Baseball before Moneyball
In a word: stats. Baseball has statics for almost anything of relevance that happens on the field. Finance has statics like expense ratio, yield, price-to-earnings ratio, total return, alpha, beta, R-squared, Sharpe ratios, and the Greeks (delta, vega, theta, rho)… just to name a few. I suspect most of my readers are more familiar with baseball stats like batting average, on-base percentage, slugging percentage, OPS, ERA, K%, BB%, GB, and the like.
Today’s blog will start with the simple concept of batting average. In baseball batting average is the number of hits divided by the number of official at bats. Since a typical baseball player can have 400 at bats per baseball season, there is a lot of statistical significance to his batting average for one year.
In contrast, a fund manager could be said to have about 4 at bats per season — one per quarter. It would take a 100-year career to have as many “at bats” as baseball player has in one. Even if you decided to count fund performance on a monthly basis, it would take 25 years to match a baseball season’s worth of data.
The most common financial definition of batting average counts a hit as outperforming the market (say the S&P 500) over a given time period, say 3 months. An out is under-performing the market. Generally a .500 batting average is analogous to the the Mendoza line in baseball. Sadly, many fund managers and financial planners bat below .500. And often those that do exceed .500 get there by early luck… luck which generally fades (back below .500) with time.
Just like in baseball batting average is not the most useful static in finance. OPS (on base plus slugging percentage) is probably a better financial stat… if it existed. Instead financial stats like Sharpe Ratio and alpha fulfill a similar role of financial performance measurement. The problem with all these financial stats for measuring fund managers is there are simply not enough “plate appearances” to reliably measure a fund manager’s performance until his or her career is almost over! It is only after a long financial career that the difference between skill and luck can be accurately sorted out… a bit late I’d say for investors looking to pick fund or fund managers.
There is a factor other than stats that financial and baseball matter share. In a recent conversation someone mentioned that baseball is the only major sport where the player scores [directly]. In other words the runner himself (herself) scores by getting safely to home plate. Basketball, football, and hockey require an object (ball or puck) to cross a threshold. Football requires a ball + a player to score a touchdown, but a field goal does not directly require a player to fly through the uprights! Only in baseball does the player himself score a run.
This analogy can be extended to the idea that the investor herself can be the only thing that matters (that scores). At the end of the day it the investor who determines how successful she is at meeting her financial goals. The Sabermetrics of finance may help her get there, but ultimately it is the investor herself who has a winning, losing, or World-Series-Championship financial season.