4 ms·
I probably should have included the outliers when analyzing overall performance but if I recall correctly they did not have a significant effect. The top analy
by youngprogrammer 9y ago
I probably should have included the outliers when analyzing overall performance but if I recall correctly they did not have a significant effect.
The top analysts were determined by the average performance from one year after their ratings have been made. This isn't the top analysts out of 50,000 it's the top out of 50 or so analyst-rating pairs. There were only 16 or so analysts in total that I looked at. This isn't an instance of survivor bias as your example states. If I were to be more rigorous I could give a statistical test for this.
- gnaritas 9y agoLooking for top performers is always invoking survivor bias. It's a classic data snooping issue where the common sense approach is exactly wrong, but it'll sell a lot of books and it'll convince people who you know what you're doing as a stock analyst when it's just random luck.
- youngprogrammer 9y agoTop 10 performers out of 16 or so analysts in the analysis is not survivor bias.
- gnaritas 9y agoSure it is, it was survivor bias when you selected the 16.