The paradox is this. When it comes to tax, the right are keen to stress that people respond to incentives. And yet when it comes to crime they seem coy about incentives, and prefer to talk about “multiculturalism“ or genes.
The paradox is especially strong because economic theory is much clearer on the link between poverty and crime than between tax rates and tax revenue.
This is because in the case of taxes, the income and substitution effects work in opposite ways. The substitution effect causes people to prefer leisure over work when taxes rise, whilst the income effect causes them to want to work more to recoup lost income. However, with crime the two work in the same direction. The income effect causes a poor person to turn to crime to raise money, whilst the substitution effect means the unemployed have more time with which to commit crime, and lower penalties - no danger of losing one‘s job - for doing so.
Unsurprisingly, therefore, the empirical evidence is much stronger for a link between relative poverty or inequality (pdf) and crime than it is for a link between tax rates and revenues.
All this suggests an obvious reason why blacks seem to be over-represented among criminals*. Blacks are disproportionately likely to be poor, and the poor are disproportionately likely to commit crime. We’d expect, therefore, blacks to be over-represented in crime even if there were no causal link from race to crime.
From this perspective, what’s remarkable is how few blacks commit crime. There are over 800,000 blacks living in London, but in 2007 only 4435 - less than 1 in 180 - were found guilty in a crown court (table 6.4 of this pdf).
Now, I don’t say this to dismiss a role for race of culture in crime - though, remember, culture often has economic roots. For me, the claim that blacks are more likely to commit crime than others, after controlling for economic factors (and peer effects?), is a hypothesis just like any other. It’s something to be tested against evidence, not to be spouted willy-nillly.
Instead, I do so to point out that there does seem to be a blind spot on the right as well as the left. If the left is loath to accept that there are racial differences in criminal behaviour, the right seem loath to accept that poverty and inequality are causes of crime, even though the Econ 101 of which they are usually so fond predicts just this.
* I say “seem” because the data cited by Charlotte and Antonia Senior - which is taken from table 5.4a of that MoJ report - refer to arrests. But these data might tell us no more than that Constable Savage is still a serving officer.