ABSTRACT
For Irving Fisher, index numbers where formulae of a certain type, and in The Making of Index Numbers (1922) he dealt with the many that had been proposed. Were these answers to a question, their correctness would depend on the question. But they were answers that had been provided without a definite question, so making the choice between them was difficult. However, a consistency in understandings about price indices requires a formula to have certain properties, and from these Irving Fisher produced his tests.
