Celebrating our current postdocs

In observance of National Postdoc Appreciation Week, we thank our two current postdoctoral research fellows for their contributions to our department.headshots Jia Li and Leila Azinfar

Jia Li (left) previously studied at Xiamen University and Shanghai Technology University as well as the German Heart Centre in Munich before joining our department four years ago. Her projects have included working on a single-cell multi-resolution marker-based annotation method (scMRMA), a single-cell and spatial transcriptomic clustering method (aKNNO), and single-cell analysis of Crohn's disease. Her accomplishments include a first-authored paper on scMRMA in Nucleic Acids Research.

Leila Azinfar (right) joined our department in April with a PhD in bioengineering from Missouri and master's degrees from Shaheed Behest University of Medical Sciences (biomedical engineering) and Amirkabir University of Technology (radiological systems engineering). At Vanderbilt, she works with Amir Asiaee, primarily on the causal effect estimation of regulatory molecules. Her publications include a first-authored paper on high-resolution imaging in the Journal of Biophotonics 




Vanderbilt Biostatistics to host ASA traveling short course

On October 20, we will host the short course “From R Markdown to Quarto” with the Middle Tennessee chapter of the American Statistical Association (ASA). This one-day course is designed for those who want to take their R Markdown skills and expertise and apply them in Quarto, the next generation of R Markdown. Quarto is an open-source scientific and technical publishing system that offers multilingual programming language support to create dynamic and static documents, books, presentations, blogs, and other online resources. The course will be taught by Mine Çetinkaya-Rundel, professor of the practice of statistical science at Duke University. It will be held in Light Hall from 9:30 a.m. to 5:00 p.m. See the course webpage for details and registration.

Members of the Middle Tennessee chapter of the ASA receive discounted registration. The cost is $70 for student members; $90 for student non-members; $140 for non-student members; and $180 for non-student non-members. Visit the ASA Chapters page to join or renew your membership.

Assistant professor and director of graduate recruitment Simon Vandekar is the president of the ASA's Middle Tennessee chapter. Other chapter officers from our department include assistant professor Amber Hackstadt, associate professor Robert Johnson, and associate professor Rameela Raman.

Course instructor Mine Çetinkaya-Rundel

Vanderbilt Biostatistics at JSM 2023

The 2023 Joint Statistical Meetings, which convene in Toronto this Saturday, August 5, are expected to bring together more than five thousand attendees from 52 countries, with the theme of "One Community: Informing Decisions and Driving Discovery." We are proud of the department members and alumni who will be sharing their work, networking with current and future collaborators, contributing to section and conference planning meetings, and participating in other research and professional service activities. This year's conference program includes the following:

Saturday, August 5–Sunday, August 6

Regression modeling strategies: two-day course taught by professor Frank Harrell. 

Monday, August 7

The ubiquitous Other in biomedical research: Alternatives to simply pooling racial groups with small sample sizes: topic-contributed session with research assistant professor Lauren Samuels as a panelist. 8:30 a.m.

A two-stage least squares-based approach for assessing the role of engagement in text interventions: contributed speed presentation by PhD student Jamie Joseph. Co-authored by assistant professor Andrew Spieker. 8:30 a.m.

Robust Effect Size Index analysis using RESI R package: contributed speed presentation by PhD student Megan Jones. Co-authored by PhD student Kaidi Kang and assistant professor Simon Vandekar. 8:30 a.m.

Design and analysis strategies with "secondary" use data: topic-contributed paper presented by assistant professor Ran Tao. 8:55 a.m.

Longitudinal analysis of HIV antiretroviral therapy effects on weight gain: topic-contributed paper presented by assistant professor Andrew Spieker. Co-authored by biostatistician Tan Ding, biostatistician Caroline Birdrow, and professor Bryan Shepherd. 9:35 a.m.

