Is low fertility really an economic threat?

International Institute for Applied Systems Analysis

FacebookXLinkedInWeChatBlueskyMessageWhatsAppEmail

In their piece, published in Nature Human Behaviour, IIASA Distinguished Emeritus Research Scholar Wolfgang Lutz and IIASA Senior Researcher Guillaume Marois, who is also an associate professor at the Asian Demographic Research Institute of the Shanghai University, respond to political and public concern over declining birth rates in highly developed countries. While low fertility is increasingly framed as a crisis, associated with population ageing, labor shortages, and fiscal pressure, the authors argue that this narrative is based on outdated assumptions that no longer reflect current demographic realities.A central motivation for the paper was the widespread belief based on earlier studies that fertility would recover as human development continues. However, using the most recent data up to 2023, the authors demonstrate that this pattern has reversed. Today, the global cross-sectional relationship is clearly negative: the higher a country’s Human Development Index, the lower its fertility tends to be.

“This finding came as a surprise to much of the demographic community,” says Marois. “Even countries once considered models for balancing work and family life, such as the Nordics, have experienced unexpectedly steep fertility declines. The idea that development alone will bring fertility back up simply doesn’t hold anymore.”

The commentary also questions the normative status of replacement-level fertility, often defined as 2.1 children per woman. This benchmark, the authors argue, is an artificial construct that only leads to long-term population stability under unrealistic assumptions, notably the absence of further mortality decline. More importantly, population stability does not automatically translate into economic or social wellbeing.

Instead, the authors emphasize that economic sustainability depends more on population structure than on population size. Higher levels of education, increased labor force participation, and rising productivity can offset – and even outweigh – the effects of having fewer births. Lower fertility can enable greater investment per child, strengthening human capital and innovation while reducing dependency burdens over the coming decades.

The policy implications are clear. While pro-natalist measures can improve family wellbeing, increasing fertility should not be their main objective, as their impact on fertility is typically modest and higher fertility does not necessarily improve economic wellbeing. Governments should instead adapt social security, labor market, and pension systems to the reality of sustained low fertility, while strengthening investments in education and productivity. This shift is particularly relevant for countries such as South Korea, China, and Japan, which currently record some of the world’s lowest fertility rates and face especially intense political pressure to raise birth numbers.

“Our message is not that low fertility is inherently good or bad,” concludes Lutz. “There is no single ‘ideal’ fertility level that guarantees prosperity. Instead of trying to push birth rates back to an arbitrary target, governments should focus on adapting  social security  systems to the changing demographic realities and invest strongly in education and productivity. Under those conditions, societies can thrive even with fewer births.”

 

Reference
Marois, G., Lutz, W. (2026). Low fertility may persist and could be good for the economy. Nature Human Behaviour DOI: 10.1038/s41562-026-02423-6

 

Researcher contact

Guillaume Marois
Senior Research Scholar
Multidimensional Demographic Modeling Research Group
Population and Just Societies Program
marois@iiasa.ac.at

Wolfgang Lutz
Distinguished Emeritus Research Scholar
Multidimensional Demographic Modeling Research Group
Population and Just Societies Program
IIASA Sherpa for Asia
Directorate - DG Department|
lutz@iiasa.ac.at

Press Officer
Bettina Greenwell
IIASA Press Office
Tel: +43 2236 807 282
greenwell@iiasa.ac.at

 

About IIASA:

The International Institute for Applied Systems Analysis (IIASA) is an international scientific institute that conducts research into the critical issues of global environmental, economic, technological, and social change that we face in the twenty-first century. Our findings provide valuable options to policymakers to shape the future of our changing world. IIASA is independent and funded by prestigious research funding agencies in Africa, the Americas, Asia, and Europe.

---

Journal

Nature Human Behaviour

DOI

10.1038/s41562-026-02423-6 

Article Title

Low fertility may persist and could be good for the economy

Article Publication Date

2-Mar-2026

 

Survival training in a safe space

University of Würzburg

FacebookXLinkedInWeChatBlueskyMessageWhatsAppEmail

Adaptation is essential for survival. Across species, it occurs over many generations through evolution and natural selection. Individual animals, however, can also adapt within their own lifetimes – through learning. For many species, humans included, this process is vital.

The challenge arises when adaptation must take place in a hazardous environment, such as when hunting dangerous prey. “In such cases, learning through exploration can pose a serious threat to a juvenile’s survival,” explains Dharanish Rajendra. He is a doctoral researcher working with Professor Chaitanya Gokhale, Chair of Computational and Theoretical Biology at Julius-Maximilians-Universität Würzburg (JMU).

One solution is parental care: adults create protected learning environments in which offspring can gradually approach the challenges of real life.

In a new publication, the two researchers use mathematical and computational models to investigate how such learning environments can be structured to promote successful adaptation.

Step by step towards competence

Many predators specialise in prey that represent a substantial risk for inexperienced hunters. Wolves take on elk and bison many times their size, pythons must subdue porcupines, and meerkats frequently prey on venomous scorpions.

