Yes, they will spend more, obviously. But, typically, if you estimate the impact of a tax rate decline, it would never pay for itself under normal circumstances. The amount of the increase in revenues as a result of the stimulus impact of tax is never going to be sufficient to pay for itself. The overall tax in Canada is 15% of GDP. If you reduce taxes by one dollar, that tax decline has to essentially stimulate six dollars of GDP to pay for itself. That kind of a multiplier of one dollar of tax decline creating six dollars of GDP is an extremely large multiplier. I'm not aware of any standard macro model that people use for this kind of assessment that can provide that kind of a multiplier.
On November 3rd, 2014. See this statement in context.