SDCL § 10-11-58: Computation of median level of assessment in each county.

In order to determine the average level of assessment in each county the secretary of revenue shall compute the median ratio. The median ratio is the middle value in the array of ratios of assessed valuations to sales, from the highest to the lowest for the current year and one year preceding the assessment year. If there are fewer than ten sales, medians may, in the case of agricultural land, be determined by bridging sales information from adjoining counties or in the case of nonagricultural land from other municipalities.