Monday, January 07, 2019

Data: The four point Flynn Effect among US blacks (but pay no attention because Taleb says IQ is crap)

According to General Social Survey (GSS) data, both whites and Mexican Americans born in the US have experienced mean IQ drops in the past decade.  Is this also true of blacks?  Here are the means by decade (N = 3,865):

Mean IQ

1970s  88.0
1980s  89.0
1990s  90.8
2000s  92.1
2010s  92.4

The 70s/80s increase was 1 point; the 80s/90s was up 1.8 points; and it was up 1.3 points for the 90s/00s.  The past decade witnessed the smallest increase of 0.3 IQ points.  The 1970s-2000s gain is impressive, but lately things seem to be slowing down.

I don't how to explain the trend but suspect that American society might expose blacks and whites (via schools, mass media, etc.) to more similar words used to test vocabularies than in the past.

The typical IQ mean you read about for black Americans is 85, but the black/white verbal IQ gap appears to be smaller: GSS data indicates that in this decade the gap is six-tenths of a standard deviation.  Notice how the black mean is a point higher than the 91.5 mean for Mex-Ams reported in a recent post.       


  1. Did you exclude African immigrants?

  2. Yes. If we include black immigrants, the mean for this decade is 92.2. Black immigrants only is 90.0.


Data: How can the LGBT suicide rate be so low in a country that is supposedly so homophobic?

In this new study of over 120,000 suicides, the authors reported that 0.5% of the suicides were LGBT.  They also cited an estimate that 4.1...