Are housing deals falling apart because of Henny-penny appraisals? That’s the contention of the National Association of Realtors. But it’s an argument that bears a little more consideration for what it says and what it means.

In its monthly report on the housing market, released last week, NAR Chief Economist Lawrence Yun tried to explain why the national housing sales numbers for May didn’t look as rosy as NAR expected them to. With actual year-over-year sales numbers in the tank, the housing trade group has been trying to find a silver lining in its monthly housing statistics. It thought it had done so with its Pending Sales Index. This is where NAR tracks the number of offers that have been accepted. Where actual home sales are a trailing number, the Pending Sales Index is supposed to be a leading indicator: With buy-sell offer in hand today, a real estate deed should follow shortly.

The Pending Sales Index was growing, and that’s a good sign. It certainly meant that more potential buyers were making offers on homes. But the number of homes that closed in May was substantially less than what the Pending Sales Index had predicted.

No sales organization is foolish enough to believe that every customer who says “I’m interested” is a deal that will actually close. NAR isn’t that naïve either. But housing sales are a little different than most deals. Getting the customer to say “yes” is just the start of the close. From there, a lot of other factors all have to line up just right to get to commission time.

To Yun, the answer is simple: “Pending home sales indicated much stronger activity, but some contracts are falling through from faulty valuations that keep buyers from getting a loan,” he said flatly.

Yun, and NAR as a whole, makes the claim that it is the appraisal industry using faulty valuations that is causing deals-in-the-works to become deals-down-the-drain. NAR may be right about the ultimate effect, but it is off the mark about the process.

That is, it’s likely true that closings are getting nixed because the appraisals aren’t coming in to support the sales price. But that doesn’t mean the appraisal is wrong.

Since May 1, appraisers working on loans that may be sold to Fannie Mae or Freddie Mac must include in their valuations a look at comparable sales of “distressed” properties – read that as foreclosure sales, REO turnarounds and short sales. Yun would have it so that such properties weren’t part of the valuation process.

“Lenders are using appraisers who … compare traditional homes with distressed and discounted sales,” he said. “In the past month, stories of appraisal problems have been snowballing from across the country with many contracts falling through at the last moment. There is danger of a delayed housing market recovery and a further rise in foreclosures if the appraisal problems are not quickly corrected.”

But even NAR admits that, nationally, upwards of a third of all property sales these days are “distressed” properties (In Massachusetts, the number is slightly under 10 percent). It would be unconscionable for appraisers not to factor those in to their valuation analyses. To a real estate agent, if someone is willing to offer $300,000 for a house, that’s what the house is worth. But to a lender, if four other comparable homes are selling for $200,000, then that’s what the house is worth – especially if that’s exactly what the lender would be able to get for the property.

Just listen to Bill Garber, a spokesman for the Appraisal Institute: “Appraisers reflect the market, and sometimes, the markets don’t act like we want them to or hope they will. Nonetheless, competent and professional appraisers understand this and develop credible estimates of value that ultimately ensure that lenders loan the proper amount, buyers don’t pay too much and sellers get a fair price.”

That’s probably small comfort to agents whose deals are crashing. But maybe the lesson to be learned here isn’t to throw away appraisal standards, but to come into potential deal better armed with market analyses that help agents figure out from the start whether those “pending sales” are anything to be counted on.