We build a dynamic quantitative spatial model with mobile households and endogenous fertility to analyze the efficiency of equilibrium fertility choices and city size distribution. City size affects the economy through three channels: a larger city population increases productivity, affects amenity levels (positively or negatively), and increases the cost of child care. We find that the competitive equilibrium is inefficient due to the intergenerational externality and excessively large cities have excessively low fertility rates. We calibrate our model to German county data and find that the resulting welfare losses amount to 14% of income.

We investigate how fertility relates to work from home (WFH) in the post-pandemic era, drawing on original data from our Global Survey of Working Arrangements and U.S. Survey of Working Arrangements and Attitudes. Realized fertility from 2023 to early 2025 and future planned fertility are higher among adults who WFH at least one day a week and, for couples, higher yet when both partners do so. Estimated lifetime fertility is greater by 0.32 children per woman when both partners WFH one or more days per week as compared to the case where neither does. The implications for national fertility rates differ across countries due mainly to large differences in WFH rates. In a complementary analysis using other U.S. data, one-year fertility rates in the 2023-2025 period rise with WFH opportunities in one's own occupation and, for couples, in the partner's occupation.

Urbanisation is transforming population health, yet globally comparable evidence on adult health differences between urban and rural areas remains limited. We analysed repeated cross-sectional data from the Gallup World Poll (2006–2023), covering 2.4 million adults in 167 countries. Using weighted linear probability models, we compared self-reported health within country and year.

Across most countries, urban residents reported better health than rural residents, with a consistent gradient from rural areas to villages, suburbs, and large cities. The positive urban–rural gap appeared across demographic and national contexts and persisted within income quartiles, although income–health gradients within places were larger. The gap widened over time and was only modestly reduced after adjusting for age, education, and income. These findings indicate a durable spatial health gradient alongside substantial socioeconomic inequality within settlements.

Accurate gestational dating is central to obstetric decision-making: it determines preand post-term classification, guides induction at clinical thresholds, and can shape important perinatal health outcomes for human capital formation. This paper examines Sweden’s implementation of ultrasound-based gestational dating standardization (UTS) and whether a technology intended to improve pregnancy dating inadvertently introduced sex-specific measurement error that shifted management at the post-term cutoff. The mechanism is straightforward: fetal-size reference charts used for ultrasound dating are typically sexneutral, but female fetuses are, on average, slightly smaller at a given actual gestational age. Estimating the causal effect of being dated by UTS is challenging because early ultrasound usage was not randomly assigned. I address this with an instrumental-variables strategy that exploits hospital-level practice intensity using the Swedish Medical Birth Register linked to administrative records. I study immediate neonatal outcomes, delivery practices, and longer-run humancapital proxies measured through standardized school grades.