[Choi Min-gyu's Baseball Prism] Real Estate Statistics Are Worse Than Baseball

'On-Base Percentage Formula' Introduced in 1954 Proven Through Actual Baseball Games
Current Major League Teams Adopt WAR to Calculate Player Value as Wins
Baseball Statistics Aim to Accurately Understand Current Phenomena and Prepare for the Future
Unrealistic Housing Price Remarks by Minister... Ministry of Land, Infrastructure and Transport: "Only Representative Statistics Are Considered"
Average Sale Price Soars 20.9% as This Year's Survey Sample Size Greatly Increases

Minister of Land, Infrastructure and Transport Kim Hyun-mi is announcing support measures for housing stability for low-income and middle-class citizens on the morning of the 19th at the Government Seoul Office in Jongno-gu, Seoul. Photo by Kang Jin-hyung aymsdream@

Batting average was once the king of baseball statistics. The term symbolizing a powerful hitter is also the "3-tenths hitter." The Lee Young-min Batting Award, established in 1958, is given annually to the best high school baseball hitter. The criterion for the award is batting average. Older professional baseball fans might recall poring over personal record ranking tables in sports newspapers. Among individual batting records, batting average was the most prominently featured statistic. Even today, in the baseball yearbook published annually by the Korea Baseball Organization (KBO), batting average is placed as the first item in the batter's personal record section.

The KBO is ahead of Major League Baseball (MLB) in a few areas. One is that from its second season in 1983, it included on-base percentage as an official record eligible for awards. MLB only adopted it as an official record starting in 1984. Park Ki-chul, then a KBO statistician who passed away in 2016, led this effort. He recalled, "I was criticized for creating a useless award that would diminish the value of batting average, home runs, and RBIs."

Nowadays, batting average has long since stepped down from the throne of baseball statistics. The famous book and movie "Moneyball" tells the success story of the MLB Oakland Athletics. The protagonist, General Manager Billy Beane (played by Brad Pitt), was a devotee of on-base percentage. Following Beane's success, the belief that on-base percentage is superior to batting average became common sense in MLB.

Looking at the formulas for the two statistics clarifies why Beane prioritized on-base percentage. A batter's opportunities are recorded as plate appearances. Excluding walks, sacrifice bunts, sacrifice flies, and interference during batting and baserunning, the remaining are at-bats. Batting average is hits divided by at-bats. On-base percentage is (hits + walks) divided by (at-bats + walks + sacrifice flies). The batting average formula does not distinguish whether a hit is a single or a home run. One hit is equivalent to one walk in on-base percentage. Both formulas indicate how often a batter reaches first base given the opportunities, but on-base percentage encompasses more opportunities and a wider variety of ways to reach base.

[Image source=Yonhap News]

The on-base percentage formula was devised by Allan Roth, a statistics expert who worked for the Brooklyn Dodgers in the 1940s and 1950s. Branch Rickey, who employed Roth, first introduced the on-base percentage formula in a 1954 Life magazine article. He used National League slugger Stan Musial as an example. Musial reached base 305 times in 698 opportunities the previous year. By batting average, it was 200 times in 593 opportunities. This shows that on-base percentage reflects the reality of a batter's hitting more than batting average does. Rickey expressed this in a formula and stated, "On-base percentage is much more important than batting average."

The purpose of baseball is to win. Victory is determined by the difference between runs scored and runs allowed. Scoring runs is the batter's responsibility. Therefore, good batting statistics should more accurately represent a player's contribution to scoring. Roth and other baseball statisticians discovered a remarkable fact: a team's runs scored closely matched the product of on-base percentage and total bases (singles count as one, home runs as four). From this discovery, a method was developed to convert a batter's value into runs and then into wins. The WAR (Wins Above Replacement) metric, now adopted by most MLB teams, encompasses batting, pitching, defense, and baserunning to express a player's value in terms of wins.

As in other fields, baseball statistics aim to accurately understand current phenomena and prepare for the future. Today, professional baseball team general managers have statistical tools to assess players more precisely than general managers in soccer, basketball, or ice hockey. Batting average was discarded in this process. Of course, many teams still fail. Accurate evaluation of the present does not guarantee accurate future predictions. However, mistakes arising from misjudging the present can be reduced.

On August 31 last year, Kim Hyun-mi, then Minister of Land, Infrastructure and Transport, made a surprising statement at the National Assembly Land, Infrastructure and Transport Committee. According to the minutes, Song Eon-seok, a member of the People Power Party, asked, "In the nationwide housing price trend survey compiled by the Korea Real Estate Board, the Seoul apartment sales transaction price index rose by 40.9%, the average sales price by 44.7%, and the median sales price by 42.7%. Have you ever been briefed on these statistics?" Minister Kim replied, "No. This is the first time I am seeing them."

Minister of Land, Infrastructure and Transport Kim Hyun-mi is attending the full meeting of the National Assembly Land, Infrastructure and Transport Committee held at the National Assembly on the 30th, responding to questions from lawmakers. Photo by Yoon Dong-joo doso7@

Earlier in July, Minister Kim cited the Korea Real Estate Board's sales price index at the Land, Infrastructure and Transport Committee, stating, "Seoul apartment prices rose 14% and housing prices rose 11.3% over three years." This statement was criticized for not matching reality.

At that time, Minister Kim explained, "Although it differs from public perception, as minister I have to refer to nationally certified statistics." However, it was revealed in the August meeting that she had not even been properly briefed on statistics compiled by the same Real Estate Board. After the meeting, the Ministry of Land, Infrastructure and Transport spokesperson explained, "Only representative statistics are reported to the minister." Yet the statistics reported to the minister failed to properly reflect reality.

Starting in July this year, the Real Estate Board significantly increased the sample size for housing price statistics surveys. The monthly survey sample expanded from 17,190 households to 35,000 households, and the weekly survey from 9,400 households to 32,000 households. As a result, the average sales price surged by a staggering 20.9% in just one month. This is evidence that previous statistics did not accurately reflect reality. Without proper problem identification, effective measures cannot be implemented. One can only say it is "worse than professional baseball."

Director, Korea Baseball Society