ABSTRACT
This chapter deals with the steps necessary to measure the variable economic facts so as to bring them into relation with the modified variability-conscious theory. Each exchange transaction has thus two measurable "elementary" characteristics or dimensions which we call the "terms of exchange", showing wide yet accurately measurable variations. They are, the amount of service, goods, or use of goods that persons exchange, and the price per unit of such services or goods that persons pay, or obtain in exchange. An alternative measure of business fluctuation is that of business profit. The amount of profit is generally used rather than any rate of profit. The Statistical study of the secular trend was first attempted through measurement of prices, and the progress of the working class in "real" wages and the amount of meat, wheat, bread and so on consumed. Economic laws or "curves" of correlation-issue type may be either what Professor Edgeworth distinguishes as "concepts", or what he calls "propositions".
