Peer-reviewed evidence about the New Zealand model of decriminalization shows that it's been incredibly positive for sex workers there.
We hear there's been an increase in trafficking in New Zealand since decriminalization was enacted. One of the problems with New Zealand's model of decriminalization is it didn't decriminalize migrant sex workers, so any migrant sex worker is captured in statistics as a trafficking victim. Of course, it looks like trafficking has increased, when that's not the case.