I suppose the technical term is that one house is substitutable for another house. But I think that the fungibility of housing -- while by no means perfect or

I suppose the technical term is that one house is substitutable for another house. But I think that the fungibility of housing -- while by no means perfect or absolute -- gets at the core of the concept. It's like when you target funds in a large organization. Yes, your $100 donation goes to, say, fund program X, but money is fungible and the org can just pull $100 of its general funds out of program X and put it in program Y. Housing is of course less perfectly fungible than dollars, but at the end of the day almost all units of housing house one (1) household, and that household needed somewhere to go, and using this unit of housing for this household frees up more housing for another household.