relative difference relative mean difference Expert Working Group Agreement: 2022-06-29 vote 6-0 by Jesus Lopez-Alcalde, Philippe Rocca-Serra, Mario Tristan, Janice Tufte, Harold Lehmann, Eric Harvey Brian S. Alper, Muhammad Afzal, Kenneth Wilkins, Joanne Dehnbostel A statistic that is a difference between 1 and a ratio of the two mean values being compared. Relative Mean Difference = 1 - ( a / b ) where a and b are mean values. The relative mean difference can also be defined as a statistic that is a ratio of the difference in means to the reference mean value. Relative Mean Difference = ( b - a ) / ( b ) where b is the reference mean value and a is another mean value. COKA group