A Quantitative Approach to Medieval Population Change

Geographers and city planners, endeavoring to explain or foretell changes in urban population, sometimes use an approach called basic-nonbasic. A basic factor is one which brings in money from outside of the city and which usually sells its products beyond the city limits. The nonbasic factor furnishes services and supplies to the city. Thus a factory would normally be a basic factor, while grocery stores, barber shops, and similar institutions, together with most professional groups, would be nonbasic. A factory employing a thousand workmen would add to the city not merely the workmen's families but about an equal group of nonbasic families, perhaps a total of six or seven thousand persons. This concept is a very useful one in modern society and is worth testing for its possibilities for medieval settlements.