Substitution Method

a method for eliminating systematic measurement errors caused by errors in the measuring instrument used to compare the quantity being measured with a standard. In the substitution method the value of the quantity being measured is not found indirectly, from a reading of the measuring instrument, but rather from the magnitude of the standard, which is selected or regulated in such a way that the reading of the measuring instrument remains the same when the quantity being measured is replaced by the standard. For example, when weighing an object on a beam balance, the object is taken from the pan and replaced by weights of equal total weight; the balance will show the previous reading (the Borda method). The substitution method is extensively used in measuring electrical quantities, such as resistance, capacitance, and inductance.