In contrast to the statements in ICRP publications since 1990, the effective dose E and its SI unit, the sievert, are not physics quantities or physics units. The definition for E weighs the physics quantity by weighting factors derived from radiobiology and radio-epidemiology. The effective dose is a protection quantity, a convolution of physics, radiobiology and radio-epidemiology. The radiation weighting factor Wr quantifies the effect of the microdeposition of radiation energy in tissue, on its carcinogenic potential, and is intimately related to the structure of DNA, and the fact that carcinogenesis is related to radiation insult to DNA. The tissue weighting factor Wt quantifies the empirically determined radiosensitivities of tissues, based on clinical observation and results from radiobiology and radio-epidemiology. The values of the radiation weighting factors Wr for radiation type r, rely on the fact that life is organised in cells, that cells contain DNA, that DNA insult by ionising radiation is carcinogenic, that the DNA molecule has two strands, and that the carcinogenic potential of ionising radiation is related to the relationship between the mean distance between ionisation events and the distance between the strands in the DNA molecule, because double-strand breaks in DNA are less repairable and more carcinogenic than single-strand breaks in DNA. It is hence abundantly evident that effective dose can in no way be classified as a physics quantity.