In the last decade's intensive study of all sorts of social and economic time series, it has become clear, it seems to me, that the usual time series… - Ragnar Frisch

[The] length of the cycles and the tendency towards dampening are determined by the intrinsic structure of the swinging system, while the intensity (the amplitude) of the fluctuations is determined primarily by the exterior impulse. An important consequence of this is that a more or less regular fluctuation may be be produced by a cause which operates irregularly.

We may perhaps start by throwing all kinds of production into one variable, all consumption into another, and so on, imagining that the notions 'production', 'consumption', and so on, can be measured by some sort of total indices. At present certain examples of micro-dynamic analyses have been worked out, but as far as I know no determinate macro-dynamic analysis is yet to be found in the literature.

In this essay on econometrics in its conception and its use in economic planning for the betterment of man’s fate, I will try to cover a very broad field. When talking about the methodology in the particular fields mentioned - about which I am supposed to have a little more than second hand knowledge - I have always found it utterly inadequate to focus attention only on these special fields without seeing them in a much broader perspective. Therefore it was inevitable that I should have to include in the field of vision of this paper also some branches of science where I can only speak as a layman, hopefully as a somewhat informed layman. For whatever blunders I may have made in these fields I must ask for the reader’s forgiveness