Justice Data Lab results show impact on reoffending

Langley is delighted with the Justice Data Lab results which show a positive impact of Langley’s interventions on reducing reoffending.

The Ministry of Justice introduced the Justice Data Lab in 2013 as a tool for voluntary sector organisations to measure the hard outcome results of their interventions when working in the Criminal Justice sector.

231 offenders, all who received support from Langley between 2002 and 2011, were matched against a group of offenders who did not receive support from Langley in that time period.

Langley is delighted that the findings showed that the one year proven re-offending rate* for the 231** offenders who received Langley’s support was 26%, compared with 35% for a matched control group of similar offenders.

Statistical significance testing showed that this difference in the re-offending rates was “statistically significant” meaning that there was confidence that there was a real difference in the re-offending rate for people who received Langley’s support between by between 2 and 14 percentage points.***

This underlines the fact that Langley makes a significant difference to people’s lives. While individuals are with us, we have a 2.6% reconviction rate.

The full report – including statistical clarification – can be found in the full report.

Explanatory notes – Ministry of Justice

*The one year proven re-offending rate is defined as the proportion of offenders in a cohort who commit an offence in a one year follow-up period which was proven through receipt of a court conviction, caution, reprimand or warning during the one year follow-up or in a further six month waiting period. The one year follow-up period begins when offenders leave custody, start their court sentence, or from receipt of their caution.

**231 individuals were matched from a cohort of 775 individuals, whose details were sent to the Justice Data Lab, as described on page 3 of the full report.

***The p-value for this significance test was 0.005. Statistical significance testing is described on page 9 of the full report. All results exclude any individuals who had committed sex offences because of different patterns of offending.