Study examines the link between human development and fertility in the United States
Birth rates are declining in developed countries around the world, a trend often linked with economic and human progress. A study led by Henrik-Alexander Schubert of the MPIDR reveals that fertility rates can actually increase at high levels of human development, a pattern known as the "J-shape." However, this relationship appears to have shifted after 2010, possibly influenced by the 2007/08 economic recession and changing societal values.
Birth rates are falling in the world's highly developed countries. In the 20th century, fertility decline has been associated with advancements in economic and human development, leading to the widely held belief that progress and fertility are inversely related. Today, over half of the world's population lives in regions where the fertility rate is below the replacement level. In highly developed countries, this low rate was long considered irreversible. A recent study by Henrik Alexander Schubert of the MPIDR, alongside colleagues Christian Dudel, Marina Kolobova and Mikko Myrskylä, analyzes the relationship between human development and fertility in the United States between 1969 and 2020. The data reveals a familiar J-Shape, but also brought surprises.
„The research uncovers a dynamic connection between fertility and human development. "Initially, as human development advances, fertility declines. This is described and captured by the theory of demographic transition. However, at higher levels of human development this trend reverses, and progress in development increases fertility. Thus, at very advanced levels of development, fertility rates rebound to some degree with progress in development. The reversal of this fertility decline is closely tied to progress in gender equality in households and a positive economic outlook. Recently, however, this relationship seems to have decoupled.", explains Henrik Schubert.
The figure shows the relationship between development indicators and female total fertility rate (TFR), by US regions. The x-axes reflect the various development indicators (Human Development Index and Human Life Indicator).
© MPIDR
While the results confirm that fertility can rebound at advanced stages of development, this finding is limited to the period before 2010 and is consistent across different measures of fertility and societal development. Since then there is a linear decline in fertility across all U.S. states, regardless of their individual level of development. This shift suggests a possible structural break, coinciding with the economic recession in the United States in 2007/08, which subsequently led to a ten-year decline in fertility.
The study revises the earlier J-Shape thesis by Mikko Myrskylä, now director of the Max Planck Institute for Demographic Research (MPIDR). In 2009 he published the paper "Advances in development reverse fertility declines" showing that in countries with a high Human Development Index (HDI), further development reverses the fertility decline. Myrskylä coined the term "J-Shape," a curve in the fertility graph that starts at a very high level, then falls steeply before rising slowly to form an inverse J. The curve represents the decline and recovery of fertility in highly developed countries. The original study has been and continues to be widely discussed. "Our finding re-affirms the J-shape hypothesis, but also points to the decoupling of fertility and human development in recent years", explains Schubert.
"Our study indicates that progressive policies promoting human development, economic stability and gender equality can effectively boost fertility", Schubert adds. A stable economic and social situation along with positive future prospects encourages couples to pursue their fertility intentions. This is particularly relevant because some countries, such as Hungary and South Korea, have recently adopted pronatalist policies aimed at promoting traditional family structures. However, these policies have yet to have a measurable impact on fertility rates. Instead, policies that promote human development, economic opportunities and gender equality in households have the potential to increase fertility in the long run.
