The property of unit-treatment additivity is not invariant under a "change of scale", so statisticians often use transformations to achieve unit-treatment additivity.
ðə pɹˈɑːpɚɾi ʌv jˈuːnɪttɹˈiːtmənt ˌædɪtˈɪvᵻɾi ɪz nˌɑːt ɪnvˈɛɹiənt ˌʌndɚɹ ˈeɪ "tʃˈeɪndʒ ʌv skˈeɪl", sˌoʊ stˌæɾɪstˈɪʃənz ˈɔfən jˈuːs tɹænsfoːɹmˈeɪʃənz tʊ ɐtʃˈiːv jˈuːnɪttɹˈiːtmənt ˌædɪtˈɪvᵻɾi.