The Wall Street Journal on May 6 ran an opinion piece with the headline “The Housing Crisis Is Over.” In it, Cyril Moulle-Berteaux, managing partner of New York-based hedge fund Traxis Partners LP, makes the case that the combination of falling housing prices and lower mortgage rates have made homes affordable again. Housing prices rose so far, so fast, during the boom, he says, that houses became unaffordable for many people. It now takes 19 percent of monthly income for the average home buyer to meet the typical mortgage payment, he says, and 31 percent of monthly income for first-time buyers. Those affordability levels haven’t been seen since the 1990s, he contends, and its affordability that stimulates demand.

Years ago when I was writing about the local business scene in the Chicago area, I had an auto dealer tell me his customers didn’t think about the price of a car they wanted, they thought about how much a month it would cost them to buy that car. So, he worried more about auto loan interest rates than he did about Detroit pricing decisions.

I think in many cases the same logic holds true for someone buying a house. Price is an abstract number, unless someone is paying cash, of course. What matters is the monthly carrying cost, which is a function of price, mortgage interest rates, and local property tax rates. Moulle-Berteaux argues that in the boom years, carrying costs got beyond most people’s ability to pay, and that drove buyers — especially first-time buyers — away.

An interesting piece, one you might want to print out and put up on your wall or include in your listing presentations to answer client doubts about when the market will improve.