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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 incautiously
 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 towards
 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 models,
 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