S.D. Codified Laws § 62-9-3
The percentage of hearing loss shall be calculated as the average, in decibels, of the thresholds of hearing for the frequencies of five hundred, one thousand, two thousand and three thousand cycles per second. Pure tone air conduction audiometric instruments properly calibrated according to accepted national standards such as American Standards Association, Inc. (ASA), International Standards Organization (ISO), or American National Standards Institute, Inc. (ANSI), shall be used for measuring hearing loss. If the losses of hearing average twenty-five decibels ANSI or less in the four frequencies, such losses of hearing do not constitute any compensable hearing disability. If the losses of hearing average ninety-two decibels ANSI or more in the four frequencies, then the same shall constitute and be total or one hundred percent compensable hearing loss. In measuring hearing impairment, the lowest measured losses in each of the four frequencies shall be added together and divided by four to determine the average decibel loss. For each decibel of loss exceeding twenty-five decibels, an allowance of one and one-half percent shall be made up to the maximum of one hundred percent which is reached at ninety-two decibels.
SDCL 62-9-3