By Alexander Plum of 
A study examined whether sentencing outcomes differed between Māori and NZ Europeans charged with first-time drink-driving cases, Photo: 123RF
People of Māori descent account for just a fifth of Aotearoa's population, but are over-represented at every stage of the criminal justice system.
They comprise 37 percent of people prosecuted by police, 45 percent of those convicted and 52 percent of the prison population.
Such statistics, however, aren't easily explained.
Differences in offending type only go so far. For instance, a minor assault charge can involve varying impacts on victims - and for most offences there is no objective measure of severity.
This makes it difficult to compare people charged with what appears to be the same crime.
Recent analysis from the Understanding Policing Delivery programme has already shown systemic bias at the policing stage - when all other factors are held constant, Māori were 11 percent more likely to be prosecuted than Pākehā.
Less clear is whether similar disparities occur within the courtroom. In our newly published study, we examined whether sentencing outcomes differ between Māori and NZ Europeans charged with nearly identical offences.
We focused on first-time drink-driving cases, using alcohol readings as an objective, standardised measure of offence severity.
Our core question - do Māori face a higher likelihood of a community-based sentence, instead of the more common - and least severe - outcome of a fine?
The results suggest they do.
How we compared sentencing outcomes
The Land Transport Act 1998 sets clear alcohol limits and a graduated set of penalties, from infringement notices and fines to disqualification, community-based sentences and, for repeat or serious cases, imprisonment.
For drivers aged 20 and over, offending previously began at 400 micrograms (mcg) of alcohol per litre of breath or 80 milligrams (mg) per 100ml of blood. Since 2014, lower thresholds (250mcg/50mg) have enabled police to issue infringement notices instead of prosecuting.
Drink-driving is usually a summary offence, heard in the district court and decided by a judge alone. Cases move quickly and typically result in a fine, disqualification or community-based sentence.
To build a clear picture of sentencing patterns, we use Stats NZ's Integrated Data Infrastructure, a large, linked research database containing information from government agencies, including Ministry of Justice court charges.
Between 2008-13, the Ministry of Justice also included alcohol readings - blood and breath - which can be linked to corresponding offences. Individuals can be identified consistently across datasets, such as Inland Revenue tax records or driver licence data.
Our study examined whether the highest sentence imposed was a fine or a community-based sentence, and how this differed between Māori and New Zealand European offenders.
Because virtually all drink-driving offenders plead guilty and are convicted, our focus was on sentencing, rather than conviction.
To assess the role of ethnicity, we used Stats NZ's personal details files, and included only individuals who identified solely as Māori or solely as NZ European.
To ensure the groups were directly comparable - and that any differences reflected sentencing practices, rather than offending histories or case types - we applied several restrictions.
We limited the sample to adults aged 20-69 and included only first-time offenders, with no prior convictions and whose drink-driving charge was based solely on elevated alcohol levels.
This yielded a final sample of 10,599 convictions - 2250 Māori and 8349 New Zealand European.
A clear pattern emerges
Our results showed that, despite having similar alcohol levels at the time of offending, 9.9 percent of Māori offenders received a community-based sentence, compared with 3.3 percent of NZ Europeans.
We also found Māori offenders were, on average, younger, more often parents, more often female and more likely to live in highly deprived neighbourhoods.
Our analysis controlled for offence characteristics, and a range of demographic and socioeconomic factors, but even after these adjustments, Māori remained twice as likely as NZ Europeans to receive a community-based sentence.
We also examined outcomes across district courts. Sentencing practices were shown to vary substantially, with some courts imposing community-based sentences far more frequently than others.
Importantly, we found a strong pattern - ethnic disparities were largest in courts where community-based sentences were generally more common. In other words, regional sentencing practices appeared to amplify national-level disparities.
From a policy standpoint, this is a crucial finding. It suggests regional differences in court practice can unintentionally magnify ethnic inequities.
Promoting greater consistency across courts may therefore be an important step toward a fairer justice system.
The lasting impacts
These findings matter well beyond the courtroom. First convictions and entry into the labour market often occur about the same life stage - late teens to early 20s - which co-incides with the completion of formal education.
A first job - and especially the starting salary - has a long-term influence on lifetime earnings. A conviction results in a criminal record, which employers routinely consider during background checks, a standard practice in New Zealand.
Employment law requires that these checks relate directly to job requirements and be conducted with the applicant's consent.
Nonetheless, a criminal conviction can create significant employment barriers and the severity of the sentence may intensify these challenges.
These effects are likely to be especially pronounced during economic downturns, when job vacancies are scarce and competition is high.
This story was originally published on The Conversation.
Alexander Plum - Senior Research Fellow, New Zealand Policy Research Institute, Auckland University of Technology
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