A method was described to normalize wear-induced changes in the dynamic friction of surfaces lubricated with an additive in oil solution. Changing dynamic friction data were normalized by comparing them at equivalent degrees of boundary lubrication, determined by measuring the coefficient of friction of the surfaces in neat white oil. Friction tests were made with three different additives to demonstrate the method and its validity.Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE Lubrication Conference held in Atlantic City, New Jersey, October 8–10, 1968.