Sir Michael Cullen wants to use the tax system to help us all behave better.

We have a few ideas to help build upon this noble pursuit.

Cullen’s Tax Working Group should begin by looking at the Four Capitals that Treasury knows will help enhance our wellbeing: natural capital, social capital, human capital and financial/physical capital. The tax system could be entirely redesigned to enhance those capitals.

Social capital may be the hardest nut to crack. Treasury points to the value of social connections, a “sense of unity”, pro-social norms and values, pro-social behaviour, and trust in institutions.

But how can we use the tax system to help with that?

Fortunately, China is leading the way. And we must follow - if we want to use the tax system to keep us better behaved, and to put in place Treasury’s wellbeing approach.

China is piloting a social credit system. Their approach has nothing to do with the bizarre economic theories once called Social Credit. Instead, it aligns perfectly with Treasury’s totally not-discredited wellbeing approach.

It is very simple. Everyone gets a social credit score. If you do good things, pro-social things – things that reinforce trust in President Xi’s institutions and encourage a sense of unity – your score goes up. Volunteering for a charity and separating your recycling can enhance your score. So can donating blood. These are all good things that must be rewarded.

If you instead decide to exhibit bad behaviours, your score goes down. Your score can go down for social microaggressions. Things like not turning up to a dinner reservation or leaving false product reviews. Ubiquitous facial recognition camera systems can assign demerit points for jaywalking. Soon they will be able to also assign demerit points for doing unmutual things – things that reduce the sense of unity and trust in institutions – like engaging in civil protest.

The Chinese pilot scheme so far rewards high-scoring citizens with things like shorter wait times in hospital and punishes low-scores with reduced access to public services and travel restrictions.

New Zealand can improve on that. Why tax things like income or consumption when we could instead harness the tax system to nudge us all towards better behaviour?

Touch your toes Comrade Smith. It’s worth 10 social credit points, and a small tax cut. Because we know it will be good for you, will strengthen the nation’s Four Capitals, and enhance wellbeing.

Trust us.