Thursday, May 13, 2010

More on European ancestry and IQ

As a follow-up to the last post, the Add Health Study has a measure of IQ based on a vocabulary test. I calculated mean IQs for two groups: people who, on the racial question, only marked black, and people who marked both black and white. The mean for full blacks is 90.3 (n = 1,464), and it's 98.0 for the mixed group (n = 82). The difference is statistically significant.  


  1. Several different papers have also reported this, including Harris and Thomas in 2001 and Fryer and Levitt in 2005:

    "Figure 7 presents academic outcomes. Mixed race adolescents are less likely than blacks or whites to have a learning disability. Their AHPVT [Add Health IQ] scores are roughly in the middle of blacks and whites. While blacks fare .89 standard deviations worse than whites, mixed race children lag .33 standard deviations behind. On our other two achievement variables (grade point average and whether or not a student repeated a grade), mixed race adolescents are between blacks and whites but more similar to blacks."

  2. Anonymous7:33 PM

    Identification as black vs. mixed race may in part be driven by ideology rather than biology. In other words, it could very well be that some mixed people with more militant political views will choose to identify as fully black.



Meta-analysis of clinical trials: Eat walnuts

I am always looking for easy eating choices that are good for you. This new meta-analysis of 26 clinical trials looked to see if walnuts ma...