What is something you used to believe, preferably something concrete with direct or implied predictions, that you now know was dead wrong. Was your belief rational given what you knew and could know back then, or was it irrational, and why?
Edit: I feel like some of these are getting a bit glib and political. Please try to explain what false assumptions or biases were underlying your beliefs - be introspective - this is LW after all.
Race is correlated with poverty, so that's expected. Is there a strong correlation beyond that?
There seems to be, although the studies that I've found with a quick search discuss this in terms of poverty having strong predictive value even after controlling for race (which is probably a less politically charged claim.) However, there are a lot of confounders that are not easy to adjust out of such an analysis.