Monday, May 17, 2021

Do blacks and whites who grow up equally wealthy end up with the same mean IQ?

Some people argue that mean IQs for whites and blacks differ because blacks tend to come from poorer families. A black kid raised with resources equal to a white kid will have the same IQ. Is this the case? 

Using data from the General Social Survey, I calculated mean IQ for blacks, whites, and others for several ranges of father's socioeconomic index (SES): 1-2 standard deviations (sd) below average, 1 sd below average to average, average to 1 sd above average, 1-2 sds above average, and over 2 sds. The sample size is 12,016 (immigrants were excluded). Here's a graph that summarizes the results: 

Blacks and whites raised at the same SES level do not have the same mean IQs. The higher white average ranges from about 7 points among the poorest group to more than 10 points among the wealthiest group. By the way, other non-whites--mostly Hispanics--are closer to blacks than whites. 

Sunday, May 16, 2021

Who is more likely to be murdered by a black offender: a white or an Asian?

 Wilfred Reilly (@wil_da_beast630) has a discussion going on at Twitter about which race currently faces the most "systemic racism." Some people are assuming that Asians are victimized by blacks more than whites are. Two sources of data are not very helpful here: hate crimes and victimization data from the National Crime Victimization Survey. Hate crimes are a tiny drop in the bucket of all violence, and you don't see NCVS tables with Asian victims by race of offender. (Let me know if I've missed them.) Victim data in general indicates that Asians face low levels of victimization, which makes sense because most crime is intra-racial, and Asians have very low rates of criminal offending. 

Perhaps homicide data is the best way to go here. I looked at expanded FBI homicide data and the Census to calculate rates for being murdered by a black person for two groups: 1) Whites/Hispanics, and 2) Asians/ Native Americans/Pacific Islanders. I'm afraid the FBI lumps people together that way. The rate for group 1 is 2.30 murders per 1 million population. For group 2, it's 1.44 murders per million. According to FBI data, blacks pose more of a threat to whites and Hispanics than Asians plus. 

Monday, May 03, 2021

Which low IQ groups have low arrest rates?

DGo (@Go321) on Twitter wondered which lower IQ groups still manage to be well-behaved as groups. Criminality is a decent measure of behavior, so I looked at General Social Survey data to see which groups with low average IQs also have lower than average arrest rates: 

The percent arrested for the whole country is 12.7%. The groups listed above with an arrest rate lower than that are: Filipinos, West Indians, and Non-Spanish West Indians. And let me add that these three groups have IQ means that are not very low: 96.7, 98.8, and 95.9, respectively. 

Most lower-IQ groups have high arrest rates, as expected.

UPDATE: After checking, I see that Arabs do not have a low mean IQ: it's 102.   

Sunday, May 02, 2021

It's a clean sweep: IQ is more predictive of education, income, and job prestige than dad's social class

 Someone at Twitter, I forget now, wondered if IQ or one's social class was more important for adult success. Well, the General Social Survey can help with this. I threw in basic demographics as controls. 

Here are OLS results for income:

Looking at the betas, you can see that IQ is more strongly predictive of income than father's socioeconomic status (PASEI). Notice how race is not statistically significant when IQ is included in the model. 

And job prestige? 

IQ is much more predictive of job prestige than father's PASEI. 

The results for education should be even stronger for IQ:


The beta for IQ is much larger than for dad's social class. How far one goes in school depends much more on brains than dad's wallet (or his other influences). 

Is skin tone correlated with job prestige?

The General Social Survey rated the skin darkness of a sample of black Americans, ranging from "very dark brown" to "very lig...