• What is an appraisal? A process conducted to determine the value of a property, usually for financing purposes. It's different from the estimated market value, which is assigned by your municipality for tax purposes, usually by the county assessor.

• What's changed? Federal regulations have now separated the home buying/lending process from the appraisal process to ensure that an appraisal is being conducted objectively. Among the new rules are restrictions on contact between the lender and the appraiser and more strict requirements for comparable sales. Usually they require four to six comparables within a certain geographic range. Foreclosure sales have made the process even more difficult because appraisers must take into account that the comparable was a distressed sale.

• What's a comp? The terms "comps," "comparables" and "comparable sales" refer to prices paid for recently sold homes that are comparable in size, style and location. "Recent" can look back as far as six months, depending on the activity in the local market.

How can you protect yourself from short appraisals? Here are some suggestions for buyers and sellers.

If you're a buyer

• Tell your lender to find an appraiser who comes from your county, or perhaps a neighboring county.

• Request that the appraiser have a residential-appraiser certification and a professional designation. Examples include the Appraisal Institute's senior residential appraiser, or SRA, or member of the Appraisal Institute, or MAI, designations.

• Meet the appraiser when he or she inspects the home and share your knowledge of recent short sales and foreclosures that might skew the comps.

"Many appraisers are just pulling up data out of MLS (Multiple Listing Service) or off the deed at the courthouse and not checking it out," says Leslie Sellers, president of the Appraisal Institute in Chicago. "Most good appraisers will appreciate the information."

And yes, you can speak with your appraiser; the prohibition only applies to your lender.

If you're a seller

• Get an appraisal before you list a home. Search for a qualified appraiser in your area on the Appraisal Institute website.

• Use the appraisal to set a realistic listing price for your home.

• Give a copy of your prelisting appraisal to the buyer's appraiser. "They won't be offended," Sellers says. "The more professional appraisers will understand that you're just trying to add more data and another perspective."

• Question a low appraisal. There's always a chance the appraiser or a supervisor will take into account new or overlooked information.

— Jay Macdonald, bankrate.com