At the intersection of physical sciences and policy, our researchers work to find solutions for hunger, environmental degradation, emerging energy markets and more.
Research Spotlight
Economic Policy Challenges Facing California's Next Governor: Electricity Policy Reform
Because Californians are likely to want to continue to lead the energy transition, the relevant policy design question is: How can the state achieve these low-carbon energy goals in a more cost- effective manner?
Climate Change is Increasing the Risk of Extreme Autumn Wildfire Conditions Across California
The climate model analyses presented here suggest that continued climate change will further amplify the number of days with extreme fire weather by the end of this century, though a pathway consistent with the UN Paris commitments would substantially curb that increase.
Sight for Sorghums: Comparisons of Satellite- and Ground-Based Sorghum Yield Estimates in Mali
Leveraging a survey experiment in Mali, this study uses plot-level sorghum yield estimates, based on farmer reporting and crop cutting, to construct and evaluate estimates from three satellite-based sensors.
Proceedings of the National Academy of Sciences (PNAS),
June 6, 2025
The number of acutely food insecure people worldwide has doubled since 2017, increasing demand for early warning systems (EWS) that can predict food emergencies. Advances in computational methods, and the growing availability of near-real time remote sensing data, suggest that big data approaches might help meet this need. But such models have thus far exhibited low predictive skill with respect to subpopulation-level acute malnutrition indicators. We explore whether updating training data with high frequency monitoring of the predictand can help improve machine learning models’ predictive performance with respect to child acute malnutrition by directly learning the dynamic determinants of rapidly evolving acute malnutrition crises. We combine supervised machine learning methods and remotely sensed feature sets with time series child anthropometric data from EWS’ sentinel sites to generate accurate forecasts of acute malnutrition at operationally meaningful time horizons. These advances can enhance intertemporal and geographic targeting of humanitarian response to impending food emergencies that otherwise have unacceptably high case fatality rates.
Achieving minimum dietary diversity (MDD), a crucial indicator of infant and young child diet quality, remains a challenge in rural China, especially for infants aged 6–11 months. This study examined the rate of MDD attainment in rural China, identified its determinants using the Capability, Opportunity, Motivation, and Behavior (COM-B) model and Bayesian network analysis, and estimated the potential impact of improving each modifiable determinant. A multi-stage sampling design selected 1328 caregivers of infants aged 6–11 months across 77 rural townships in China. Data were collected through a cross-sectional survey via in-person household interviews. Bayesian network analysis identified key factors influencing MDD attainment and their interrelationships, while Bayesian inference estimated MDD attainment probabilities. Results showed that only 22.2 % of the sample infants attained MDD. Bayesian network analysis revealed that caregiver knowledge (a proxy of capability), self-efficacy and habits (proxies of motivation), and infant age directly influenced MDD attainment. Social support (a proxy of opportunity) indirectly promoted MDD attainment by boosting self-efficacy and habit. Notably, simultaneous improvements in knowledge, self-efficacy, and habit could increase MDD attainment by 17.6 %, underscoring the potential effectiveness of interventions focused on enhancing caregiver capability and motivation. The critically low MDD attainment rate among rural Chinese infants highlights the urgent need for targeted interventions. Strategies should prioritize enhancing caregiver feeding knowledge, self-efficacy, and habit formation to improve infant dietary diversity. Addressing these key factors could substantially boost MDD attainment in rural China.
The latest crisis was triggered by a terrorist attack at Pahalgam on April 22, which was especially provocative — and likely calculated to be so — by targeting specifically Hindu men for point-blank execution.
Journal of Medical Internet Research,
May 15, 2025
Background: The content of children’s screen exposure and interactive coviewing with caregivers are important determinants of early childhood development (ECD) that have been overlooked in past research in resource-limited rural regions. Given the prevalence of digital devices and diverse digital content today, determining screen use practices that minimize the negative impacts on children’s development is crucial for promoting healthy screen use among children.
Objective: This study aims to examine screen exposure among children aged <3 years in rural China and investigate its relationship with ECD outcomes, focusing on duration, content, coviewing, and interaction.