These small mammals, native to southern Africa, live in colonies of up to 45 individuals and are well known for their complex social behaviour. To prepare their young for handling dangerous prey, adults proceed in stages: first offering dead scorpions, then scorpions with the sting removed, and only later presenting fully intact, dangerous prey once the juveniles have developed sufficient skill.

When protection goes too far

In their study, the researchers modelled this developmental transition using a two-phase learning framework, simulating the shift from a protected juvenile stage to an unprotected adult environment.

Their findings highlight a risk reminiscent of so-called “helicopter parenting”: if the learning environment is too safe, or differs too greatly from real conditions, maladaptation can occur. Individuals may reach adulthood insufficiently prepared and struggle to cope with genuine risks.

“What matters most for successful protected learning is that the environment remains sufficiently similar to reality,” says Chaitanya Gokhale. “A gradual increase in risk bridges the gap between a safe developmental space and the demands of the real world.”

The mathematics behind behaviour

To analyse these behavioural strategies, the researchers combined two complementary modelling approaches.

Dynamic programming was used to calculate the theoretically optimal strategy under different environmental conditions. Reinforcement learning was then employed to simulate how individuals acquire such strategies through trial and error.

Together, these methods show how an animal learns to weigh risks against rewards and how early-life experience shapes later performance.

“Our research provides a theoretical foundation for parental care strategies that have long been observed in nature, but whose underlying mathematical logic has remained unclear,” says Dharanish Rajendra. The findings contribute more broadly to our understanding of early-life learning in both animals and humans, as well as species-specific differences in parental care.

Because many species that provide extended parental care are also highly social, the researchers see promising directions for future work. In particular, they aim to investigate how protected developmental environments interact with social learning – learning through observing and drawing on the experiences of others.

---

Journal

Proceedings of the Royal Society B Biological Sciences

DOI

10.1098/rspb.2025.3111 

Article Title

Optimising play for learning risky behaviour

Article Publication Date

26-Feb-2026

 

New study maps 74 years of China’s medical education policy: A shift from segmentation to integration

Policy documents analysis from 1949–2023 reveals how China creates synergies between education and healthcare, while highlighting critical gaps

ECNU Review of Education

FacebookXLinkedInWeChatBlueskyMessageWhatsAppEmail

Published online on February 12, 2026, in ECNU Review of Education, the study was led by Professor Hongbin Wu of Peking University. The research applies policy tools theory to examine how government actors deploy policy instruments across different stages of medical education governance.

The findings show that China’s education–healthcare collaboration has undergone a gradual transformation from administratively segmented governance to increasingly coordinated system integration. Early reforms focused primarily on institutional restructuring and the establishment of specialized medical education systems. Over time, policy priorities expanded to include standardized clinical training, residency systems, and interministerial coordination. More recent reforms have placed stronger emphasis on aligning medical education with healthcare service delivery needs, reflecting a systemic shift toward workforce-oriented talent cultivation.

The study finds that the structure of policy tools deployed to promote education–healthcare synergies remains imbalanced. Environmental policy instruments—such as regulatory frameworks, accreditation systems, and governance directives—account for the largest share of policy interventions, followed by supply-side measures such as funding investments and infrastructure development. In contrast, demand-side tools, including workforce incentives, scale forecasting, and institutional motivation mechanisms, are comparatively underutilized. According to the researchers, this imbalance reflects a predominantly state-led governance model that prioritizes regulatory control and resource allocation, which may constrain institutional flexibility and endogenous innovation.

The analysis also highlights coordination challenges among major policy actors. China’s SEHS governance is jointly led by the Ministry of Education and the National Health Commission, alongside other central ministries. While this multi-actor framework enables comprehensive policy coverage, differences in institutional mandates and performance priorities create operational tensions. Education authorities tend to emphasize academic training quality and curriculum systems, whereas health authorities focus more heavily on clinical service capacity and workforce deployment.

Another key finding concerns insufficient alignment across the three stages of medical education: undergraduate education, graduate medical education, and continuing professional development. Policies governing these stages often function in parallel rather than as an integrated pipeline, resulting in duplicated training processes, extended certification cycles, and inefficient resource utilization.

“Our analysis shows that education–healthcare collaboration cannot be understood through single policies or isolated reforms,” the research team notes. “It is shaped by the interaction of policy tools, institutional actors, and governance stages over time.”

The study concludes that optimizing the integration of education and healthcare systems is essential for improving medical talent cultivation and ensuring sustainable healthcare workforce development. The findings offer timely policy insights for China and other countries seeking to strengthen cross-sector collaboration in health professions education.

