Constitutes a guide for carrying out comparative tests of fabric washing products in such a way as to realistically reflect the performance of the products likely to be used by consumers. It gives details of the variables to be considered, indicated the significance and importance of each of these variables, and privides a basis fornthe drawing up of adequate comperative test methods which will give a valid estimation of the performance of a fabric washing out product when two or more products are compared during the same series of tests.