The unemployment rate as a measure of a physical property of a spatially dispersed population

We are set upon the task of devising a way of visualizing a smallscale physical model of a nation's population of people, showing its spatial arrangement at each of a succession of moments in time, and thus something about how a thing of this kind develops and evolves over the course of time. In this model, as we have imagined it to be, each member of the population would be represented by a small, thin disk that is initially undifferentiated. We are now to consider what this developing configuration may be supposed to look like when the disks representing the members of the population are differentiated so as to show their respective momentary employment statuses. We shall think of this differentiation as being done by color: a transparent disk representing a person who is not at the moment a member of the labor force; a green disk if the represented person is an employed member at that time; and a red disk if the person is an unemployed member.

If one can bring himself to suppose that these three categories–nonmember, employed member, and unemployed member–can be well enough defined so that census enumerators would be adequately instructed upon how to classify the real people constituting the nation's population at any moment, he may at least imagine having at hand the requisite data for constructing a model sequence showing what this component of the economy πt will have looked like in fact, developing as it actually did develop during some selected period of time.