Total, between- and within-cluster Spearman's rank correlations for clustered data: contributed paper presented by PhD student Shengxin Tu. Co-authored by Chun Li (University of Southern California) and professor Bryan Shepherd. 10:05 a.m.

Rosenbaum & Rubin’s Propensity Score: Impact, introspection and discussion 40 years later: invited session with alumna Lucy D'Agostino McGowan as a panelist. 10:30 a.m.

Application of closed-form gamma mixture model in mxIF cell gating: contributed paper presented by PhD student Jiangmei (Ruby) Xiong. Co-authored by Eliot McKinley (GSK), research associate professor of surgery Joseph Roland, research professor of medicine Martha Shrubsole, professor of cell and developmental biology and surgery Ken Lau, and assistant professor of biostatistics Simon Vandekar. 11:05 a.m.

Improving reproducibility in neuroimaging studies: contributed papers session chaired by assistant professor Simon Vandekar. 2:00 p.m.

Study features impacting replicability of brain-wide association studies: contributed paper presented by PhD student Kaidi Kang. Co-authored by Jakob Seidlitz (Penn), Richard Bethlehem (Cambridge), Aaron Alexander-Block (Penn), and Simon Vandekar. 3:05 p.m.

At the Teaching Statistics in Health Sciences mixer, alumna Lucy D'Agostino McGowan will receive their Young Investigator Award.

Tuesday, August 8

Overcoming microbial and experimental design compositionality to test model-free variable importance: contributed paper co-authored by assistant professor Siyuan Ma. 9:50 a.m. 

Optimal multi-wave validation of secondary use data with outcome and exposure misclassification: David P. Byar Early Career Award presentation by alumna Sarah Lotspeich. Co-authored by Pamela Shaw (Kaiser Permanente), assistant professors Gustavo Amorim and Ran Tao, and professor Bryan Shepherd. 9:55 a.m. 

Submodel approximation for risk prediction of a new patient with missing risk factors: contributed paper presented by PhD student Tianyi Sun. Co-authored by assistant professor of biomedical informatics Allison McCoy, associate professor of emergency medicine Alan Storrow, and associate professor of biostatistics Dandan Liu. 10:35 a.m.

Design and analysis of a multi-wave two-phase study that addresses data errors in a large observational HIV network: topic-contributed paper presented by professor Bryan Shepherd. 10:55 a.m.

Synergizing emerging methods for high-dimensional genomics and imaging data: topic-contributed paper session organized by assistant professor Jinyuan Liu and chaired by PhD student Kaidi Kang. 2:00 p.m.

A new paradigm for high-dimensional data: Distance-Based Semiparametric Ensembled (DBSE) framework for various diversity measures of microbiome composition: topic-contributed paper presented by assistant professor Jinyuan Liu. 2:05 p.m.

Probability-scale residuals for mixed-censored data: contributed paper co-authored by professor Bryan Shepherd. 2:35 p.m.


Wednesday, August 9

Statistical innovation in emerging fields of clinical research: Diversity, Equity and Inclusion (DEI); Learning Health System (LHS); Dissemination and Implementation Science (D&I): invited paper session organized by associate professor Dandan Liu and chaired by professor Qingxia (Cindy) Chen. 8:30 a.m.

Statistical methods to address challenges in implementing a EHR-based prediction model in emergency departments: invited paper presented by Dandan Liu. 9:50 a.m.


Thursday, August 10

Electronic Health Record capture and research use in the All of Us Research Program: invited paper presented by professor Qingxia (Cindy) Chen. Co-authored by Andrea Ramirez (NIH). 8:55 a.m.


For a guide to JSM presentation types, see their sessions guidelines. ...And, if you're a Vanderbilt trainee, staff, or faculty member, consider preparing a submission for JSM 2024, in Portland, Oregon. Proposals for invited talks are due September 7, short courses by September 30, topic-contributed proposals by December 7, computer tech workshops by January 15, and contributed papers by February 1. The theme for 2024 is "Statistics and Data Science: Informing Policy and Countering Misinformation." Also, JSM 2025 will be in Nashville, from August 2 through 7, as will the Institute of Mathematical Statistics' New Researchers Conference.




