Secretary Julián Castro has called the U.S. Department of Housing and Urban Development "the department of opportunity," a phrase he repeated at a housing conference last week in Washington, D.C. The idea of housing as an opportunity to impact healthcare, education, and quality of life was the focus of the second How Housing Matters conference, held at the National Building Museum.

One of the co-sponsors of the event, the John D. and Catherine T. MacArthur Foundation, has funded a body of research on affordable housing and these related impacts. Their $25 million How Housing Matters to Families and Communities initiative, launched in 2007, funded 40 research projects on topics like housing vouchers and inclusionary zoning, and these findings are currently being released. For the MacArthur Foundation's interim director Julia Stasch, housing and development is an area of expertise. She has previously worked on affordable housing plans in Chicago as the commissioner of the city's housing department as well as former Mayor Richard M. Daley's chief of staff. She also worked as deputy administrator of the General Services Administration under President Bill Clinton. ARCHITECT sat down with Stasch during the conference to talk about the state of affordable housing and what she hopes will be the long-term impact of the initiative.

What do you think is one of the most important affordable housing issues today?
Preservation of existing properties that have been the subject of investment, either long in the past or more recently, because I don't think it's possible to build our way out of the deficit of affordable housing that we have in this country today.

And what is the role of design?
I think the role of design is paramount. I think that design has both an outward-facing aspect—how does a property face, integrate with, and inspire a community—and it also has an inward-facing aspect—how does it function for the people that live there.

The "poor door"—a separate entrance for low-income residents—in some New York mixed-income properties came into the news recently. Do you have any thoughts on that?
So, I'm very ambivalent about that. When I first heard about the poor door I was actually horrified. But I think that sometimes we have to set aside our natural reaction to things and focus on what is the ultimate goal that we are trying to achieve, and that is the maximum number of units for people with low and moderate incomes and sometimes if there are compromises that have to be made—and I'm not saying that the poor door is a good compromise—but I think that we have to weigh the ultimate goal against some of the interim steps that some people might feel are necessary. So, I don't endorse it, but I don't categorically reject it.

What are you most excited about in your current position right now?
One of the most exciting things in my current role with the MacArthur Foundation is actually seeing the fruits of a huge portfolio of research projects in housing. I think the 40 to 42 studies that we have supported is perhaps the single largest, most concentrated body of work about the relationship of various attributes of housing to outcomes in other domains—education and workforce and opportunity and health. The exciting thing is we have a body of research that could constitute the basis for, I think, a whole generation of new housing policies that will be smarter, that will permit folks that have resources to target those resources in a way for the maximum return on investment. So I'm very encouraged by the mechanisms that we are putting in place to make sure that that research matters for policy.

Your colleague, Ianna Kachoris, mentioned one of the initiative'sresearch projects, by Janet Currie and Reed Walker. This study found that rates of premature births and low birth weights went down in housing near highway tollbooths after express tollbooths were installed. How could this inform future development?
So I could see an architect or a developer saying, "Here, we have land, it's near transportation. Let's make sure that if we want the outcomes for the residents of our property to be the most positive... we are going to use our influence to make sure that the right transportation policy is in place, so that the appeal and the related positive outcomes of the development that we are going to undertake are maximized."

Have you seen that happen already?
No. But what it says is, "Developers and architects, take a look outside of the policy domain within which you typically function if you're going to try to maximize the appeal and the human outcomes in the property that you are going to design and develop."

This interview has been edited and condensed.