Since the first caveman decided to trade up for a new hole in the ground, it’s been easy to figure out how much real estate is worth.

Just offer the property for sale and see what someone is willing to pay.

Alas, that method doesn’t always work anymore.

Even if a willing seller and a buyer agree on a deal, it’s up to the appraiser to give it a thumbs up.

More than a third of homebuilders say they’ve recently lost or had to scramble to complete sales because the appraiser said nope, according to a recent survey by the National Association of Home Builders. The problem is probably just as bad for residential agents.

“Even if the seller can get his price, he has to get an appraisal before the buyer can get a loan,” said Mary Frances Burleson, president of Dallas’ biggest residential sales firm, Ebby Halliday Realtors. “It doesn’t make any difference how much you want.”

As you might imagine, real estate folks are in a lather over this.

At the recent International Builders Show, I heard a lot of caterwauling about homes sales getting killed by picky appraisers.

“A few years ago, appraisers were accused of inflating the price of homes,” said Paul Emrath, a researcher for the National Association of Home Builders. “Now, they are very sensitive and don’t want to be accused of appraising things too high and are sort of going the opposite direction.”

If you believe that home prices are turning the corner, expect a lot more problems with appraisals.

Real estate appraisals are about yesterday’s news. They’re based on what something sold for last month or last year, not what the market is doing today. In periods when values are changing direction, it’s a given that appraisals will lag.

This doesn’t much matter when prices are going up. If someone is willing to pay a certain price, the value is probably there.

But now there’s pressure on appraisers from lenders and government regulators to scrutinize each real estate deal.

“It should be pointed out that neither the buyer, the seller, the real estate agent nor the builder is the client of an appraiser in a typical real estate transaction,” said Austin appraiser Jim Amorin, immediate past president of the nationwide Appraisal Institute. “In transactions where buyers are seeking loans, our clients are the lenders.

“Competent and qualified appraisers provide lenders with objective information and value opinions that help protect them from making questionable loans and investments and help them minimize risk,” he said.

And that can mean quashing a pending real estate sale.

“We have certainly been taking it on the chin lately from the builders,” Amorin said. “I empathize with them, but there is a fundamental issue in the market the appraisers didn’t create.

“Good appraisers reflect what is taking place, and sometimes that means a home appraises for less than the builders believe it may be worth.”

How that gets decided is the issue. And Amorin is the first to admit that “not all appraisers are created equal.” He said states need to do a better job of enforcing appraisal standards.

I worry that by the time that happens, the real estate recovery will have been held back.

Until properties start trading at higher prices again – regardless of what they sold for six months ago – we won’t see a rebound in the housing market.