 

Reference

DOI: https://doi.org/10.1177/20965311251403495

---

Journal

ECNU Review of Education

DOI

10.1177/20965311251403495 

Method of Research

Survey

Subject of Research

Not applicable

Article Title

Synergies Between Education and Healthcare Systems in China: A Three-Dimensional Analysis of 64 Policy Documents (1949–2023)

 

USF study: Gag grouper are overfished in the Gulf; this new tool could help

New research may assist resource managers who make tough decisions about the lengths of fishing seasons

University of South Florida

FacebookXLinkedInWeChatBlueskyMessageWhatsAppEmail

 

image: 

Various research projects aim to better understand the movement patterns and habitat use of gag groupers.

view more 

Credit: FWC Fish and Wildlife Research Institute

Anglers along the Gulf Coast have long prized the hard-fighting, mild-tasting gag grouper (Mycteroperca microlepis), but some may have been surprised over the past few years by shortened seasons for this desirable reef fish. Due to concerns about the population of the species, the gag season lasted just 41 days in 2023, 15 days in 2024, and 14 days in 2025 — far shorter than the six-month seasons in previous years.

A new paper by researchers from the University of South Florida (USF) and Florida Fish and Wildlife Conservation Commission (FWC) may assist resource managers who make tough decisions about the lengths of fishing seasons. A statistical model created by the researchers offered more accurate harvest predictions and explicit estimates of the probability of exceeding quotas for the 2025 gag season.

“Our approach provides a flexible tool to support decision making, particularly for vulnerable, highly targeted stocks,” the authors wrote in the paper published in the February issue of North American Journal of Fisheries Management.

Gag grouper has been called a “poster child” for the challenge of recovering heavily exploited fish stocks. Fishing pressure and environmental stressors led NOAA to declare gag in the Gulf to be overfished in 2009, meaning the population had fallen below the sustainable threshold. The population was carefully rebuilt by 2014, but was again determined to be impaired following a stock assessment in 2021. Stricter quotas and shorter seasons were implemented to help the population recover.

Complicating management efforts are gag’s migratory behaviors, spatial distribution, and biological trait known as protogynous hermaphroditism.

Gag are born as females and begin their lives in estuaries like Tampa Bay, moving further offshore as they age. Some of the fish undergo a sex change as they get older and the largest gag are often males. Many of these large males reside on offshore reefs for the remainder of their relatively long lives.

These habits can make it challenging for agencies to get an accurate pulse on the health of gag populations. In fact, the 2014 assessment that found the gag population had recovered in the Gulf, predicted that just 2-3 percent of that population was male (down from historic levels of about 17 percent). Research by FWC published in 2020 showed that current regulations were “not sufficient for the male population to recover to historic levels.”

To help better manage this vulnerable population, researchers from the USF College of Marine Science and the FWC’s Fish and Wildlife Research Institute teamed up to develop an alternative approach to traditional fisheries forecasting.

“Harvest rates have traditionally been predicted using historical data, but that approach can be unreliable as regulatory changes can impact the behavior of anglers,” said A. Challen Hyman, lead author of the paper and research scientist at the USF College of Marine Science Center for Environmental Analysis Synthesis and Application (CEASA), which leverages data to better inform environmental policy and management.

Hyman and his colleagues instead used a statistical model that was trained on data from the past decade and accounts for changes in angler behavior that result from regulatory decisions.

“Our model allowed us to not only get a more accurate prediction of harvest but also to quantify risk, meaning fisheries managers can make decisions based on the chance of exceeding the quota,” he said.

The risk tolerance of resource managers fluctuates in response to the vulnerability of a particular species. If the fish stock is impaired or depleted, managers tend to be more conservative. A healthy stock, on the other hand, may warrant a longer season.

Population health is weighed against economic and social considerations for coastal communities — for example, how might regulations impact the commercial fishing industry or prevent anglers from catching their favorite sportfish?

The statistical model developed by Hyman and his colleagues was trained on data gathered since 2015 including the length of seasons, the date seasons began, and whether seasons for other highly desired species, such as red snapper, were open simultaneously. It predicted that anglers had a 50 percent probability of hitting the 2025 annual catch target in 12 days. Preliminary data from federal and state agencies suggest that prediction was accurate, as the 14-day season recorded just under the annual catch target.

“These findings are significant because they demonstrate an approach to fisheries forecasting that’s more accurate, efficient, and reliable than traditional methods,” said Tom Frazer, dean of the College of Marine Science, director of CEASA, and co-author of the paper. “Our hope is that this model can inform decisions about the management of gag and other recreational species, and ensure that those decisions are based on the best available science. At the end of the day, this will benefit both fish and fishermen.”

The findings are of particular interest to the Fishery Management Council, which makes decisions about the length of seasons based on the risk of exceeding quotas.

Moving forward, the researchers aim to better understand how recent technological advances, economic factors, and the number of anglers on the Gulf Coast will affect fish stocks.

“More powerful motors and improved electronics mean anglers are able to cover more water and also find fish more quickly,” Hyman said. “Those changes coupled with a growing number of anglers are likely to have considerable consequences for the rate at which gag are harvested and total amount of fish that are being removed from the population.”

Gag grouper are a desirable reef fish that face considerable threats from overfishing.

Credit

FWC / Margaret Thompson

Journal

North American Journal of Fisheries Management

Method of Research

Data/statistical analysis

Subject of Research

Animals

Article Title

Leveraging statistical models to improve preseason forecasting and in-season management of a recreational fishery