Monday, September 19, 2011

Explaining homicide

I just came across a Wall Street Journal article debunking a poverty and crime theory called "blocked opportunities". Puh-leese! For op-ed writers, debunking crime theories is like stealing lolipops from tots. Simple, unethical and just silly.

Take criminologists (like me) who say routine activity patterns (road networks, travel habits, bar locations) produce higher/lower crime opportunities like crime hotspots. The routine activity theory suggests crime drops by disrupting routine activities and targeting those hotspots with arrests, CPTED, dealing with prolific offenders, etc.

The most comprehensive demonstration of a routine activity approach is Britain's Crime and Disorder Act, 1998.

The Act links crime prevention accountability to municipalities, creates partnerships among relevant agencies, sets prevention goals, and uses multiple strategies to tackle crime hotspots.

Convincingly, since 1998 UK police agencies have been finalists at the International Problem Oriented Policing Award program every year but two. They've won the coveted award eight times.

Some claim routine activity goes beyond street corners to whole countries. They predict Western countries have more goods, more cash for illicit drugs, more things to steal, and will therefore have larger criminal opportunities. This results in higher crime rates than in poorer countries. Voila: poverty doesn't cause crime - routine activities do. The International Crime Victimization Survey, they say, proves it.

It doesn't.

Why? Because that is a logic error called the non sequitur. Consider this:

I constructed this graph from that same survey. It shows the US homicide rate plummeting throughout the 1990s. Canada's rate dips slightly. In the UK, where the Crime and Disorder Act has been in place for the entire period, homicide flatlines and then slightly increases.

You could say this is because crime opportunities between the three countries is worse in the UK. That is unlikely. The US has more gangs, drugs, guns and plenty of crime opportunities.

It is more likely routine activity theory just breaks down at this scale and predicts nothing.

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