research

2025

1. arXiv

   Small Area Estimation of Fertility in Low‐and Middle‐Income Countries

   Yunhan Wu and Jon Wakefield

   arXiv preprint, 2025

   Bib Preprint

   @article{Wu2025Fertility,
     author = {Wu, Yunhan and Wakefield, Jon},
     title = {Small Area Estimation of Fertility in Low‐and Middle‐Income Countries},
     year = {2025},
     preprint = {https://arxiv.org/abs/2507.03584},
     journal = {arXiv preprint arXiv:2507.03584},
   }

2. arXiv

   sae4health: An R Shiny Application for Small Area Estimation in Low‐and Middle‐Income Countries

   Yunhan Wu, Qianyu Dong, Jieyi Xu, and 2 more authors

   arXiv preprint, 2025

   Bib Preprint

   @article{Wu2025sae4health,
     author = {Wu, Yunhan and Dong, Qianyu and Xu, Jieyi and Li, Zehang Richard and Wakefield, Jon},
     title = {sae4health: An R Shiny Application for Small Area Estimation in Low‐and Middle‐Income Countries},
     year = {2025},
     preprint = {https://arxiv.org/abs/2505.01467},
     journal = {arXiv preprint arXiv:2505.01467},
   }

3. arXiv

   Small Area Estimation of Education Levels in Low‐and Middle‐Income Countries

   Yunhan Wu, Ameer Dharamshi, and Jon Wakefield

   arXiv preprint, 2025

   Bib Preprint

   @article{Wu2025Education,
     author = {Wu, Yunhan and Dharamshi, Ameer and Wakefield, Jon},
     title = {Small Area Estimation of Education Levels in Low‐and Middle‐Income Countries},
     year = {2025},
     journal = {arXiv preprint arXiv:2502.07946},
     preprint = {https://arxiv.org/abs/2502.07946},
   }

4. arXiv

   Toward a Principled Workflow for Prevalence Mapping Using Household Survey Data

   Qianyu Dong, Yunhan Wu, Zehang Richard Li, and 1 more author

   arXiv preprint, 2025

   Bib Preprint

   @article{Dong2025Workflow,
     author = {Dong, Qianyu and Wu, Yunhan and Li, Zehang Richard and Wakefield, Jon},
     title = {Toward a Principled Workflow for Prevalence Mapping Using Household Survey Data},
     year = {2025},
     preprint = {https://arxiv.org/abs/2504.16435},
     journal = {arXiv preprint arXiv:2504.16435},
   }

2024

1. JRSSA

   Modelling urban/rural fractions in low- and middle-income countries

   Yunhan Wu and Jon Wakefield

   Journal of the Royal Statistical Society Series A: Statistics in Society, Jan 2024

   Abs DOI Bib

   In low- and middle-income countries, household surveys are the most reliable data source to examine health and demographic indicators at the subnational level, an exercise in small area estimation. Model-based unit-level models are favoured for producing the subnational estimates at fine scale, such as the admin-2 level. Typically, the surveys employ stratified 2-stage cluster sampling with strata consisting of an urban/rural designation crossed with administrative regions. To avoid bias and increase predictive precision, the stratification should be acknowledged in the analysis. To move from the cluster to the area requires an aggregation step in which the prevalence surface is averaged with respect to population density. This requires estimating a partition of the study area into its urban and rural components, and to do this we experiment with a variety of classification algorithms, including logistic regression, Bayesian additive regression trees, and gradient boosted trees. Pixel-level covariate surfaces are used to improve prediction. We estimate spatial HIV prevalence in women of age 15–49 in Malawi using the stratification/aggregation method we propose.

   @article{urbanruralmodeling,
     author = {Wu, Yunhan and Wakefield, Jon},
     title = {Modelling urban/rural fractions in low- and middle-income countries},
     journal = {Journal of the Royal Statistical Society Series A: Statistics in Society},
     volume = {187},
     number = {3},
     pages = {811-830},
     year = {2024},
     month = jan,
     issn = {0964-1998},
     doi = {10.1093/jrsssa/qnae003},
     url = {https://doi.org/10.1093/jrsssa/qnae003},
   }

2. Sci. Total Environ.

   Integrating traffic pollution dispersion into spatiotemporal NO2 prediction

   Yunhan Wu, Jianzhao Bi, Amanda J Gassett, and 3 more authors

   Science of The Total Environment, Jan 2024

   DOI Bib

   @article{wu2024integrating,
     title = {Integrating traffic pollution dispersion into spatiotemporal NO2 prediction},
     author = {Wu, Yunhan and Bi, Jianzhao and Gassett, Amanda J and Young, Michael T and Szpiro, Adam A and Kaufman, Joel D},
     journal = {Science of The Total Environment},
     year = {2024},
     volume = {925},
     pages = {171652},
     doi = {10.1016/j.scitotenv.2023.171652},
   }

2021

1. Report

   Spatial modeling for subnational administrative level 2 small-area estimation

   Yunhan Wu, Zehang Richard Li, Ben Mayala, and 9 more authors

   DHS Spatial Analysis Reports No. 21, Jan 2021

   Bib HTML PDF

   @article{wu:etal:21,
     title = {Spatial modeling for subnational administrative level 2 small-area estimation},
     institution = {{ICF} International},
     journal = {DHS Spatial Analysis Reports No.~21},
     author = {Wu, Yunhan and Li, Zehang Richard and Mayala, Ben and Wang, Houjie and Gao, Peter and Paige, Johnny and Fuglstad, Geir-Arne and Moe, Caitlin and Godwin, Jessica and Donohue, Rose and Croft, Trevor and Wakefield, Jon},
     year = {2021},
   }

2. High prevalence of diabetes mellitus and mental illness among victims of sudden death.

   Murrium I Sadaf, Marie Caldwell, Laura A Young, and 6 more authors

   Southern Medical Journal, Jan 2021

   DOI