In a recent blog post, state economist Josh Lehner poked holes in many of the politically popular theories behind Oregon’s housing shortage, including labor shortages, low builder confidence and fewer lots.

The most likely explanation, he says, is the limited availability of credit after the recession. Other popular explanations don’t get to the heart of the problem or are mere symptoms of the shortage, such as a lack of available lots.

Housing issues have been the source of popular interest this legislative session and in Oregon generally: the Multnomah County Library’s “Everybody Reads” pick is “Evicted,” a study of renters and landlords in Milwaukee, Wis., by Harvard sociologist Matthew Desmond.

Last week, the Oregon House passed a bill that would lift a statewide ban on rent control.

Opponents of the measure, HB 2004, say rent control won’t solve the problem, which has more to do with a lack of housing supply for Oregon’s growing population, particularly in Portland.

One statistic getting bandied about both in the capitol and outside its marble confines: 66 people move to the City of Roses every day.

Lehner says the state’s land use policies probably isn’t behind the lack of homes.

This explanation is a particular favorite of Republican legislators, who wax philosophical on the regulatory burden presented by Oregon’s strict Urban Growth Boundaries and other land use policies.

Not so fast, Lehner says: Boise, Idaho, has a vacancy rate rivaling Portland’s, and Idaho has fewer restrictions on building. In fact, that’s the reasoning behind a Malheur County economic development proposal (the border county struggles to compete with Idaho due in part to fewer land use restrictions, proponents of the measure say).

“Given the underbuilding of housing is not an Oregon-specific issue, using Oregon-specific explanations does not get you very far,” Lehner writes.

What does make a difference? Limited access to credit for homebuilders, Lehner said.

“Finance and credit availability is a macro lever that can better explain national patterns than any localized issue can,” Lehner writes.

While there are tighter restrictions on lending — and banks may be more cautious — in the wake of the subprime mortgage fiasco, there are signs that the amount of loans has increased quickly over the past few years, Lehner writes. The number of outstanding loans is still less than half of what it was in 2008, though.