The claim

“It’s important to note that black men commit nearly half of all murders in this country, which is astounding when you take into consideration the fact that they only make up 12-13 per cent of the population.” “James”, 26 November 2014

There were angry protests across America this week after a grand jury decided a white police officer should not stand trial for the killing of black teenager Michael Brown in Ferguson, Missouri.

FactCheck has already looked at the statistics on killings by law enforcement officials. Though imperfect, the official figures suggest blacks are disproportionately likely to die at the hands of police.

Several people have left comments pointing out that this is not necessarily surprising or unfair, since blacks are also disproportionately likely to be involved in violent crime in the US, thereby putting themselves in the firing line.

One reader, “James”, wrote: “It’s important to note that black men commit nearly half of all murders in this country, which is astounding when you take into consideration the fact that they only make up 12-13 per cent of the population.

“So, given this fact, does it make sense that black men are disproportionately involved in shootings with the police? Your graph is appropriately proportionate, when you take into consideration the role that the black population plays in, not just murder, but crime in general.”

“Sean” said: “If one group is more likely to be involved in that then they are more likely to be killed by the police – so they have nothing to complain about if that is the case.”

We thought we’d check these claims out.

The analysis

It’s true that around 13 per cent of Americans are black, according to the latest estimates from the US Census Bureau.

And yes, according to the Bureau of Justice Statistics, black offenders committed 52 per cent of homicides recorded in the data between 1980 and 2008. Only 45 per cent of the offenders were white. Homicide is a broader category than “murder” but let’s not split hairs.

Blacks were disproportionately likely to commit homicide and to be the victims. In 2008 the offending rate for blacks was seven times higher than for whites and the victimisation rate was six times higher.

As we found yesterday, 93 per cent of black victims were killed by blacks and 84 per cent of white victims were killed by whites.

Alternative statistics from the FBI are more up to date but include many crimes where the killer’s race is not recorded. These numbers tell a similar story.

In 2013, the FBI has black criminals carrying out 38 per cent of murders, compared to 31.1 per cent for whites. The offender’s race was “unknown” in 29.1 per cent of cases.

What about violent crime more generally? FBI arrest rates are one way into this. Over the last three years of data – 2011 to 2013 – 38.5 per cent of people arrested for murder, manslaughter, rape, robbery, and aggravated assault were black.

Clearly, these figures are problematic. We’re talking about arrests not convictions, and high black arrest rates could be taken as evidence that the police are racist.

But academics have noted that the proportion of black suspects arrested by the police tends to match closely the proportion of offenders identified as black by victims in the National Crime Victimization Survey.

This doesn’t support the idea that the police are unfairly discriminating against the black population when they make arrests.

So why are black offenders – and young black men in particular – over-represented in America’s crime statistics?

Judging from online comments, there is a wide spectrum of views on this, from unapologetic racism to militant refusal to blame the problem on anything but historic white racism.

Some criminologists think we could be simply confusing race for poverty or inequality: black people tend to offend more because they tend to be more disadvantaged, living in poorer urban areas with less access to public services, and so on.

If you control for deprivation, people of different races ought to be similarly predisposed to commit crime. Or that’s the theory, at least.

There is a lot of research in this area, but a lot of it is contradictory.

This study of violent crime in deprived neighbourhoods in Cleveland, Ohio, found that reductions in poverty led to reductions in the crime rate in exactly the same way in predominantly black and white areas, suggesting poverty, not race, is the biggest factor.

Other studies get different results.

All sociologists have suffered from the same basic problem: finding urban white communities that are as disadvantaged as the poorest black neighbourhoods, so that you can get a fair comparison.

Some thinkers play down the importance of poverty in favour of the “violent subculture theory”.

This is the idea that some black communities, for some reason, have developed cultural values that are more tolerant of crime and violence.

Some commentators on the unrest in Ferguson – mostly right-wing, though not all white – seem to favour this idea, but naturally it remains highly controversial.

The verdict

There is evidence in the official police-recorded figures that black Americans are more likely to commit certain types of crime than people of other races.

While it would be naïve to suggest that there is no racism in the US criminal justice system, victim reports don’t support the idea that this is because of mass discrimination.

Higher poverty rates among various urban black communities might explain the difference in crime rates, although the evidence is mixed.

There are few simple answers and links between crime and race are likely to remain the subject of bitter argument.