SEMAINE D'ÉTUDE SUR LE ROLE DE L ANALYSE ECONOMETRIQUE ETC. 
11 
In the United States and Western Europe the major policy 
objective concerns the level of farm incomes. The major ana- 
lytical questions are not the same as the ones discussed above. 
The questions relate to the social costs of alternative policies 
and the effects of alternative policies upon the level and distri- 
bution of farm income and the size of the farm population. 
There does not now exist, for example, a convincing analysis 
of the effects of reducing the wheat price paid to German far- 
mers by 150 Dm per metric ton upon the average level of 
return to labor and capital engaged in agriculture. Nor does 
there exist an adequate analysis of the effect of the U.S. farm 
programs upon the level and distribution of farm incomes or 
of the effects of substantially reducing that level of expenditure. 
Basically, our difficulty is that we have not as yet been 
able to satisfactorily estimate the aggregate supply function for 
agriculture. Given the many variables that affect the aggregate 
supply function, when input prices must be allowed to change 
as output prices change, when factor supply functions are shift- 
ing over time and adjustments to changing factor and output 
prices do not occur instantaneously, it is perhaps understand. 
able that we have thus far made so little progress 
johnson - pag.