SEMAINE D'ÉTUDE SUR LE ROLE DE L’ ANALYSE ECONOMETRIOUE ETC. , EU respecification of interdependent systems (A) into predictor relations giving ‘n° * - Unlike (B), the respecification (D) in general involves a change of the numerical parameters 3, T of the system. It would seem that the respecification (B) is more fruitful than (D). Respecification (B) is however so recent that only some of its implications have been explored “ AI LAIS I wonder if the distinction between the three cases you hav. denoted as « vector regression, causal chain, interdependent system » corresponds to a real difference from the point of view of the facts. What we observe in nature is continuous. Thus if we consider discrete series instead of continuous series, we introduce something which is handy for the calculation, but something which does not correspond to reality and which may result in the artificial creation nf a certain number of difficultie- HAAVELMO I enjoyed listening to Prof. WoLD’s paper. I think it was extre- mely clear in its presentation. I only have one comment — about something that bothers me a little bit. When he says to use this nr that method of approach. does he mean to use this or that (?) Respecification (B) provides a new approach for the statistical esti- mation of parameters in interdeneudent svsteme: see reference (b) in footnote (1) or Wold - pag. 61