(You can read part one and part two of this series here.)

One of the primary problems in the affordable housing debate is that the phrase "affordable housing" means different things to different people—and, more to the point, that different people don't know what they might be agreeing to by accepting the premise that housing is "unaffordable."

What is meant when someone says that we don't have affordable housing? What if my underlying definition of "unaffordable housing" is "housing that isn't free"? To have a useful conversation about affordable housing, we must establish some consensus around what our expectations are for both "affordability" and for "housing."

From my perspective, the first necessary point of consensus has to be that able-bodied Americans are expected to pay at least something for their housing. While that might seem like a superfluous thing to stipulate, it isn't. If housing is in fact a "human right" as some activists assert, then assigning any dollar figure or percentage of anyone's income is inherently a violation of that right. What sort of "human right" could be denied on the basis of cost?

If there is an expectation that people (in general) should be paying for their own housing, how much should people be expected to pay?

As the federal Department of Housing and Urban Development, or HUD, notes, there are many ways in which "affordability" can be defined by researchers and policymakers. Researchers and policymakers could look at average incomes in a metropolitan statistical area (MSA). They could use median incomes in a county and establish an absolute floor for affordable housing costs. They could create ratios, they could bundle together utilities with housing costs or not consider utilities at all, and they could transform data in myriad ways to come to reasonable, but radically different, conclusions.

You can see the issue.

But despite the plethora of possible (and possibly contradictory) affordable housing definitions, HUD has generally settled on a set definition of what is "affordable" that it applies to many of its programs. As the department explains on its website:

In the 1940s, the maximum affordable rent for federally subsidized housing was set at 20 percent of income, which rose to 25 percent of income in 1969 and 30 percent of income in 1981. Over time, the 30 percent [gross income] threshold also became the standard for owner-occupied housing, and it remains the indicator of affordability for housing in the United States. Keeping housing costs below 30 percent of income is intended to ensure that households have enough money to pay for other nondiscretionary costs; therefore, policymakers consider households who spend more than 30 percent of income on housing costs to be housing cost burdened.

Defining affordability can be like listening to good music—you recognize it when you hear it, and others may still disagree with you. But the HUD definition would seem to be a reasonable one, and that it has been adopted beyond the bureaucracy as a general rule makes it more compelling as a starting point for this discussion. While this "general rule" is a good starting point, the details for defining "affordable housing" matter, too. More on that in the next blog.