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PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 28 
FISHER 
I would generally concur with Professor HAAVELMO’s summary of 
the situation. If, in fact, there are a lot of exogenous variables 
which vary a great deal as compared with the disturbances, then 
reasonably good estimates can be obtained — although I would not 
agree that refined methods are not called for. In my paper I pointed 
out that such situations are likely to be very rare in the estimation 
of economy-wide econometric models. In such cases, I tried to 
show that one could improve the results substantially by paying 
attention to the causal structure of the model rather than by incau- 
tiously applying techniques designed for the ideal situation. 
FRISCH 
I am afraid that what I am going to say will be considered 
perhaps as black heresy, and if I am saying it, I hope you will 
understand that, when I voice this opinion, if I say it in a very 
outspoken way, it is not because of a feeling of unfriendliness to- 
wards members of our fraternity, it is merely to save time that I 
am putting it in an extreme way. 
Looking upon the problem of estimation in economy-wide mo- 
dels, I like to adopt the view-point of an economist who is called 
upon to give his advice to politicians. And if I look upon the matter 
in this way, I have an uncomfortable feeling that, in statistics, we 
are too frequently carried away by the terminology we use. You 
may say that terminology doesn’t mean very much, you can call 
a thing a straw hat, and use the concept in a precise way in your 
logical deductions. It is not so dangerons to call it a straw hat, 
because then everybody will understand that this is just a sort of 
numbering of your concepts. But if you use other words which in 
every day life have had a certain connotation, you may be 
obsessed by this connotation and, as I say, be carried awav through 
your terminology. 
16] Fisher - pag. 70