Ben Goldacre, The Guardian, Saturday 7 August 2010

According to the Home Office this week, Sarah’s law – where any parent can find out if any adult in contact with their child has a record of violent or sexual crimes – has “already protected more than 60 children from abuse during its pilot“. This fact was widely reported and was the headline finding. As the Sun said: “More than 60 sickening offences were halted by Sarah’s Law during its trial”.

The number of sickening offences prevented by an intervention is a difficult thing to calculate: nobody explained where the number came from, so for my own interest I called the Home Office.

“It’s not that difficult to work out is it?” This is the Home Office telling me I’m stupid (I’m okay with that). “It’s the number of disclosures issued, how many were of sex offenders, and how many children would those offenders have had contact with.” Fair enough. This means telling a parent that someone in contact with their child had a history of abuse equated to preventing an act of abuse? Yes, they said: “Protecting that child means ensuring that offender did not have a way of having contact with that child. Therefore that child is being protected.”

Fair enough. This assumes that any such contact is itself abusive, or would definitely result in abuse. That might be correct, I don’t know.

Then I asked where the number 60 came from. I was sent to an excellent report assessing the programme written by a team of academics. Neither the number 60 nor the word sixty appear in that document.

So I contacted the lead author, Prof Kemshall, who said: “You are correct that reference to sixty children is not made in the report. As I understand it the Home Office have drawn on police data sources to quote this figure and therefore I cannot assist you further. As you will see from the report we were careful to state the limits of the methodology.”

I contacted them Home Office again. “The figure is over 60 and it comes from the number of disclosures made where there was a conviction of a sexual offence with a minor or violence against a minor. In total 21 disclosures were made specifically about registered sex offenders (RSO), a further 11 disclosures were made, for example relating to convictions for violent offending. These people had access to over 60 children.”

I’m not sure this is self-evident. The academics who wrote the report couldn’t work out where the number 60 came from, and at least two pieces have appeared trying to unpick it, both coming up with different answers to me and the Home Office. The excellently-named Conrad Quilty-Harper in the Telegraph and a promising new website called FullFact both – very reasonably – tried adding various categories of numbers from the academic report, including a figure on social worker activity which seemed to make up the numbers.

I’m not saying the figure 60 is wrong. While what it represents was probably overstated – by the Home Office and the press reports – the number itself isn’t absurd. But it does seem odd that just finding out where it came from involved so much mucking about, and it seems even odder to ignore the robust figures in a long academic report that you’ve commissioned (the scheme wasn’t cheap compared to, say, social worker salaries), and instead build your press activity around one opaque figure constructed ever so slightly on the back of an envelope.

Update 7/7/10 1pm:

I’ve just had an email from Christopher Cook, FT Education Correspondent.

He was given another completely different story by the Home Office about how they got to the number 60: “60 comes from the number of disclosures made during the pilots (21) and the number of safeguarding actions that were taken in relation to a risk of abuse (43) – this can be found on the first page under the key findings heading rds.homeoffice.gov.uk/rds/pdfs10/horr32c.pdf“.

I know it’s not the most important thing in the world but this really is a dismal game of silly buggers from the Home Office on a headline figure.

CC also pulled out this interesting paper on recidivism: “(old, relies on police records, but a starting point) called “Sexual offenders – measuring reconviction, reoffending and recidivism“. That suggests recidivism rates at about 16pc. So the ‘we sent a letter which stopped child abuse’ claim seems rather weak.”