Sprenkle examined warrant and stock prices for the "classic boom and bust period" of 1923-1932 and for the relative stability of 1953-1959, hoping to estimate from those prices "the market's expectations and preferences," in other words the levels of expected stock prices and their anticipated standard deviations, and also investors' attitudes to risk as expressed by the price of leverage. His econometric work, however, hit considerable difficulties: "it was found impossible to obtain these estimates." Only by arbitrarily assuming no expected appreciation in prices and testing out a range of arbitrary values of the price of leverage could Sprenkle make partial progress. His theoretically derived formula for the value of a warrant depended on parameters whose empirical values were hard to estimate empirically (Sprenkle 1961, pp. 204, 212-213).

Donald MacKenzie, An Engine, Not a Camera, loc. 538