Beyond Lowest‐Low Fertility: Why Post‐Transitional Populations Follow Divergent Paths

Abstract This paper argues for a paradigm shift in demography, moving beyond the alarmist and deterministic narratives fixated on “lowest‐low fertility (LLF)” (total fertility rate ≤ 1.3). Initially a useful heuristic, the LLF concept now obscures more than it reveals, as it conflates vastly different demographic trajectories across an increasingly heterogeneous global landscape. We demonstrate that factors like international migration, mortality reduction, and human capital are powerful mediators of population futures, often more impactful than fertility rates alone. Using comparative cases, we show that similar LLF classifications can lead to starkly divergent outcomes. Consequently, we propose retiring the LLF framework in favor of a multidimensional demography that situates fertility within an integrated system of demographic and socioeconomic factors, enabling more nuanced and effective policy responses to contemporary population change.