VN-BioStat Program concludes its first year

The Vanderbilt-Nigeria Biostatistics Training Program (VN-BioStat) has concluded its first year. The program, a collaboration between the Department of Biostatistics, the Vanderbilt Institute for Global Health, and Aminu Kano Teaching Hospital (AKTH) in Nigeria, aims to create a cohort of highly skilled Nigerian biostatisticians able to lead and supervise biostatistics activities for HIV research studies in West Africa. Professor Bryan Shepherd is one of the program's principal investigators.

The program’s inaugural fellows were Abdurrahman Abdulhamid (PhD student, mathematics) and Yusuf Ibrahim Ibrahim (PhD student, statistics) from Bayero University Kano in Nigeria. Ibrahim has been working with professor Robert Greevy to study various randomization strategies for a proposed clinical trial in Nigeria. He is also doing a large epidemiology study looking at cytopenia among people with HIV in West Africa. Abdurrahman is looking at the interaction between sickle cell disease and renal disease among people with HIV using a cross-sectional dataset from northern Nigeria. They will continue this work when they return to Nigeria this month while they complete their PhDs at their home institution.

Left: Abdurrahman Abdulhamid; Right: Yusuf Ibrahim Ibrahim

Left: Abdurrahman Abdulhamid; right: Yusuf Ibrahim Ibrahim

Below, Abdurrahman and Ibrahim share some of their experiences, insights, and advice for future fellows.

Abdurrahman Abdulhamid

Why did you want to join the program?

Assigned and provide analysis support to HIV-related research projects using AKTH data.

What did you like most about the program?

The unique responsibilities and project work associated with this program will absolutely help in developing the skills and experience required to work in a real job.

Did you learn anything that surprised you?

The whole idea of clinical trials, which is in every course in the six courses and weekly seminars, surprised me. Also, the professors are versed in excellent teaching methods.

What will you miss most about the program?

Resources that ease the study, and the prompt assistance from all the members of the Department of Biostatistics.

Do you have any advice for future fellows?

Try to harness the crude knowledge of the great scholars, and have helpful friends among the students.

What are you doing next?

To meet the target of the program by supporting projects at AKTH, and to continue and complete the project I started here and my PhD at Bayero University Kano.

Yusuf Ibrahim Ibrahim

Why did you want to join the program?

I applied this program because, in our country Nigeria, there is relatively a shortage of biostatisticians for the demand of biomedical research, resulting in generally overworked biostatisticians who work on multiple projects at the same time. This program will surely enable me to fill this gap.

What did you like most about the program?

It is great to study biostatistics in one of the focal points of biomedical research in the world. There are many brilliant and dedicated faculty here doing exciting research across a wide variety of critical areas. I admire all the staff of VUMC who are always ready to give you support whenever you need. I do like Nashville as a city. It’s a great place to live, as I am from tropics, however, I like the winter in Nashville. It’s nice seeing the snow for the first time. I will really miss the unique culture and hospitality of the people of Nashville.

Did you learn anything that surprised you?

Absolutely! I have had many wonderful experiences. For instance, before I came here, I looked at the R-software as a very complex and difficult thing to master. However, I was surprised by the ease I am now able to navigate many of its awesome features, courtesy of the fantastic teachers I have had here at Vanderbilt. I have been amazed by how they are able to make the seemingly difficult tasks so easy to master.  

What will you miss most about the program?

I will really miss the weekly seminar in the Department of Biostatistics where dedicated academics present interesting research in a wide range of topics and ideas. I will also miss the staff and students of the Biostatistics Department and the Institute for Global Health who supported me intellectually, morally, and socially. Moreover, I will miss playing soccer with Bryan, Dale and others. The time we spent together will forever remain in my memory. Furthermore, I will forever be grateful for the warm hospitality of the people of Nashville.

