Would a free $20k for all New Zealanders really work?

One of the Opportunity Party's key policies this election is a citizen's income. That would mean every adult New Zealander aged 18 and over would get about $20,000 a year. It would replace many main benefits, but the party says there would also be additional disability, child, housing and single parent support, it's also tax free. So who actually ends up paying for it? Chief economist at the think tank, the New Zealand Initiative Dr Eric Crampton spoke to Lisa Owen.