Methods: The sample includes all children aged between 6 and 26 months and their primary caregivers residing in the study area. A survey of screen exposure and household characteristics was conducted for 1052 eligible households. Caregivers reported the duration of screen exposure, defined as the average daily screen time over the past month; the content of exposure, defined by the time spent on educational and child-friendly content; and the caregiver’s presence and interaction with the child during exposure. ECD outcomes were evaluated using the third edition of the Bayley Scales of Infant and Toddler Development assessment scale and the Brief Infant Toddler Social Emotional Assessment. Ordinary least squares regression, logistic regression, and chi-square tests were conducted.
Results: In total, 28.23% (297/1052) of the children in our sample were first exposed to screens before the age of 12 months. Children exposed to screens had an average daily screen time of 27.57 (SD 38.90) minutes. Children who were exposed to screens before the age of 12 months and those who had longer screen time between the ages of 12 and 18 months were more likely to be at risk of motor developmental delays. Children exposed to educational content for >15 minutes on a daily basis had fewer social-emotional or behavioral problems than those with no screen exposure and a lower risk of delay in motor skills development than those exposed to educational content for <15 minutes on a daily basis. Caregiver interaction during screen exposure was associated with a lower risk of cognitive and language delays and better socioemotional skills.
Conclusions: The type of content viewed and how caregivers engaged in children’s screen time were strongly associated with ECD outcomes. Guiding parents to select educational content for their children and engaging in interactive coviewing may better protect children from the negative effects of screen exposure. The findings complement conclusions regarding the impact of screen exposure on ECD in resource-limited rural areas.
Using reading performance data from a randomized controlled trial of 5224 fifth-grade students in East China, this paper provides a novel test of the hypothesis that evoking a gender stereotype creates gender gaps in education through self-fulfilling prophecies. We found that without intervention, boys performed worse than girls did in reading tests. Evoking a gender stereotype by indicating the expected outperformance of girls over boys in reading had a significantly negative effect on boys and an insignificant effect on girls. As a result, the net effect on the gender gap in reading performance was economically important but statistically insignificant. We also found evidence that increased anxiety was likely the underlying mechanism. Finally, a heterogeneous analysis showed that boys from environments with biased gender role beliefs were more susceptible to the intervention.
National Bureau of Economic Research (NBER),
May 5, 2025
China’s total fertility rate declined very little following implementation of the One Child Policy (OCP) in 1979/1980, but then fell sharply, by more than one-third, during the early 1990s. In this paper, we propose that strengthening bureaucratic incentives under the “One Vote Veto” (OVV) policy, which strictly prohibited career promotion for adherence failure, was necessary for more “effective” implementation of the OCP—and for its delayed impact on fertility. We use provincial variation in OVV implementation to estimate event study regression inputs needed to build actual and counterfactual sequential multi-decrement fertility life tables, finding that the policy explains 46% of China’s total fertility rate decline during the 1990s, driving it below replacement level. Use of intrauterine devices (IUDs, the most prevalent form of modern contraception in China) that was “recommended” by party officials increased by 133% under the policy, a relative increase more than four times as large as the increase in “voluntary” use. Overall, our paper suggests that population policy made a larger contribution to low fertility in China than suggested by past research. More generally, our paper highlights the central role of aligning bureaucratic incentives with public policy objectives, even in a centrally-planned economy like China’s.
Part of "Deliberative Approaches to Inclusive Governance: An Essay Series Part of the Democratic Legitimacy for AI Initiative," produced by the Centre for Media, Technology and Democracy.
This paper examines how power lawyers shape judicial and economic outcomes by studying the “revolving door” between judges and lawyers in China’s judicial system—namely, former judges who quit the bench to practice law. In otherwise identical lawsuits, revolving-door lawyers deliver 8−23% higher win rate for their clients. Their performance in home versus away courts suggests these gains stem from both “know how” and “know who.” We extend the theoretical framework of Dewatripont and Tirole (1999) to show that revolving-door lawyers create countervailing forces in society: they enhance judicial decision-making through evidence and reasoning, but also exploit strategic arguments and connections to bias outcomes in favor of their clients. We estimate a structural model of the judicial process to quantify these trade-offs and find that increasing the supply of power lawyers can have a non-monotonic effect on equilibrium judicial quality.
Federal IT is a worthy target for Musk and his team of efficiency hackers. It’s overpriced with various estimates pegging the government’s costs at two to four.