In these hard times, funding for the arts needs all the arguments it can muster. But it is difficult to prove that participation in arts projects – however enjoyable or enlightening - can keep criminals from reoffending.

Undaunted, The Arts Alliance today published a report by New Philanthropy Capital that attempts to quantify the benefits to offenders and society of such participation.  Production of the report, Unlocking Value, was funded by Arts Council England.

The story was picked up by the Evening Standard, the BBC, and other media outlets, and may well feature in tomorrow’s papers. The Standard and BBC stories focussed on analysis of Only Connect, a charity for prisoners, ex-offenders, and those at risk of crime. It puts on plays and other arts productions in prisons.

The headline claim is that Only Connect has cut re-offending in half, from 57.5 per cent to under 26 per cent, a remarkable result if true. There are, however, grounds for doubting the claim.

Since 2006, the report says, around 1,700 prisoners and ex-offenders have participated in theatre workshops organised by Only Connect. But the analysis covers only 95 of them who went on to perform in a theatre or other arts production, and thereby became a member of Only Connect. How typical were these 95 of offenders as a whole? They are a small fraction of all those who participated, and possibly quite untypical.

Of the 95, five had never committed an offence and 18 are still in prison, so the analysis confines itself to the other 72. Contact has been lost with 14, leaving 58, of whom 15 are known to have reoffended – a rate of 25.9 per cent. Assuming the reoffending rate is the same in the 14 lost to analysis, the total of number of reoffenders is estimated to be 19.

There is no control group, so the analysis compares this rate with the rate of reoffending for prisoners as a whole, using Ministry of Justice data and correcting for age, gender and time of release. How well this correction was done cannot be assessed, since the footnoted reference is missing, but the report claims the normal reoffending rate would be 57.5 per cent.  

It then applies this rate to all 72, concluding that without the Only Connect experience 41 would have reoffended. The difference (41 – 19) is 22

Finally it estimates the total benefit to society, assuming that the average Only Connect member would have committed seven further offences if left unexposed to the healing power of theatre. Savings to the Criminal Justice System and the annual cost of prison sentences amount, it says, to £3.2 million for these 22 individuals. The total cost of the charity in supporting  its 95 members over the period was just over £1 million.

The report therefore works out the benefit this way:

£3,216,672 ÷ £1,050,486 = £3.06

concluding that “the return on investment is £3.06 over six years”. The maths is haywire – if you divide one sum of money by another sum of money what you get is a ratio, not a third sum of money. But you can see what they are trying to say. It is not that the return on investment is £3.06, but that every pound invested returns £3.06.

The report does acknowledge the possibility that the 14 lost to analysis were lost because they have reoffended. If this is assumed, then the benefits still exceed the costs, but only by a factor of 1.4.

There are so many questionable assumptions that it’s impossible to give the findings much credence. But at least the numbers analysed are greater than in another arts project considered, Clean Break, which was able to follow up just 20 women who participated in its programme in July 2010. Another 11 were lost to analysis. Despite these low numbers, and the clear likelihood that some of the missing women had reoffended, the economic benefit is calculated at almost £500,000 against costs of just over £100,000.

The questions raised are many. Are the offenders who appeared to benefit a self-selected group ready to go straight? Are the numbers large enough to draw any conclusion at all? And what would have been the effect of other programmes spending an equivalent amount of money – over £11,000 for every Only Connect member – to discourage reoffending? Prison governors would love to have this sort of money at their disposal, but I doubt they would spend it on art or theatre.