Wenna Xi

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Welcome to My Homepage!

I am Instructor in the Division of Biostatistics in the Department of Population Health Sciences (formerly known as the Department of Healthcare Policy and Research) at Weill Cornell Medicine. I received my PhD degree in Biostatistics in 2019 from The Ohio State University (dissertation) and completed my postdoctoral training in Mental Health Data Science at Weill Cornell.

My research these days mostly focuses around using big data (e.g., EHR, insurance claims data) to study mental health, especially disparities in youth mental health care. I recently received a K99 award on studying risk and protective factors for Black youth suicide and suicidal thoughts and behaviors (K99 MH130713).

My doctoral dissertation focuses on the statistical analysis of co-location networks, which are a special type of two-mode networks where ties are only defined between the nodes of different modes. In the case of co-location networks, nodes represent individuals and geographic locations and ties indicate that the individual visits the location. I use co-location networks to study routine activity patterns of individuals within an urban setting. The primary objective, in particular, is to detect ecological communities of individuals based on the set of locations where they spend time, instead of their locations of residence. I use two approaches to achieve the goal: 1) latent Dirichlet allocation (LDA), a well-developed method in text data mining, and 2) hierarchical Bayesian non-negative matrix factorization (NMF), which is similar to LDA but can be adapted to make use of sparse finite mixture techniques to automatically determine the number of communities in a co-location network.

Besides my dissertation research, I was a Graduate Research Associate (GRA) at Ohio State’s Center of Excellence in Regulatory Tobacco Science (OSU-CERTS) from September 2015 to August 2018, where I provided data management and statistical analysis for two ongoing surveys: the Buckeye Teen Health Study (BTHS) and the Tobacco User Adult Cohort (TUAC).

Contact Information

Department of Population Health Sciences
Weill Cornell Medicine
LA009, 402 E 67th St
New York, NY 10065
T: (646)962-5641
wex4002@med.cornell.edu