It upsets me when I read things like this (click here if you can't see the embedded tweet above). I think it creates a false sense of a free lunch and ignores all of the nuances and complexities associated with inclusionary zoning.

IZ is an obligation to provide a certain number of affordable units in new housing developments. There's a lot of detail and debate around where this should apply, how much needs to be provided, and at what degree of affordability.

But at the end of the day, it's important to keep in mind that at meaningful levels of affordability, these IZ homes are going to be built at steep losses. More info on the economic impacts of IZ can be found here.

The simple math is that the costs to build these homes are going to be greater than the revenues that they bring in. Which is why developers aren't out building affordable housing everywhere. There's no margin.

In order to build, somebody or something needs to provide a subsidy so that this revenue-expense shortfall can be made up. How this works its way through the market is where I have tried to focus the discussion when writing about IZ. There are complexities. Some lessons from Portland, here.

But to just assume that these costs will get magically absorbed by housing developers, with no other knock-on effects or distortions to the market, is incorrect.