(16 
PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 28 
1943). The literature of the area is large and rapidly expand- 
ing. The high goals of macroeconomic model building, that 
much is now clear, are an important incentive for the develop- 
ment of new techniques in quantitative economic analysis. 
Thus in the short period of 25 years it has become manifest 
that macroeconomic model building is a mighty challenge to 
econometric method. At the same time it has emerged as a 
significant factor in the long range scientific evolution. 
It is appropriate to evoke the long range perspective if we 
call to account in the challenge, asking for the results thus far 
obtained in macroeconomic model building. Immediate bene- 
fits of an indirect nature have often and rightly been emphas- 
ized, including the build-up of knowledge about macroeconomic 
facts, the improvement of statistical data-collection, and the 
training of new cadres of econometricians in theoretical and 
applied work, all of which are tangible boons that cannot be 
overrated. As to direct results in the form of forecasts and 
other types of operational inference from the models, the 
horizon is eagerly watched for signals of progress. On this 
score the outlook is more undecided, and leading authorities 
have voiced scepticism and disappointment about the reported 
achievements. A symptomatic feature is the recent symposium 
in Econometrica (!) with the motto « Simultaneous equation 
systems: Any verdict yet? » But here patience is in order, 
for, to repeat, 25 years is a short time to master the tremendous 
tasks at issue. 
The Study Week, a most felicitous initiative of the Pontifical 
Academy of Sciences, provides a forum for unprejudiced ap- 
praisal of ends and means, aspirations and actual achievements 
in macroeconomic model building. The timing of the Study 
Week could not have been better. There is plenty of progress 
in the many avenues of scientific research and development 
that run together in a fullfledged macroeconomic model. On 
(1) Econometrica, October 1960, Refs. 6 and 7. Cf. also Refs. 8 and o. 
21 
Wold - pag. 2