Do you have any advice for future fellows?

Learning at an advanced level in a new culture/environment could be quite challenging and Vanderbilt, despite its excellence and prestige among the world’s universities, is no exception. I would like to advise the future fellows to prepare well in advance and work hard when they arrive. I have come to realize that the harder I work, the more I like and find ease in what I do. Moreover, they should always be open to meeting and learning from other people.

What are you doing next?

In six months, I just have a modes plan of finishing my PhD in Nigeria, after that, I will continue doing research in Statistics, especially “Causal Inference.” In two years, I wish to come back to one of the academic institutions in the United State as postdoctorate student. In five years, I have more of visionary plan – professionally, I would like to lead my own research group in Nigeria.

Mario Davidson appointed associate vice chair of equity, diversity, and inclusion

Associate professor of biostatistics Mario Davidson has been appointed associate vice chair of equity, diversity, and inclusion (EDI) for the Department of Biostatistics. In this newly created senior leadership role, Davidson will assist vice chair of EDI Leena Choi with promoting awareness and fulfillment of EDI initiatives and standards across the department.

Mario Davidson and Leena Choi at 2022 department retreat

Mario Davidson and Leena Choi at the 2022 All-Department Retreat

Davidson, the 2022 winner of the Geoffrey David Chazen Award for Innovation in Medical Education, also serves on the board of the Academy for Excellence in Education and as invited faculty for the national Robert A. Winn Diversity in Clinical Trials Program

The vice chair of EDI position was created in 2020. Choi is the first and current appointee to this role. Under her direction, the department launched its Summer Internship Program for Underrepresented Undergraduates, which has just concluded hosting its second cohort. Choi has also actively provided guidance to department colleagues on EDI training and assessments, particularly in her role as a search committee member. Prospective faculty members must describe their efforts to encourage EDI in research, mentoring/teaching, and community outreach as part of their applications.

Going forward, Choi and Davidson are to be involved with every committee and task force in the department—including the recruitment and advancement of students, trainees, staff, and faculty—with the goal of maximizing opportunities for EDI and guarding against unconscious bias. The mandate for all department members is to be familiar with EDI principles and apply them to all activities. 

Additional initiatives in the department include the Diversity and Inclusion Application Fee Waiver for prospective PhD students (see the last section on our Application Process page) and a study group dedicated to Ethical Responsibilities Regarding Race in Research. PhD student Julia Thome is a recipient of the Provost’s Graduate Fellowship, which is offered by Vanderbilt University's Graduate School to incoming U.S. citizens and permanent residents from diverse backgrounds (a $10,000 stipend for five years, supplemental to any other funding offered to the scholar). Professor Bryan Shepherd is co-MPI of the VN-BioStat Training Program; associate professor Robert Greevy and assistant professor Peter Rebeiro serve on its training advisory committee. Abdurrahman Abdulhamid and Ibrahim Yusuf Ibrahim, the first two fellows, are reaching the end of their year in Nashville, and the next two trainees (Rukayya Alkassim and Safiya Sani) are expected to arrive in August.


Biostatistics faculty in Taipei, Sint-Michielsgestel, and Ann Arbor


On June 9, department chair Yu Shyr (third from left) delivered "Future of Investigational Medicine and Smart Data—What We Learned from ChatGPT" as a keynote during the 2023 Health+ Conference hosted by Taiwan's Bureau of Foreign Trade. (Photo via Taiwan's Ministry of Economic Affairs.)

Seven speakers giving thumbs up in front of a conference title screen,

From June 17 through June 23, Shyr is serving as invited faculty in the 2023 EORTC-ESMO-AACR Workshop on Methods in Clinical Cancer Research (MCCR) in the Netherlands. Shyr has been involved with MCCR workshops since 2004 and will be speaking on "Novel Study Design and Analysis for Integrating Multi-omics Technologies for Early Detection of Cancer" at the 2023 ESMO Asia Congress this December in Singapore.

