Jason Riley, writing at the Wall Street Journal on August 8, 2017 (“Legalizing Pot Is a Bad Way to Promote Racial Equality” https://www.wsj.com/articles/… ) "blacks commit violent crimes at seven to 10 times the rate whites do." That assertion is simply false. There is no good evidence that any racial or ethnic group is more inclined to violence or criminal activity than another, it's an assumption that's racist and wrong.

The data on which Riley bases his claim is from this 2011 report by the Bureau of Justice Statistics, analyzing data from the 2008 Uniform Crime Report:
"Blacks were disproportionately represented as both homicide victims and offenders. The victimization rate for blacks (27.8 per 100,000) was 6 times higher than the rate for whites (4.5 per 100,000). The offending rate for blacks (34.4 per 100,000) was almost 8 times higher than the rate for whites (4.5 per 100,000) (table 1)."
Homicide Trends in the United States, 1980-2008 -- Annual Rates for 2009 and 2010," Bureau of Justice Statistics, Nov. 2011.
https://www.bjs.gov/content/p…
https://www.bjs.gov/content/p…

All that says is who got arrested and charged and charged for homicide in 2008. The first problem is that in 2008, clearance rates were 45.1% for violent crimes overall and 63.6% for murder. That leaves large number of murders that are unsolved (the clearance rate for homicides in 2015 was only 61.5%.) Beyond that, the several high-profile cases around the US of individuals who had been convicted of murder only to be exonerated, often but not always due to DNA evidence, raise serious questions over the quality of that metric.

Rather than look at crimes where the perpetrator has been identified only by law enforcement, in order to reduce the possibility of bias it will be helpful to look at crimes where the individual who's been personally victimized can give a description of the person who committed the offense. Those data are collected by the Bureau of Justice Statistics through its National Crime Victimization Survey, though they have not published offender data in several years.

According to BJS, in 2008, the majority of victims of violent crimes, in most cases by wide margins, were white (2,788,600 victimizations with a white victim versus 570,550 with a black victim). White people reporting they'd been the victim of violent crimes reported that the perceived race of the offender in 67.4% of cases was white, in 15.4% of cases black, in 5.1% "other," and unknown or unavailable in 12.0%. Among black people reporting they'd been the victim of violent crimes, the reported offender in 15.9% of cases was white, in 64.7% of cases was black, in 7.3% of cases was "other", and was unknown/unavailable in 12.2%.
https://www.bjs.gov/content/p…

According to the 2014 report from the National Academy of Sciences, Engineering, and Medicine, "The Growth of Incarceration in the United States: Exploring Causes and Consequences":
"The relative involvement of blacks in violent crimes has declined significantly since the late 1980s (see Figure 2-12). From 1972 to 1980, the relative share of blacks in arrests for rape and aggravated assault fell by around one-fourth; more modest declines in their share of arrests were recorded for murder and robbery from the 1970s to the 2000s. In the 1970s, blacks accounted for about 54 percent of all homicide arrests; by the 2000s, that share had fallen below half. For robbery, blacks accounted for 55 percent of arrests in the 1970s, falling to 52 percent by the 2000s. For rape, blacks accounted for about 46 percent of all arrests in the 1970s, declining by 14 percentage points to 32 percent by the 2000s. The declining share of blacks in violent arrests also is marked for aggravated assaults, which constitute a large majority of violent serious crimes: 41 percent in the 1970s and just 33 percent in the 2000s.
"These figures show that arrests of blacks for violent crimes constitute smaller percentages of absolute national numbers that are less than half what they were 20 or 30 years ago (Tonry and Melewski, 2008). Violent crime has been falling in the United States since 1991. In absolute terms, involvement of blacks in violent crime has followed the general pattern; in relative terms, it has fallen substantially more than the overall averages. Yet even though participation of blacks in serious violent crimes has declined significantly, disparities in imprisonment between blacks and whites have not fallen by much; as noted earlier, the incarceration rate for non-Hispanic black males remains seven times that of non-Hispanic whites." pp. 59-60.
https://www.nap.edu/catalog/1…

The bottom line: the idea that African Americans commit crimes or acts of violence at a higher rate than whites is absurd. While it is true that economic deprivation and social alienation can drive criminality, those are separate issues that are unrelated to race. Jason Riley's assertion in his Wall Street Journal column that blacks commit violent crime at 7 to 10 time the rate of whites is incorrect.