaluate which teams are either underperforming and overperforming. 

This is a side-by-side comparison of the actual rankings and the projected rankings of KBO teams in 2019(as of September 28th, 2019): 

Winning %Actual RankingsRankingProjected Rankings Wining %
61.4%SK Wyverns1Kiwoom Heroes64.8%
60.7%Doosan Bears2Doosan Bears64.1%
59.7%Kiwoon Heroes3SK Wyverns58.9%
55.7%LG Twins4NC Dinos53.6%
52.1%NC Dinos5LG Twins51.2%
49.3%KT Wiz 6KT Wiz48.4%
43.3%Kia Tigers7Kia Tigers45.7%
41.8%Samsung Lions8Samsung Lions42.2%
41.1%Hanwha Eagles9Hanwha Eagles40.8%
34.8%Lotte Giants10Lotte Giants36.8%

From here, we can observe that most of the teams retain their rankings from the Pythagorean Projection; specifically, we can see that the bottom five teams really deserved to miss out on a playoff spot. 

However, we can also see that the Kiwoon Heroes evidently underperformed, with nearly a 5% discrepancy between their actual winning percentage and their projected winning percentage. The Twins also overperformed slightly, with a 4% gap between their actual and projected winning percentages. 

The following examples seem to affirm my conviction that the Heroes will be the dark horse in this year’s playoff— if they manage to shake off some of their bad luck that plagued them this season.