The two studies described below were made as part of a large-scale programme of official research into a series of topics relating to fertility, mortality and migration. The outcome of all this research (including that recorded below) will be published by the Government in due course but the manner and place of publication have not yet been decided. Although the present paper is announced under joint authorship, it is not a fully integrated effort: Part 1 was devised and written by the first-named contributor and Part 2 by the second. Nevertheless, their preparation took place over the same period of time and during that period steady contact was maintained between the authors by correspondence and meetings, and thus the work proceeded in parallel.

The discussion on Assessmentism (J.I.A.104, 205) was opened by Mr. M. D. May.