Mo. Rev. Stat. § 138.030: Oath of members — powers and duties.

1. The members of the county board of equalization shall each take an oath, to be administered by the clerk, to fairly and impartially equalize the valuation of all real estate and tangible personal property taxable by the county.

2. The board shall hear complaints and equalize the valuation and assessments upon all real and tangible personal property taxable by the county so that all the property shall be entered on the tax book at its true value. The board shall not reduce the valuation of the real or tangible personal property below the value thereof as fixed by the state tax commission.