West virginia constitution
Article X: taxation & finance
Subsection b

The Legislature shall further prescribe by general law the manner in which each statewide reappraisal shall be employed to establish the value of the various separately assessed parcels or interests in parcels of real property and various items of personal property subject to ad valorem property taxation, the methods by which increases and reductions in value subsequent to the base year of each statewide reappraisal shall be ascertained, and require the enforcement thereof.