BACKGROUNDAlthough demographers have long been interested in studying the historical fertility transition, there is still a lack of knowledge about disaggregated patterns. Identifying these patterns could help us to better understand the mechanisms behind the transition.OBJECTIVEThe aim of this paper is to explore social class differentials in fertility before, during, and after the fertility decline, in order to test hypotheses regarding a reversal of class differences during the transition.METHODWe use micro-level census data for Sweden 1880, 1890, 1900, 1960, and 1970 with individual-level information on occupation, which is used to measure class. Poisson regressions with parish-level fixed effects enable us to carefully control spatial heterogeneity in measuring class differences in net fertility (child-woman ratios).RESULTSThe relative differences were about as large in the early phases of the transition as they were in the 1960s. The fertility levels of the high-fertility classes were about 40% higher than those of the low-fertility classes. In the early phases of the decline, the upper and middle classes had much lower net fertility than lower skilled workers, who had the highest fertility levels. However, there was no clear gradient from the highest to the lowest socioeconomic status. Instead, it appears that the upper and middle classes had low fertility levels, while the fertility levels of the remaining groups were unchanged, and therefore remained relatively high. In the 1960s, members of the middle class had the lowest fertility levels, while farmers and rural laborers had the highest fertility levels.CONCLUSIONSThe results only partly confirm the assumption that there was a reversal in class differences in the demographic transition. Class was found to be important, but the pattern was not characterized by a simple gradient. Moreover, spatial heterogeneity was shown to explain about half of the observed differences between classes. The observed pattern suggests that the fertility transition can be attributed to both innovation-diffusion and the adjustment to new socioeconomic conditions.(ProQuest: ... denotes formulae omitted.)1. IntroductionThe decline of fertility in the demographic transition has been a major theme in historical demography for some time. Much of the literature focusing on the demographic aspects of the decline has sought to chart the process without actually explaining it. Other studies have offered explanations for the decline mainly at the macro level, identifying either innovation or adjustment processes as the main causal agents. Scholars have shown less interest in examining disaggregated patterns using micro-level analyses.One of the main issues that arises in discussions of the fertility decline is the extent to which fertility levels differ according to socioeconomic status, and how these differences evolved over the fertility transition. Most demographers appear to agree that having higher social status was associated with having higher fertility prior to the transition, but that this situation reversed during the transition, or even before it occurred (Livi-Bacci 1986; Skirbekk 2008). While it is therefore often assumed that higher social groups were forerunners in the decline (Haines 1992; Livi-Bacci 1986), the question of whether the change happened because new incentives were affecting the elite groups first (adjustment), or if it came about as a result of a diffusion of new ideas first adopted in these high-status groups (innovation), remains unresolved (see Haines 1992).As some of the differences in fertility levels between socioeconomic groups may have also been related to spatial differences in socioeconomic structure, rather than to social status as such (Garrett et al. 2001); it is essential that researchers control for the spatial aspect when analyzing socioeconomic stratification and fertility in national populations (see also Szreter 1996). …