Appraisers just can't get it right.

During the housing boom, mortgage brokers, real-estate agents, and even borrowers sought out appraisals supporting the highest possible home price. Appraisers, fearful of losing business, inflated their valuation findings, which exacerbated the run-up in home prices.

Now, after nearly 4 years of home-price declines, appraisers are getting it wrong again -- but in the other direction.

On May 1 -- while the financial media focused on construing a blip up in housing data as signs of an imminent bottom -- little was made of new appraisal guidelines that went live and immediately began to eat away at the core of the nascent housing "recovery." To be sure, trade groups like the Mortgage Bankers Association and the National Association of Realtors (NAR) fought the revised rules, but to no avail.

Stemming from a lawsuit filed by New York Attorney General Andrew Cuomo alleging Washington Mutual (JPM) and First American Corp illegally conferred on the results of home appraisals with the goal of inflating prices, the new rules put up a Chinese wall between banks like Citigroup (C), Wells Fargo (WFC), Bank of America (BAC), and appraisers. The goal was to create an environment where appraisals would reflect an expert's unbiased assessment of a home's true value, rather than evaluations tailored to a lender's desire to make a loan.

The new rules affect loans guaranteed by Fannie Mae (FNM) and Freddie Mac (FRE), but since the 2 government-run mortgage giants effectively control the secondary mortgage market, they've become the defacto guidelines for the entire industry.

In order to separate lenders and appraisers, appraisal-management companies (AMCs), cropped up, offering banks access to a network of appraisers around the country. This makes the appraiser selection process random, preventing collusion. And while AMCs claim appraisers are selected using proprietary scoring algorithms that evaluate performance, the reality is that jobs are handed out on the basis of fastest turnaround time and lowest cost.

In short, we've traded bias for incompetence.