Dr Andrew Lensen from the School of Engineering and Computer Science and Dr Marcin Betkier from the Law School are eager to ensure AI has a significant role in the justice system. The researchers based in New Zealand built an Artificial Intelligence (AI) algorithm that predicts the length of court sentences.

But the question that may arise is whether the AI algorithm is fair enough to hand down the sentences. In the current justice system, society trusts judges to hand down fair sentences to the accused based on their knowledge and experience.

But how about AI? Can it judge better because it can eliminate the potential for bias and discrimination? And can AI substitute the judge’s knowledge and experience with its ability to analyse and predict large amounts of data?

Dr Andrew is optimistic that AI can help better sentencing performance in the court. The confidence comes from the use of AI to predict some criminal behaviour, such as financial fraud. Even though he has not tested the algorithm model in the courtroom to deliver sentences, he is confident in his idea that AI can have a role in the sentencing process.

Dr Andrew says when judges handle a case in the court, they have some “inconsistency” when passing a sentence for a convicted criminal. The inconsistency comes from a judge’s consideration of individual circumstances, societal norms and the sense of justice.

The moral decision and the sense of humanity are based on their experience and even sometimes change the law. Each judge uses their prudence in deciding the outcome of a case. Another “undesirable inconsistency” occurs as bias or even extraneous factors like hunger. Research in Israeli courts has shown that the percentage of favourable decisions drops to nearly zero before lunch.

Judges must ensure similar offences should receive similar penalties in different courts with different judges. Usually, to enhance sentence consistency, the justice system has prepared guidelines as a reference. This inconsistency area is the pain point where AI can help.

How AI Helps Judges

Most modern AI is machine learning, a machine learning algorithm that could learn the patterns in a database to predict patterns and outcomes. Therefore, AI can provide better sentence suggestions after the computer algorithm learns the patterns within a set of data.

Dr Andrew’s machine learning algorithm trained with 302 New Zealand assault cases. The sentences in those cases are between 0 and 14.5 years of imprisonment. The model quantifies sentences based on certain phrases and terms when calculating the sentence. Then the algorithm built a model that can predict the length of a sentence for a new case and explain why it made certain predictions.

The relatively simple model worked quite well within the average error of the model in under 12 months. The model associates the words or phrases such as “sexual”, “young person”, “taxi” and “firearm” with longer sentences. While shorter sentences were given to cases with words like “professional”, “career”, “fire” and “Facebook”.

Beyond Decision Making

In the future, AI could be used as an evaluation tool for judges. They could understand better their sentencing decisions and perhaps remove extraneous factors. The models also have the potential to be used by lawyers, providers of legal technology and researchers, to analyse the sentencing and justice system. Moreover, AI also can be used for controversial sentences and help create some transparency around controversial decisions.

Of course, the use of AI in the justice system may still be controversial. Most people are still keen that the final assessments and decisions on justice and punishment should be made by human experts. But maybe it is the right time need to give an opportunity to an “algorithm” or “AI” in the judicial system for the common good.

New Zealand is not the only country that explores the use of Artificial Intelligence (AI) in courtrooms. Several other countries like China and Malaysia have done similar things. In China, robot judges can decide on a small case. While in Malaysia, some courts have used AI to recommend sentences for offences such as drug possession.