Yes, for sure. I'm not a tax expert, honestly; I've just educated myself on this issue. I've looked at a lot of experts' writings on this, and all the evidence shows that the more we decentralize a tax system, the more regressive that tax system becomes—for example, Marc Lee in 2007 and Kesselman and Cheung in 2004.
As Lee and many experts have found, the progressivity in Canada's tax system largely stems from federal taxes. This is even more the case now as the federal government has introduced more progressive tax measures at both the top and bottom ends of the tax system.
It's driven not just by politics, but also by imperatives. We have much greater inter-regional than international mobility, so it's really important that the federal government is involved in the development of the policy, the administration and the collection of taxes. Otherwise, what we might see, and what we have seen historically, is an eroding tax fairness in Canada.
Models show that clearly there has been progressivity that stems from federal taxes. Those models are supported in a lot of studies, as I mentioned during my presentation. I'd be happy to provide the committee with links and copies of those various studies.