Improve your Win Rate
data-science
sports-and-health
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Despite winning all season, your baseball team can disappoint in the playoffs. The Oakland Athletics played 162 games and won 60% of them, then lost the one-game wildcard playoff (again!). All probable outcomes suffer from statistical significance. If you're 60% sure your trade will succeed, that's a phenomenal edge. But if you make a single bet, you lose 4 times out of 10. And remember—you only care about the outcome realized. The Athletics went home. That's what happened. Life has a statistical sample size of 1.
So how do you capitalize on your edge? Make more bets. Play more games. In a 7-game series, a team with a 60% win rate wins the series 71% of the time. If you place 41 trades with that same edge, you come out ahead 90% of the time.
The math here is the binomial distribution. If your probability of winning a single game is p, the probability of winning at least k games out of n is:
P(X ≥ k) = Σ C(n, i) · pi · (1 − p)n − i, for i = k to n
For a 7-game series (first to 4 wins), we sum the probabilities of winning 4, 5, 6, or 7 games (n = 7, k = 4, 5, 6, 7)—which comes to 71%. But what if you want 90% confidence? Working backwards, we solve for the smallest n such that P(X > n/2) ≥ 0.90—i.e., more wins than losses. The answer is 41 trades.
This is the fundamental argument for diversification, for taking many small positions instead of one large one, for building systems that let you make the same bet repeatedly. A 60% edge sounds modest. But compounded across enough trials, it becomes nearly certain.
The catch: most people don't have enough at-bats. They make one or two big decisions—one job, one investment, one launch—and live with the outcome. The edge was real. The sample size wasn't.