'transition', has had a strong impact on demographic research (Thornton 2001). The centrality of fertility postponement with the SDT is evidenced by Van de Kaa (1997). Based on observations on the 1965-1995 period, Van de Kaa postulates that the SDT is constituted by a complex set of sequences of stages. He identifies 15 stages, some of which are explicitly connected to the postponement
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.