Talking of re-offending...

Today's column offers a wide selection of misquoted and misinterpreted statistics. Let's start with:

Crime is in long-term decline, down 43% since 1995, according to the British Crime Survey (BCS)

According to the Home Office, (pdf link here to Crime in England and Wales 2004/2005 -- oh, yes, by the way, it is worth noting, though Polly doesn't, that this only covers England and Wales):

Since peaking in 1995, BCS crime has fallen by 44 per cent, representing 8.5 million fewer crimes, with vehicle crime and burglary falling by over a half (both by 57%) and violent crime falling by 43 per cent during this period. [emphasis added, p.1]

But this is a minor quibble. It gets worse. Polly writes:

More criminals reoffend. The Prison Reform Trust points to official figures showing how prison overcrowding raises the reoffending rate. In 1995 56% reoffended within two years of release - now it is 67% (53% of those given community sentences reoffend).

Actually, the Home Office is quite careful to explain that they can't actually track reoffending accurately, merely reconviction. So, for example, they write in the excellent Prison statistics England and Wales 2002 (pdf link here, p.150):

Reconviction rates are the proportion of prisoners discharged from prison that are convicted on a further occasion within a given time period (usually 2 years). They only give a minimum indication of the proportion of offenders who re-offend because not all offenders who re-offend will be caught or prosecuted.

And so therefore, an improved detection rate would increase the statistic, giving the appearance of an increase in re-offending. Have detection rates improved? Well, apparently so. Polly writes about:

...improved crime detection, the best in five years.

Polly also writes that:

...courts have 40% fewer "ineffective" trials abandoned through bungling.

We're not done the courtesy of being given a time period here, so let's assume it is compared to the Public Service Agreement baseline date of June-August 2002. The figures show that in the Crown Court, ineffective trials were only 13.3% of the total in October-December 2005, compared to the baseline rate of 23.7%. This is a cut of 44% in the rate, but not to be sniffed at.

The Crown Court is only half the story, though (well, actually more like a fifth, but we'll come on to that). In the Magistrates' Courts, the rate has again fallen, but sadly only from 30.9% to 21.2% over the same time period (figures are here). This is only a 31% cut in the rate.

How to weigh the two rates? According to Criminal Statistics 2004, England and Wales (pdf link here), in 2002 434,500 people were committed for trial at the Crown Court, and in 2004 (the latest year which they cite) it was 382,000 (Table 2.6) In Magistrates' Courts, the figures were 1,925,000 and 2,023,000 respectively. If we're generous and weigh the two rates (44% and 31%) at 1:4, we get a weighted average of 34% and not 40%. Note that this is being as generous as possible. I am also ignoring the fact that the overall number of trials is increasing -- so the absolute number of ineffective trials will be falling slower than the rate -- and also that the balance between the Crown Court (with the higher rate) and the Magistrates' Court (with the lower rate) is shifting in favour of the latter, so the rate is falling slower than the crude weighted average suggests.

UPDATE: The following quote from the column has been worrying me:

How tragically revealing that half of all prisoners are completely illiterate and another 20% have a reading age under eight.

If it were true that 70% of prisoners had a reading age below eight, it would truly be a cause for urgent concern. Luckily, it's not true. According to Prison statistics England and Wales 2002, referred to above, 36.9% of admitted prisoners fall below "Level 1" -- defined as roughly "about GCSE standard" and "11 year old" (the amiguity is in the source. See table 11.4 in Prison Statistics, as well as the notes below it and the summary of Chapter 11 for the figures and quotes).

Now, of course 37% of prisoners having literacy levels below that of an 11 year old is too many (even if it is not "half of all prisoners are completely illiterate"), though note that this compares to about 16% for the population as a whole (see page 13 of Reducing Re-Offending Through Skills and Employment, HMG's Green paper on Offender Learning, available here).