Appraisers also will use data from the Multiple Listing Service (MLS) to find properties that are similar to the property being valued. As with any other sample, size is everything; the more properties that are similar, the better the chances that the valuation will be accurate.
Fannie Mae and Freddie Mac appraisers are also required to obtain floor plans for desktop valuations to ensure that the property hasn't been significantly altered and that the available data are an accurate reflection of its value.
Again, while they're most common in real estate, the value of almost any tangible asset can be estimated with a desktop valuation. The key caveat, however, is understanding that desktop valuations, although convenient and often less time-consuming, are estimates, and a physical inspection of an asset will generally yield a more accurate valuation.