-89-


 The difficulties involved in developing demand projections are
considerable. According to Fulmer,

 There are three major problems, and numerous lesser problems,
 in preparing economic projections. First, it is essential that
 an orderly pattern in past behavior be isolated and meas-
 ured if possible. Second, it is necessary to construct reason-
 ably descriptive models third, application of the model or
 models is dependent upon development of parameters which consti-
 tute the model.57/

The need for projections of economic change over time is readily appar-
ent. However, as Kuznets has stated most concisely,

 Empirical observation can relate to the past alone any
 projection from the past into the future cannot possess
 empirical validity in the way that a proposition having an
 identifiable referrent in the past can. We cannot ask about
 a statement concerning the future, "Is it true?" The
 answer to this question no matter how strongly supported by
 elaborate empirical study of the past, is merely a judgment
 that cannot be fully tested, and is, in that sense, an act
 of faith.58/

Thus, while proper procedures for making long-run, or at times even
short-term, economic plans generally require some form of projections
of the relevant factors, they must always be used with full recognition
of their inherent limitations. Further, their application in specific
situations shouldn't be made without reference to more recent or valid
sources of information.


 Method Used in Projecting Fluid Milk Products
 Consumption in Florida in 1970

 In selecting a method of projecting consumption of fluid milk
products in Florida to 1970, past studies of the demand for fluid milk
were reviewed. It would appear that reliable quantitative measures of
various factors affecting the demand for milk products, other than


 57/ John L. Fulmer, "Problems in Measuring and Projecting
Economic Growth," paper presented in graduate seminar on economic
growth, Department of Agricultural Economics, University of Florida,
Gainesville, Florida, April 14, 1961.

 58/ Simon Kuznets, "Concepts and Assumptions in Long-Term Pro-
jections of National Product," Studies in Income and Wealth, Vol. 16
(Princeton University Press: National Bureau of Economic Research,
1954) p. 11.