Focus of the intervention
Driving while impaired (DWI) courts are available – mainly in the USA – to deal with serious/recidivist DWI offenders.
DWI courts are modelled on drug courts, and use a stick-and-carrot approach to ensure compliance with the substance abuse treatment and intense supervision conditions imposed on the offender. These usually include random or continuous testing for alcohol abuse and attending regular court hearings.
Offenders usually serve a portion of their sentence in custody, with the rest being suspended pending successful completion of the program. Those failing to graduate from the DWI court are typically returned to custody to complete their sentence.
This narrative summarises the findings of a systematic review of five studies.
Effect – how effective is it?
There is some evidence that the intervention has reduced crime, but overall the intervention has not had a statistically significant effect on crime.
Three of the five studies reviewed reported small to medium positive effects, with offenders who went through the DWI courts being less likely to be rearrested or reconvicted for DWI and other related offences (usually over a two-year follow-up period), as compared to those undergoing standard probation. The other two studies reported no significant differences between the two groups.
The reviewers argued, however, that the lack of statistically significant findings in the latter two studies could be the result of study design flaws such as small sample sizes or contamination between the treatment and control groups (i.e., the control participants were under similar levels of intense supervision as the offenders in the DWI court group).
There were no studies for which a statistically significant negative effect (where DWI court participants reoffended at a higher rate than controls) was reported.
How strong is the evidence?
The review was sufficiently systematic that many forms of bias that could influence the conclusions of the review can be ruled out. This evidence is taken from a systematic review covering just five studies, all of which were conducted in the USA. However, the small number of studies included is a concern. So too is the fact that some of the studies reviewed still had some study design problems, as noted above.
Mechanism – how does it work?
The reviewers briefly explain how DWI courts employ an intensive, stick-and-carrot supervisory approach that ensures offenders comply with the conditions of probation (for example, treatment, intensive supervision and testing for alcohol abuse). This is expected to reduce the participants’ likelihood of reoffending.
However, this assumption was not empirically tested, as the original studies did not provide the necessary information to do so.
Moderators – in which contexts does it work best?
There was insufficient data in the primary evaluations to examine under what conditions or for what populations DWI courts might work best.
However, the review cites prior literature which identifies several variables which may influence the effectiveness of the intervention, such as:
- marital status
- educational level
- employment status
- blood alcohol content (BAC) level on arrest
- number of prior DWI arrests
- number of prior criminal arrests
- alcohol use severity
- co-morbid psychiatric disorders
Implementation – what can be said about implementing this initiative?
No implementation-related information on DWI courts is provided. The reviewers mention that only one study provided some information about the dosage or intensity of the intervention, which made it impossible to determine what components are most effective or how well the programmes were implemented in practice.
Economic considerations – how much might it cost?
The review does not mention costs (or benefits) and no formal economic analysis is provided.
Although efforts were made to ensure only high-quality studies were included in the review, some of the studies reviewed still suffered from methodological flaws, which may have affected their findings.
Future studies should aim to conduct high-quality evaluations that focus on mature DWI courts (i.e., in place for at least 2-3 years), control for the effect of possible moderators, and include an assessment of implementation.
Overall, evidence suggests that DWI Courts have no impact on crime (but some studies suggest a decrease).The reviewers caution that the evidence is not robust and that more high-quality studies should be conducted to add to the existing evidence base.
Additional information is needed regarding the possible moderating influence of certain offender characteristics and issues relating to implementation.
Marlowe, D. B., Festinger, D. S., Arabia, P. L., Croft, J. R., Patapis, N. S., & Dugosh, K. L. (2009) A systematic review of DWI court program evaluations. In D. B. Marlowe (Ed.), Drug court review, Vol. VI, Issue 2 (pp. 1-52). Alexandria: National Drug Court Institute.
Summary prepared by
This narrative was prepared by UCL Jill Dando Institute and was co-funded by the College of Policing and the Economic and Social Research Council (ESRC). ESRC grant title: 'University Consortium for Evidence-Based Crime Reduction'. Grant reference: ES/L007223/1.