There are a couple of things. People talk about our knowing the marginal impact that the changes in income splitting are going to have to the labour supply of women as if we know it to the decimal point. One of the problems with that type of analysis, one reason I was never a fan of this when I was at Statistics Canada and am still not a fan, is that it assumes other things are equal. Well, other things aren't equal.
We know, for example, that the lowest women's labour force participation in the country is in Alberta. Why? It's because with husbands who earn more than $100,000, women tend to stay home more often.
That's changing rapidly in Alberta. If Alberta raises the minimum wage from $10 to $15, that's going to have big impacts on labour supply.
There are many other things moving.