Behavioural Science in the Justice Sector

Behavioural scientists based in the Justice Sector Directorate seek to understand people better so we can make our justice system work for them. The behavioural science experts, sometimes referred to as Behavioural Science Aotearoa (BSA), use evidence and research methods from social sciences to ensure policies and processes reflect the way people behave and make decisions. The team creates more accessible and culturally aware systems to improve outcomes for everyone who uses justice services in Aotearoa.

What is behavioural science?

Whether it’s supporting Police to submit documents for court, helping people stick to their bail conditions, or reducing offending in the first place, almost everything the justice sector does involves people making decisions.

We often expect people to respond in certain ways to laws, incentives or information without considering all the factors that can influence their response. These factors include understanding the rules, social norms (what everyone else is doing), cultural practice, and the way information is presented. Sometimes, a small change can have a big effect. For example, simplifying documents, using checklists, or sending text message reminders can all have a positive effect on how people behave.

Does behavioural science work?

International use of behavioural science is now widespread, with evidence that applying its principles can improve outcomes in many areas of public policy, including justice, health and the environment. Aotearoa New Zealand, as with every country, is unique and people will respond differently to changes. Our team uses evaluation methods to find out how well our solution designs work, and who they work best for.

What we do

The BSA capability has four broad functions:

Understanding behaviour: Carrying out qualitative research and fieldwork and reviewing behavioural science literature.
Nudging: Applying relatively small tweaks to existing operational processes, such as letters, forms and text messages, to make them more effective in achieving their goals.
Advice: Providing advice on policy and service design, and their likely effect on behaviour.
Capability building: Providing training, tools and information to support others in applying behavioural insight principles to improve outcomes.

Our work

Below is an overview of some of the projects BSA has worked on.

Self-help guides

Effective virtual meetings

“You’re on mute”, “I can’t see you”, …*stone silence*… Meetings have looked remarkably different since we started having so many of them virtually. Now virtual meetings are a staple of our working lives.

Yet, virtual meetings can be unproductive and well, awkward. In this guide we use behavioural science, the study of how people behave, to provide some principles about how to have virtual meetings. How do we connect with each other while online? What does the science of creativity say about how to brainstorm effectively? How do we avoid zoom fatigue? The answers to these questions are in this very guide.

Guide to effective virtual meetings [PDF, 308 KB]

Simplifying messages

Our justice system sends messages all the time, through letters, texts or posters. Whether the aim of the message is to help the reader understand information or encourage a specific action, having a message that is clear, easy to understand and quick to find will strengthen the effectiveness of the message. BSA’s guides outlines how to improve messages with five practical steps:

Identify what you want your message to achieve (for example, inform, influence, call to act)
Make your key points stand out
Make your message easy for people to read
Know who is sending your message and when
Measure the effect of your message on behaviour outcomes

Guide to simplifying a message [PDF, 328 KB]

Guide to sending effective emails [PDF, 609 KB]

Whāriki Haumaru: Partnering with Māori Wardens to Reduce Warrants to Arrest

When someone misses a court date, a warrant can be issued and their case delayed, adding stress for defendants, whānau and victims. Whāriki Haumaru works with Māori Wardens and New Zealand Police to phone people with active Warrants to Arrest (WTA) and guide them through making a voluntary appearance at court. Callers use a script embedded with Te Ao Māori values (whanaungatanga, pono and manaakitanga) and behavioural‑science principles (procedural justice and implementation intentions).

A six‑month proof‑of‑concept in the Eastern District showed that defendants who spoke to Māori Wardens were 29 percentage points more likely to clear their warrant than those who could not be reached.

We then tested the approach at scale in Auckland—the region with the highest number of WTAs—using a randomised controlled trial. More than 1,600 defendants were allocated to no call, a call from a Police officer, or a call from a Māori Warden. Compared with the no-call group, placing a call reduced WTAs by 4.9 percentage points, and by 31 percentage points when the call connected. Outcomes were the same whether the caller was Police or a Māori Warden, showing that a timely, helpful reminder is what matters most.

During the trial, 44 WTAs were withdrawn, which represents a return on investment of 3.4 for every dollar spent. Given the success of the initiative, we’re working across the sector to identify further opportunities to free up resources and improve outcomes.

Protection Order information

Protection Orders are formal legal documents and can be difficult to understand. BSA worked with stakeholders across the justice sector to develop a coversheet for Protection Orders, simplifying information for both respondents and applicants. The aim of the coversheet is to help respondents understand what’s expected of them and reduce accidental breaches, as well as inform applicants of their rights. The coversheet was a finalist in the 2021 Plain English awards.(external link)

Protection Order cover sheet for respondents [PDF, 548 KB]

Protection Order cover sheet for applicants [PDF, 560 KB]

Encouraging people to pay fines

At the end of 2020, there was $567 million worth of fines owed to the Ministry of Justice. Many people do not pay their fines on time because they simply forget. However, their behaviour can be influenced by prompts that make it easier for them to pay, or that trigger them to consider what future costs they can save by taking action to resolve their fines now.

We have written a number of reports about trials that have used nudging to encourage people to pay their fines. Some of the trials had significant results, including:

Changes to fines reminder letters, using a social norms message “The vast majority of people pay their fines. You are in the small minority that still has to pay” resulted in a marked increase in fine payments. The letters were estimated to result in an additional $300,000 repayment within 28 days of sending reminder letters, plus up to $1.7 million if people who make arrangements go on to pay in full each year.
Changes to the deputy registrar summons letter, including a diagram that explains where the person is in the fines process, was estimated to lead to $600,000 to $960,000 more in payments during the 28-day payment window. This excludes payments that are made through arrangements, so the real financial impact could be much bigger. In one year, it would also mean 6,700 to 10,200 more people would take an action to resolve their fine that prevents MoJ from taking further enforcement actions.
Sending a text message to people seven days before a fine becomes overdue was estimated to benefit 6,300 people each year, by helping them avoid additional fees worth $640,000.

The letters and text messages found to successfully improve fines collection have now been rolled out as BAU.

Get in touch

Reach the team at behaviouralscience@justice.govt.nz

This page was last updated: 01st May 2025