Appraisers try to compare properties using uniform measurements, and area is an important physical characteristic of a property compared when land or buildings are analyzed. Land area comparisons appear to be simplistic, until you consider why parcels sizes vary.

Most parcels of real property were subdivided, based on the U.S. Department of the Interior / BLM rectangular survey system, from square mile 640 acre Sections to 320 acre half-Sections to 160 acre quarter Sections to 80 acre, 40 acre, 20 acre, 10 acre, 5 acre, 2.5 acre down to 1.25 acre parcels. These parcels sizes, deemed "gross acreage" by the following Clark County definition, are often affected by survey adjustments, roadway dedications, utility easements and other factors and they can be reduced in size prior to becoming ripe for development.

Per Clark County, "Gross Acre" means an area of forty-three thousand, five hundred and sixty (43,560) square feet and includes the total area within the property lines of a lot or parcel of land before public streets, flood control channels or basins, or other areas to be dedicated or reserved for a public use are deducted from such lot or parcel, including property previously dedicated. (Clark County, Title 30, Unified Development Code, 30.08.030 Definitions)

Properties affected by public streets, alleys, and flood control channels or basins or other dedicated areas no longer fit the "gross acreage" size definition, since they have been modified. A 5.0 gross Acre site can be reduced to a 4.2 modified gross Acre site by roadway easement takings.

Since owners want to represent the largest site size possible, they don't dedicate roadway easements until they absolutely have to. It's easier to sell a 5.0 gross Acre site than it is to sell a 4.2 modified gross Acre site, even though they will have the same net usable area after roadway easements are taken from both. In fact, many sales are based on the total square footage, and individuals who haven’t made dedications have more than those who have made dedications.

The public has little knowledge of the difference between a gross Acreage size and a size reduced by dedications. Ads, MLS data and other property information sources do not differentiate between a true gross acreage size and a size after some dedications are made.

In my opinion there are three comparable land states. The gross acreage state, where comparisons can be made based when the subject and comparable sales meet the County definition; the modified gross acreage state, where some dedications have been made for roadways or for other purposes, however the property has not been “finished” and it is not ripe for development; and the “net acreage” state where all property dedications have been made and a site is ready to develop.