4.4.2. Sales Comparison Approach.Under federal law, unforced, arm’s-length transactions of properties in the vicinity of and comparable to the property being appraised, reasonably near the time of acquisition, are normally the best evidence of market value.438 The process of forming an opinion of a property’s market value through comparison with such comparable sales is known as the sales comparison approach to value.439 The sales comparison approach is normally preferred in federal acquisitions as the best evidence of value, but not to the exclusion of other relevant evidence of value based on market data.440 The essence of the sales comparison approach to value is the comparison of sales transactions to the property being appraised.441 “Generally, the more comparable a sale is, the more probative it will be of the fair market value” of the property being appraised.442 The converse is also true, as one court observed: 

Significant differences as to location, size, topography, market area, and recreational potential existed between most comparable sales and the subject property. This makes comparison extremely shaky because of the necessity of substantial adjustments required between the comparable and the subject.443 

As a result, the most recent sale of the property being appraised may well be the most comparable of all the comparable sales, as discussed further in Section 4.4.2.4.1.444