Assistant professors Jinyuan Liu and Panpan Zhang were invited speakers at the 2023 ICSA Applied Statistics Symposium, which was in Ann Arbor last week. Zhang organized and chaired "Statistical and Machine Learning Methods with Applications to Neurodegenerative Diseases" on June 13, and presented "A Covariate-Dependent Multi-Layer Network Model for Classification Analysis in Neuroimaging" on June 14. Liu presented "Edge: Ensembled Distance-Based Generalized Semiparametric Estimation for Between-Subject Attributes in Longitudinal Microbiome Data" on June 13.

This week both Liu and Zhang are at WNAR in Alaska as invited session organizers and speakers. See the conference website for more about their presentations, and our Upcoming Presentations page for more meetings and workshops where they and other colleagues will be representing Vanderbilt Biostatistics.


Biostatistics faculty and students at NESS and CFAR

This past week, presentations by our faculty and students included the following:

June 3–6, 2023 - New England Statistics Symposium (NESS), Boston

  • Panpan Zhang, "Recent Advances in Neuroimaging Data Integration and Analysis" - invited session organizer (session chaired by Siyuan Ma)
  • Kaidi Kang, "Double Anchoring Events Based Sigmoidal Mixed Model for Alzheimer’s Disease Progression Modeling" - student paper presenter (paper co-authored by Panpan Zhang and Dandan Liu)

June 5–6, 2023 - CFAR Symposium on Statistics and Data Science in HIV, Providence

  • Bryan Shepherd, "The Vanderbilt-Nigeria Biostatistics Training Program" - invited speaker

On Tuesday, Kaidi Kang was named a NESS Student Research Award winner. He notes that the work started as as a course project with Dr. Liu. He will also be presenting work later this summer on effect sizes in brain-wide association studies (BWAS) at the Joint Statistical Meetings (#JSM2023) and the Organization for Human Brain Mapping's annual meeting (#OHBM2023), which was conducted in collaboration with professor Jonathan Schildcrout, assistant professor Ran Tao, PhD student Jiangmei Ruby Xiong, MS student Megan Taylor Jones, and assistant professor Simon Vandekar

Kaidi Kang with poster during Vanderbilt's Alzheimer's Disease Research Day. He was the winner of Best Data Blitz at the 2023 event.

Chris Slaughter wins 2023 Vanderbilt Epidemiology Teaching Award

Associate professor Chris Slaughter has received the 2023 Vanderbilt Epidemiology Teaching Award. The student-nominated award honors a faculty member for their exceptional effort in training the next generation of epidemiologists in the PhD program.

Students who nominated Chris said that he “really tied all of the concepts we learned in our previous classes together to make them easier to understand,” and that he is “very patient and takes the time to explain concepts and ensure that they are understood.”

Chris received his PhD in biostatistics from the University of North Carolina at Chapel Hill. Since joining the Vanderbilt School of Medicine as an assistant professor in 2007, he has taught Clinical Pharmacology Biostatistics, Statistics for Biomedical Research, Modern Regression Analysis (for which he was a founding instructor), and Design and Analysis of Time to Event Data. He has co-authored almost 200 peer reviewed papers.

Some of Chris’s current research projects include a structure based design of trimer interface epitope focused universal influenza vaccines and therapeutic human monoclonal antibody treatments for filoviruses.

He is also part of the department’s upcoming Coursera program, which will debut within the next year. The program will include a series of courses on applied statistics in biomedical science. Chris is teaching Data Science Workflow for Clinical Trial Data, which will provide students with hands-on experience for successfully working with data collected during a randomized clinical trial.

Other courses in the program will be led by professor Tatsuki Koyama, assistant professor Andrew Spieker, and department chair Yu Shyr.

Congratulations, Chris, and thank you for all your hard work!