Testing on arrest scatter gun nets some extra treatment entrants
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Testing on arrest scatter gun nets some extra treatment entrants

Testing and offering treatment before court proceedings aims to capture more drug users earlier than would be captured by waiting until later in the process. Advanced first to testing on charge with a 'trigger' offence (mainly revenue-raising crime), from April 2006 testing further advanced to the arrest stage and arrestees positive for heroin or cocaine were required to attend an assessment of their drug problems and treatment needs.

One concern is that some will not be convicted of the trigger offence yet forced to undergo testing and assessment or face conviction for refusing. Set against this is the possibility that a wider net will capture more people who benefit from treatment. Both seem to have happened.

In 2007 a Home Office study tracked the progress of positive-test arrestees in England who already had a criminal record, about 70% of those testing positive.1 Its main purpose was to compare testing on charge with the later testing on arrest regime.

Making assessment mandatory raised the proportion assessed from 67% to 82%. As a result, the proportion not already in the DIP system who went on to start structured (tier 3 or 4) treatment rose from 8% to 11%, about 400 people a month. However, they were less well 'gripped' meaning that only an extra 30 a month were retained for the 12 weeks thought important for therapeutic progress. Despite testing on arrest and mandatory assessment, fewer (8 versus 9 per month) offenders with the most prolific criminal records were retained for 12 weeks than under the earlier regime.

In pilots about half the tests were positive.2 With these new figures this suggests that 5% to 6% of tested arrestees start structured treatment who might not otherwise have done so and about 1% stay for 12 weeks. 'Might' because there was no comparison group not processed through DIP, and because as many arrestees went on to start structured treatment apparently (but not necessarily) on their own initiative as after being referred through DIP. More may have started tier 2 'treatment' – mainly ongoing contact with DIP staff, suspect the evaluators.

These gains were bought at the cost of considerable net-widening. Across both periods 30% of positive testers had no criminal record and under the later regime 15% of the rest were unconvicted in the past three years, indicating that about 40% of those identified through on-arrest testing had no recent conviction.

The evaluators' analysis confirmed that on-arrest testing captured more relatively low level offenders. On-charge testing netted an average 1932 positive tests per month. Testing on arrest raised this to 3672, suggesting that many who never get charged are now required to undergo test and assessment. 62% of the on-arrest cohort were classified as 'low crime causing' compared to 49% previously. The proportion 'high' on this scale decreased from 24% to 17%, but extended testing meant the number rose from 460 to 610 a month.

Drawing in low-level offenders seems to do little to reduce crime. The test on charge regime (only one for which data was available) identified 2172 heroin or cocaine users with no convictions for offences committed in the past six months. In the six months after encountering this regime, they committed crimes which resulted in 2492 convictions.3 Overall the conviction rate was either unchanged or increased for over half (53%) the offenders.

These less desirable outcomes were outweighed by conviction decreases concentrated among the higher rate offenders, meaning that overall the number of convicted offences fell by 26%. By (very rough) comparison, in the NTORS study of mainly voluntary treatment entrants in England there was a 24% reduction in convictions from the year before treatment started to the year after.4

In both cases it is impossible to say to what degree testing and/or treatment contributed to the changes, especially so for the DIP process whose participants were also influenced by being arrested and charged.

Though no practice recommendations were made by the evaluators, there seems a clear case for sharper targeting towards offenders with a proven record of repeated revenue-raising crime related to drug use.

1 FEATURED STUDY Skodbo S. et al. The Drug Interventions Programme (DIP): addressing drug use and offending through 'Tough Choices'. Home Office, 2007.

2 Matrix Research and Consultancy and NACRO. Evaluation of drug testing in the criminal justice system. Home Office, 2004.

3 Calculated from table 30 of reference 1.

4 Gossop M. et al. Reductions in criminal convictions after addiction treatment: 5-year follow-up. Drug and Alcohol Dependence: 2005, 79(3), p. 295-302.

Last revised 07 January 2008

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