Baseball Judgments

Baseball Judgments |
Why the Wall Street Journal's BOP is flawed


By Roger Weber


The Wall Street Journal seasonally publishes articles evaluating teams and players using statistics deemed by the author to be overarching and better descriptors of a team than traditional statistics.


To evaluate baseball players, the Journal has introduced BOP, which is essentially a measure of total bases acquired divided by the number of plate appearances. Before I became a serious student of the game and before I started reading the Journal I felt such a measure would be the ultimate tool. But Palmer’s Linear Weights formula, while not perfect, should obliterate such a thought.


Conceptually we must ask “Is it more valuable for a player to hit a home run once in every four times he comes to the plate and make out the rest of the time or to hit a single every time he comes to bat?” Under the first scenario he is ensured to score 25% of the time. Under the second example, he is never assured of scoring, but he is on base 100% of the time. Will he score 25% of the time? That depends on how good his teammates are and how good a baserunner he is. Even using the most conservative approach to calculating the answer, assuming that all hits are singles and that two singles are necessary to advance the runner home, he should score at least 27% of the times he reaches first base, which is higher than the 25% the other player scored.


While BOP is certainly a “better” statistic than, say, batting average or RBI, it has the flaw of measuring a player’s ability to accumulate bases more than his ability to get on base. If players did not have teammates to drive them in, it would work better. But the fact is that players on any base often score due to following batters’ hits. And, as many statisticians already knew, on base percentage is more valuable than slugging percentage. Thus, BOP is not the ultimate statistic. It gives a decent overview picture, but benefits power hitters too much.


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