Demographic disequilibrium in early twentieth century Thailand falling mortality, rising fertility, or both?

Estimates of Thai crude birth and death rates date from 1920, when the former was around 20 per thousand higher than the latter, implying natural increase of two per cent per annum. Such disequilibrium cannot have been the norm over the long-term historical past, when population growth must have been comparatively slow. This paper explores the bases for likely past relative equilibrium between Siamese birth and death rates, then seeks to explain the disequilibrium apparent by 1920. Classic demographic transition theory postulates initially high birth and death rates, this equilibrium eventually being broken by falling mortality. In Thailand, however, there is likely to have been both significant mortality decline and appreciable fertility increase after 1850, as the virtual elimination of indigenous warfare, rapid growth of the export rice economy and the demise of slavery and corvee labour created a new domestic environment. Characterized by more dispersed, often frontier, settlement, this environment was unprecedentedly sedate and settled, afforded ordinary households a previously unknown level of control over their resources of labour, and generated optimism about prospects for the next generation.