SEMAINE D'ÉTUDE SUR LE ROLE DE L’ANALYSE ECONOMETRIQUE ETC.
673
given point of time take the form of one-to-one correspondence.
No gap really exists in this case: the two ways of looking at
the production activities meet half-way, through the above
mentioned inverse matrix, which represents the analytical tool
for re-classifying the same transactions according to two dif-
ferent criteria and points of view (3). Of course, the input-
output model gives us more information. If we were simply
interested in what happens at a specific point of time, the
input-output model would be the obvious one to use because
it provides a more complete picture.
But as time goes on, the input-output coefficients change
and the inter-industry system breaks down. The connections
described above begin to vanish. Then it is only the vertically
integrated model that allows us to follow the vicissitudes of
the system through time. It may perhaps be useful to point
out explicitly how this happens. The process of technical
change, as has been remarked earlier, manifests itself in a con-
tinuous way at the level of the single units of production, espe-
sially in the form of slow improvements, coming from patiently
‘rying different raw materials, re-thinking the disposition of the
line of production, eliminating bottle-necks in the production
process, trying new similar products, etc.. Even when new
methods of production or new products are invented, their
introduction into the economic system very rarely takes the
form of a sudden change. Most of the time, the new products
or the new methods are operated uneconomically for a period,
antil experience and slow improvements put them on a com-
petitive footing and prepare the ground for further improve-
(3) Professor LeoNTIEF himself has, on a couple of occasions, adopted the
vertically integrated type of classification. See especially Domestic Pro-
luction and Foreign Trade: the American Capital Position Re-Examined,
« Proceeding of the American Philosophical Society », vol. 97, No. 4,
Sept. 1953, and Factor Proportions and the Structure of American Trade:
Further Theoretical and Empirical Analysis, « Review of Economics and
Statistics ». Nov. 1956.
10] Pasinetti - pag. 103
