1188 PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 2§ 
have taken policy measures that would have prevented these expen- 
ditures. 
MALINVAUD 
Professor JoHNSON has shown us that long-term forecasts in 
agriculture were often very poor. I should submit that this is not 
surprising. The future is difficult to predict anyway; and quanti- 
tative economics is not an old science. Economist, who only re- 
cently started to work with real data, have still much to learn in 
order to predict better. 
Even considering the present achievements, I would not accept 
the conclusion that we should no longer try to make long-term 
projections, Whoever has to decide for the future, must have some 
idea of the future. Thus, the real alternative is between individual 
long-term projections and what I would call centralized long-term 
projections. Professor JoHNSON has not convinced me that we 
should only rely on individual projections, 
One of his claims is that individual errors are offsetting. But, 
in the first place, I doubt whether they really are. Great mistakes 
have been made during the past 15 years in various industries. My 
‘feeling is that, in most cases, the centralized projections were less 
wrong than the average individual projection. The centralized pro- 
jection had to fight against the common belief that was generally 
much too extreme. Such was the case for fuel during the European 
coal shortage, and again shortly after at the time of the Suez crisis. 
According to me, econometric studies are usually bringing into the 
discussion about the future some rational elements which are not 
taken into account by individuals who have no time to go into a 
serious analysis. 
In the second place, even if the errors were offsetting, we should 
not necessarily be satisfied with the situation. Offsetting errors do 
not imply good decisions. Each individual decides on the basis of 
his own mistakes. Decisions will then be inconsistent with one 
16] Johnson - pag. 48