In December 2017, a Thai man named Phudit Kittitradilok was convicted of swindling 2,400 people out of 574 million baht (£13 million) in a Ponzi scheme that promised high return investments.

He was sentenced to a staggering 13,275 years in jail – an amount of time longer than the entire Neolithic era. But in actuality, thanks to Thailand’s penal code that limits prison sentences, Kittitradilok will only end up serving 20 years.

Still, there’s something about the idea of a long prison term that gives the impression that justice is being served. And while Kittitradilok’s case was mostly optics, plenty of people around the world really do spend their whole lives behind bars.

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For example, Terry Nichols, one of the accomplices in the 1995 Oklahoma City bombing, was given 161 life sentences with no possibility for parole.

But does a long prison sentence actually keep the streets safer? We considered the evidence.

Prison’s purpose

When a judge hands a sentence to someone who’s about to go to jail, there are four main factors that go into the decision. There’s retribution (punishing the person for doing something wrong), rehabilitation (correcting problematic behaviour), safety (keeping threats out of the community) and deterrence (making sure both they, and others, are scared off of breaking the law in the future).