A property appraisal is a very important piece of the approval puzzle lenders put together when evaluating a loan application. In reality, both an individual and the property must be approved separately. Regardless of the income, assets or creditworthiness of the borrower, if the property doesn’t disputing the appraisalmeasure up, there’s no deal. And when an appraisal comes in too low, the buyers then have some decisions to make.

Put more down payment to make up for the difference, renegotiate the price or cancel the transaction. But there’s one more thing buyers and sellers can do—dispute the appraisal.

Real estate appraisers will tell you right off the bat that appraising property is as much of an art as it is a science. One appraiser may give more value to a scenic view than another. Lush landscaping might up the value a bit while another licensed appraiser simply sees more lawn to mow. But before any of the nuances come into play, appraisers begin with hard data—closed sales.

Appraisers have access to the local multiple listing service, the database that contains all the buy, sell and rental information for residential real estate in the area. Before an appraiser does too much work, the first job is accessing the multiple listing service and compare recent sales with the subject property. If homes are selling for $200 per square foot and the subject is in the ballpark, then so far everything appears to work out as the value of the subject appears to match nearby properties.

But the multiple listing service only has the information that other real estate agents enter. Real estate doesn’t have to be entered in the multiple listing service to be listed for sale. Many times real estate is sold without a public listing. A so-called “pocket listing” that an agent owns but yet to make it public. If the property sells before the agent places it in the listing service, the appraiser won’t be aware of the sale.

If your property’s value is falling short, contact your agent to see if there have been any sales that would not have appeared in the listing service. This might take a bit of legwork, but agents get paid on commission and if there is no sale, there is no commission. Appraisers can only use the data in front of them—if there is more information out there, find and document it.