Two Kinds of Affordable Housing Policies for Two Kinds of Affordable Housing

Mathew Yglesias explains the affordable housing problem in urban areas in the United States by calling out two definitions of "affordable." Both are "things that a reasonable person could be interested in," writes Yglesias:

1. In one usage, the goal of improving affordability is to make it possible for more people to share in the economic dynamism of a growing, high-income city like Seattle.
2. In the other usage, the goal of improving affordability is to reduce (or slow the rise of) average rents in an economically dynamic, high-income city like Seattle.

Because these two definitions are so different, different policies are required to further the goals desired in each case. Yglesias points out the shortcomings of both approaches, and suggests that the best option might be to pursue both.