‎"KOOPMANS, TJALLING.‎
‎Identification Problems in Economic Model Construction.‎

‎Chicago, The University of Chicago, 1949. 8vo. In the original printed wrappers. Offprint from: ""Cowles Commission Papers"", New Series, No. 31. Occassional underligning in pencil, otherwise fine and clean. Pp. (1), 448-66.‎

Reference : 48850

‎Offprint of Koopmans's paper in which he emphazised the need for identification of parameters, in particular when there is a change in structural paramters between the period of observation and the period to which the prediction applies. ""For example, assume a model that shows consumer's demands for jeans depends on prices and on their income. If there is any change in consumers' preferences, futures expectations, or a change in the tax rate between the period of observation and the period to which the prediction applies, there will certainly be some effect on the parameter values of this model."" (Wahid, Frontiers of Economics: Nobel Laureates of the Twentieth Century, 1969-1999).Koopman was awarded the Nobel price In Economics for his ""contributions to the theory of optimum allocation of resources"".‎