Are you good at picking stocks, or just lucky? How do you know? Say, for example, my job is allocating capital across the roulette wheel. My work is picking th

Are you good at picking stocks, or just lucky? How do you know? Say, for example, my job is allocating capital across the roulette wheel. My work is picking the numbers, the fruits of my labour are excess returns. Are those returns not work? What are they?