Missouri constitution
Article X: taxation
Section 14

The general assembly shall establish a commission, to be appointed by the governor by and with
the advice and consent of the senate, to equalize assessments as between counties and, under such rules as may be prescribed by law, to hear appeals from local boards in individual cases and, upon such appeal, to correct any assessment which is shown to be unlawful, unfair, arbitrary or capricious. Such commission shall perform all other duties prescribed by law.