More than 3 in 1,000 New Zealanders are in prison

This news item has been rather popular: ‘More than 1 in 100 American adults is in prison, report finds’. A Pew Center study shows that 1 in 99·1 adults in the US is incarcerated.
   My father pointed out that for every 100 (well, 99·1) adult people we might see Stateside, one is a crim, on the basis that there would be some released into society while others are going in. The statistic, I know, doesn’t quite hold up because we do not know the rate, at least not for the conversational topic. But for every 98·1 it would be fair to know that there is one person in jail.
   We then extrapolated this a little. For every one conviction, there might be a crim who walked free, right? The fuzz didn’t nab him or her? So, we get the possibility that of the 100, there actually might be someone who should be a crim but got away.
   Statistics like this sure make the US sound like an unsafe place.
   I then thought about our own stats. I don’t think we can be smug given that I said one is eight times more likely to be murdered in New Zealand compared with 50 years ago—and that’s accounting for the increase in population.
   A Parliamentary debate reveals that we had 8,457 in September. SPARC reckons that from the 2001 Census, there were 2,728,896 adults in New Zealand. (I couldn’t find more recent figures.) It may be safe to round that up slightly for 2008 and say there are an even 2·8 million.
   That works out to be 0·302 per cent, or 3 in 1,000 adults in New Zealand is incarcerated.
   It is argued in Parliament that 3 in 1,000 is high by our standards, as 8,457 is a figure that we apparently did not expect to reach till 2011.
   I know we cannot compare apples to apples: what is an ‘adult’? What programmes does one country have in place which sees to a lower or higher number? What is classified as ‘incarceration’? There are plenty of holes in this very quick analysis that even an amateur statistician can shoot down.
   In any case, I will be a little more careful when I visit the US later this year as this basic math indicates I am three times more likely to meet a crim on their streets than I am here.