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PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 28 
worthwhileness of the results. Such valuations are clearly quite 
essential to a sound appraisal of the worthwhileness of a proposed 
public investment project, and I think that all project appraisers 
should be grateful to the private sector for providing them with such 
values. I know of no other reliable way of obtaining them. I should 
consider the problem of appraising public investments much more 
difficult if there were not a private sector that established reliable 
market prices for the goods and services with which they are con- 
cerned. 
VAHALANOBIS 
Well, your recollection of the paper must be better than mine. 
If I may make a point here, if you are in a mixed economy, when 
you are planning investments you would have to take into account 
the behaviour of the private sector, which you cannot control di- 
rectly but only indirectly, before making your decisions about public 
investment. From that point of view, I think the programming of 
public investment becomes much more difficult than in a fully plan- 
ned economy in which everything would be decided more or less 
on mostly endogenous variables. 
DORFMAN 
Of course the presence of an unpredictable private sector pre- 
sents the project appraiser with certain difficulties. My impression 
is that the same difficulties arise in a fully collectivized economy. 
In a collectivized economy there would not be a private sector to 
confound and confuse a project designer or appraiser, but there 
would, of course, be other bureaus and other administrations within 
‘he public sector. The project appraiser and planner dealing with 
andertakings in one branch of a centralized economy, for example, 
‘he branch that has to do with irrigation projects, would have 
31 Dorfman - pag. 22