Most significantly, Florida relies on value in exchange, an appraisal principle. Value in exchange relies on market data.
Real property is defined by statute (see Chapter 192) as land, buildings, fixtures, and all other improvements to land ~ NOT including personal property. The personal property definition has four components. In Florida, tangible personal property is assessed and may be taxed too, also based upon value in exchange.
Real property comparables should be based upon unencumbered fee simple estates conveyed in arms length transactions. Definitions are found in 12D-51.003, Florida Administrative Code.
Ad valorem assessments should NOT include intangible values. Intangibles can include lease contracts and franchise agreements, which may be taxed but only by the State.
Assessments generally are based upon retroactive market data as of January 1st of each calendar year. Appeals are governed by the standards set in 194.301, Florida Statutes as well as 12D-9 and 12D-10, Florida Administrative Code.