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.
Stanford scholars are setting and expanding research agendas to analyze China’s economic development and its impact on the world. The newly launched Stanford Center on China’s Economy and Institutions — co-directed by SIEPR senior fellows Hongbin Li and Scott Rozelle — is supporting their work. In this SIEPR Policy Brief, Li and Rozelle outline the research underway by the new center's affiliates.
The sustainability of aquaculture has been debated intensely since 2000, when a review on the net contribution of aquaculture to world fish supplies was published in Nature. This paper reviews the developments in global aquaculture from 1997 to 2017, incorporating all industry sub-sectors and highlighting the integration of aquaculture in the global food system. Inland aquaculture—especially in Asia—has contributed the most to global production volumes and food security. Major gains have also occurred in aquaculture feed efficiency and fish nutrition, lowering the fish-in–fish-out ratio for all fed species, although the dependence on marine ingredients persists and reliance on terrestrial ingredients has increased. The culture of both molluscs and seaweed is increasingly recognized for its ecosystem services; however, the quantification, valuation, and market development of these services remain rare. The potential for molluscs and seaweed to support global nutritional security is underexploited. Management of pathogens, parasites, and pests remains a sustainability challenge industry-wide, and the effects of climate change on aquaculture remain uncertain and difficult to validate. Pressure on the aquaculture industry to embrace comprehensive sustainability measures during this 20-year period have improved the governance, technology, siting, and management in many cases.
Recent years have witnessed rapid growth in satellite-based approaches to quantifying aspects of land use, especially those monitoring the outcomes of sustainable development programs. Burke et al. reviewed this recent progress with a particular focus on machine-learning approaches and artificial intelligence methods. Drawing on examples mostly from Africa, they conclude that satellite-based methods enhance rather than replace ground-based data collection, and progress depends on a combined approach.
International Journal of Environmental Research and Public Health,
March 6, 2021
The home language environment is critical to early language development and subsequent skills. However, few studies have quantitatively measured the home language environment in low-income, developing settings. This study explores variations in the home language environment and child language skills among households in poor rural villages in northwestern China. Audio recordings were collected for 38 children aged 20–28 months and analyzed using Language Environment Analysis (LENA) software; language skills were measured using the MacArthur–Bates Mandarin Communicative Developmental Inventories expressive vocabulary scale. The results revealed large variability in both child language skills and home language environment measures (adult words, conversational turns, and child vocalizations) with 5- to 6-fold differences between the highest and lowest scores. Despite variation, however, the average number of adult words and conversational turns were lower than found among urban Chinese children. Correlation analyses did not identify significant correlations between demographic characteristics and the home language environment. However, the results do indicate significant correlations between the home language environment and child language skills, with conversational turns showing the strongest correlation. The results point to a need for further research on language engagement and ways to increase parent–child interactions to improve early language development among young children in rural China.
The New England Journal of Medicine ,
March 3, 2021
Now that a third COVID-19 vaccine has been given emergency-use authorization, Michelle Mello and colleagues ask whether individuals should be able to choose which vaccine they receive.
Background: The educational resources that parents provide at home are crucial to their children’s development. In this study, we focused on home reading environment, a key contributor to success rates regarding the mastery of reading skills. We aimed to investigate students’ home reading environments and examine its effect on the reading development of primary school students in rural China. Methods: We draw on a dataset composed of 10,740 randomly selected primary school students and their households in rural areas of Jiangxi province in China. Surveys were administered by trained enumerators in May 2015. Results: The results show that students exhibited quite poor reading environments and reading outcomes. Specifically, we found the majority of the rural students lacked reading and learning resources in the context of their families and their parents did not enjoy reading or support their children’s reading. Moreover, our regression analysis documented students with poorer home reading environments are more likely to have worse reading performance. Conclusion: Our study supports the significance of the home reading environment in the reading development of students in the upper elementary grades in rural China. Furthermore, the results suggest that the home reading environments of rural Chinese students must be improved.
Universities contribute to economic growth and national competitiveness by equipping students with higher-order thinking and academic skills. Despite large investments in university science, technology, engineering and mathematics (STEM) education, little is known about how the skills of STEM undergraduates compare across countries and by institutional selectivity. Here, we provide direct evidence on these issues by collecting and analysing longitudinal data on tens of thousands of computer science and electrical engineering students in China, India, Russia and the United States. We find stark differences in skill levels and gains among countries and by institutional selectivity. Compared with the United States, students in China, India and Russia do not gain critical thinking skills over four years. Furthermore, while students in India and Russia gain academic skills during the first two years, students in China do not. These gaps in skill levels and gains provide insights into the global competitiveness of STEM university students across nations and institutional types.
Journal of Development Effectiveness,
February 26, 2021
This paper examines the external validity of health intervention by comparing the impacts of providing free eyeglasses on the educational performance of nearsighted children in two settings: rural public schools in Western China and urban private migrant schools in Eastern China. The intervention significantly improves educational outcomes by 0.14 standard deviations in math in rural public schools but not in private migrant schools. The difference in measured impacts is due in part to lower quality schooling in migrant schools in Eastern China. Our findings show that only when school is providing a quality education, health interventions might increase student learnings.
Science of The Total Environment,
February 26, 2021
In the absence of a federal geologic repository or consolidated, interim storage in the United States, commercial spent fuel will remain stranded at some 75 sites across the country. Currently, these include 18 “orphaned sites” where spent fuel has been left at decommissioned reactor sites.
