Willem Collier, PhD
Currently working as an Assistant Professor of Research at the University of Southern California.
I received my Ph.D. from the Department of Population Health Sciences with an emphasis in Biostatistics at the University of Utah in 2022.
A brief autobiography
Prior to joining the PHS PhD program I did an undergraduate degree in mathematics (statistics emphasis) and an honors degree in economics. While a PhD student, I worked with clinicians at the University of Utah and at other institutions on a wide range of applied topics and this work shaped my interests in biostatistics and more generally medicine. I worked on methods for surrogate endpoint evaluation with the Chronic Kidney Disease Epidemiology Collaboration for my dissertation work, where my committee was led by Tom Greene and Ben Haaland. I now work as an assistant professor of research at the University of Southern California and my role is primarily devoted to the clinical trials-oriented work of the Children’s Oncology Group.
Describe your experience in the program
I joined the Biostatistics track in the Ph.D. in Population Health Sciences in only its second ever cohort of students in 2017. The program evolved during my time as a PhD student. What was important about this phase was that the Department was incredibly welcoming of student feedback. Members of the Department within and beyond the Division of Biostatistics were motivated to make improvements that benefited the students based on student perspectives all throughout my time in the program.
There are three separate educational tracks for PhD students within the department and there are a variety of avenues that facilitate working with fellow students across the separate tracks. For example, some amount of required and optional coursework is designed for students of all three tracks. The educational program itself is thus very conducive learning that develops multidisciplinary researchers. As a student, I was very grateful to have learning opportunities alongside students with diverse interests as it helped me place myself as a biostatistician within a broader research community, which helped shape my interests and prepared me to think critically about the work I wanted to do both during my dissertation phase and after graduating.
When I started the program, I was immediately paired through a specific funding avenue with a surgeon at Utah in the Division of Plastic Surgery. My training in biostatistics was thus shaped from the very beginning by collaboration with clinicians. I learned how to understand the scientific interests of my clinical collaborators and how to pair specific research questions with analytical methods. This helped me develop important collaborative skills in communicating about science and statistics, finding solutions or compromises when there were different ideas about research strategies, and in figuring out what in research is practical.
I felt that I had no shortage of opportunities for dissertation topics. I ultimately discovered my dissertation area of focus through a special topics class taught by my thesis chair (Tom Greene), but I had many other options for dissertation related work. This is partially because of the many areas of expertise among the biostatistics faculty in PHS, but also because our faculty is well integrated into the broader School of Medicine research community (and beyond). PHS faculty have access to data and collaborators addressing many scientific questions that require broad innovation in statistical methods.
What was your favorite class?
My favorite classes were the causal inference classes taught by a variety of faculty in our department, but led by Tom Greene (during my time as a student). These classes were pivotal in shaping my understanding of how to define research questions and how to address those questions through the design and analysis of a study to strengthen the intended interpretation of the results to be meaningful to decision makers (clinicians, policymakers, etc).
Describe some of your research experiences
I worked with a number of Divisions at Utah and beyond on applied research projects. For example, I worked with the Division of Plastic Surgery on a variety of projects evaluating surgical outcomes and how they might be prevented or predicted for purposes of early intervention. We worked on one project assessing variation in postoperative opioid prescribing and use for breast reconstruction patients, and I actually coauthored a paper related to those analyses with my wife (among others), who is now a pediatrician.
For my dissertation phase, I worked with the Chronic Kidney Disease Epidemiology Collaboration on applied and methodological projects related to the evaluation of surrogate endpoints for chronic kidney disease clinical trials. This work has resulted in a number of submitted and accepted papers that will help advance the feasibility of clinical trials in the CKD space. I also had the opportunity to present my work on multiple occasions to members of the National Kidney Foundation and the US FDA. All of these opportunities were only possible because of the encouragement of my participation by my mentors in the PHS program.
What did you enjoy most about the program?
I enjoyed the dissertation phase and working closely with faculty mentors on my dissertation and related projects. I felt that this phase was an opportunity to grow from just being a student into being a collaborator, and my mentors did a lot to support my growth as a statistician and researcher. There were many opportunities to grow such as presenting my work to the National Kidney Foundation, which were admittedly frightening at the time. But being trusted with presenting my work to such audiences and representing our research group gave me the confidence I needed to trust myself as my own researcher. It was also very fun working with such an engaged group - I looked forward to every meeting.
What is your next step and how you feel the program prepared you for this?
I am recently hired an assistant professor of research at the University of Southern California and within that role a faculty statistician for the Children’s Oncology Group. I am taking on a role as a statistician in a very collaborative and fast paced setting. I feel my training in PHS at Utah prepared me with the collaborative skills (communication, writing, presenting, and many others) needed to help move the pediatric cancer clinical trials forward.
What advice you have for future students?
Enjoy the research community and know that whoever you are and whatever your background you have a place in research (and/or in teaching). In fact, the more different your background the better. Exciting new things come about when people who think differently work together, not just when groups of people all with the same training and background work together.
What was your training prior to starting and how long did it take you finish?
I did undergraduate degrees in math and economics (no masters degree). I completed the PHS PhD program in 5-years.
Were you able to participate in collaborative research? If so, how many collaborative publications did you participate in?
I participated in collaborative research throughout the duration of my time in the PHS program and graduated with 10 publications (I had 0 pending at the start).
What was your thesis topic and how did you identify it?
I worked on statistical methods for the evaluation of surrogate endpoints and the specific projects were motivated by challenges to surrogate endpoint evaluations in the chronic kidney disease space. I identified my topic area because my thesis chair, Tom Greene, gave a special topics course on surrogate endpoints during my second year as a PhD student. The specific methods revolve around Bayesian hierarchical meta-regression analyses. I had coursework in a variety of areas that helped prepare me for my thesis work such as Ben Haaland’s multilevel modeling class. I did not have specific training in Bayesian statistics, but my advisors helped me develop reading lists and met regularly with me to work through problems to gain expertise in relevant methods.
Did you talk about the mentorship you received?
My favorite part of the PHS PhD program was the mentorship I received. Among the PHS faculty, I was mentored by Tom Greene, Ben Haaland, and Jonathan Chipman. I felt included and supported in the research efforts of the faculty I worked with, which helped motivate me and build confidence into feeling as if I could contribute as one of their collaborators. I also always looked forward to meeting with my mentors and discussing science with them. I think the faculty in PHS are first and foremost good people and they are there to support students.