Lady Justice

Justice Data Lab goes from strength to strength

By James Noble 14 January 2016

At NPC we are avid supporters of the Ministry of Justice (MoJ) Justice Data Lab. This is a free service that gives organisations working with offenders access to re-offending data so they can assess the impact of their work. It’s not an overstatement to describe the Justice Data Lab as revolutionary. We’re not aware of anything quite like it in the world, and we are proud to have been involved in setting it up and continue to support the development of further Data Labs services.

Today marks another significant step forward in the Justice Data Lab’s development, through a new link to a data set that will help charities working with the most complex offenders to use the service. To explain, I’ll first provide a brief reminder of how the Justice Data Lab works and why it’s so important.

The government has data on all of us. It knows how we do at school, how much we earn, whether we use health services and whether we go to prison. Organisations working to create positive change for people would love to access some of this data to see if their work is having an effect, but the government must protect it for obvious legal and ethical reasons. The Justice Data Lab gets round this by identifying which offenders have taken part in a specific intervention and providing the organisation delivering that intervention with an aggregate re-offending rate for all service users. This means organisations get the information they need about re-offending rates, without knowing which individuals have re-offended (which is the sensitive part).

The Justice Data Lab also provides a re-offending rate for a comparison group to estimate if the intervention has made a difference compared to what would have happened anyway. This is important because re-offending rates vary significantly, so comparisons must take into account the likely rate for the particular group in question. The MoJ does this by deriving specific comparison groups for each intervention using statistics from the whole Police National Computer. The significance of this is that organisations now, at a stroke, have access to better data on their impact than ever had before, and at virtually no cost.

The first results from the Justice Data Lab were published in 2013 and since then statistics have been published every month. During this time, the methodology and outputs have been developed further, with the addition of data on frequency, severity and ‘time to’ re-offending. The latest report, published today, on re-offending rates for the Langley House Trust represents another progression because it’s the first to use Offender Assessment System (OASys) data to calculate a more accurate comparison group. OASys is a probation assessment tool used to understand the risks and needs of offenders (for example, level of mental health problems or substance misuse). Until now, organisations working with offenders with complex needs couldn’t use the Justice Data Lab, because there was no data from which to derive a suitable comparison group with similarly complex characteristics. The inclusion of the OASys data has overcome this problem and so makes the assessment of impact more accurate.

In the case of the Langley House Trust, the link to OASys data enabled the MoJ to provide a more detailed picture of the profile of its service users, according to needs such as housing, substance and alcohol use. The impact analysis showed that Langley House Trust’s work is associated with statistically significant reductions in re-offending, which reflected earlier reports from the Justice Data Lab, only this time with more confidence about the comparison group used.

We welcome this development for three key reasons:

  • It opens up the Justice Data Lab to a range of organisations working with more specialist groups of offenders.
  • It is part of the transition of the Justice Data Lab from a pilot project to a more comprehensive analytical service, capable of answering increasingly nuanced questions.
  • It demonstrates MoJ’s commendable commitment to the Justice Data Lab and will hopefully serve as reminder to other government departments just how far they are being left behind in opening up their data for the common good.

To make this evidence base more powerful we need more organisations to use the Justice Data Lab—so if you work in the criminal justice sector do try to use this fantastic resource.