Imagine you're a researcher trying to understand what crimes lead to community sentences in New Zealand. You pull the official data. You find 5,610 sentences recorded under a single category: "Inadequate data available."

That's not a rounding error. That's one in every dozen community sentences handed down last year where the justice system either didn't record the offence type, or recorded it so poorly the data became unusable.

Five years ago, this problem barely existed. In 2019, just 90 community sentences fell into the "inadequate data" category. By 2022, it had jumped to 1,977. Now it's 5,610. (Source: Stats NZ, community-sentences)

This matters because community sentences are the justice system's main alternative to prison. When judges decide someone should serve their time in the community rather than behind bars, that decision is supposed to be tracked, analysed, and used to understand what works. But you can't analyse what you can't see.

The spike tells you something broke in the data pipeline between the courts and Stats NZ. Maybe it's a software change. Maybe it's understaffing. Maybe it's courts recording offences in ways that don't translate into the national system. Whatever the cause, the result is the same: a growing blind spot in our justice data.

Politicians love to debate what crimes should lead to harsher or lighter sentences. But this dataset shows we can't even reliably track what crimes are leading to the sentences we're already handing down. When the "inadequate data" category grows 18 times larger in five years, that's not just a technical glitch. It's a policy problem.

Community sentences include supervision, community work, intensive supervision, and home detention. They're meant to reduce reoffending while keeping people connected to family and work. Whether they're working is a question we should be able to answer with data. Instead, we have a question mark next to 5,610 sentences.

The trajectory is clear: 309 in 2018, 90 in 2019, 93 in 2020, then the jump to 1,977 in 2022 and 5,610 now. Something changed after 2020, and it's getting worse, not better.

You can't fix what you can't measure. And right now, we're not measuring a growing slice of our justice system at all.