Dr. Caroline Johnston and her advisor, Phebe Vayanos, at Dr. Johnston’s Ph.D. thesis defense
Meet Caroline Johnston, a Fall 2024 Ph.D. graduate whose work has combined optimization, artificial intelligence, and public policy to address pressing societal challenges. From advancing tools to allocate housing resources for those experiencing homelessness to navigating her academic journey during the COVID-19 pandemic, Caroline’s experience at USC and CAIS has been marked by resilience, innovation, and interdisciplinary collaboration. As she prepares for her next chapter at the RAND Corporation, Caroline reflects on the highlights of her Ph.D. journey, the impact of CAIS on her research, and her advice for future scholars eager to explore the intersection of AI and social good. Join us in learning more about Caroline’s journey!
Tell us a little about yourself.
My research focuses on advancing optimization methodology and theory to aid human and AI decision-making in real public policy problems. I have advanced and developed preference elicitation tools for public policy using optimization, focusing on applications in public health such as the COVID-19 pandemic and homelessness.
On a personal note, I enjoy playing recreational volleyball and video games, doing puzzles, and reading books.
What factors influenced your decision to pursue your Ph.D. at USC?
After completing my undergraduate degree, I wanted to continue to study optimization and operations research. Ideally, I would create new knowledge in this field and apply this to problems of social good or great societal importance. After looking into various programs, I knew that by joining the lab of my advisor, Phebe Vayanos, I would be able to do just this. Plus, I had previously spent time in the greater Los Angeles area as part of summer internships. I felt that I had a support network in the area and could see myself living there for the next 5 or so years!
What were some of your highlights at USC?
A professor once told me that in academia, the wins are so few and far between, so it’s important to celebrate them when they actually happen! This included “large wins” such as having a paper accepted, receiving a fellowship, or being able to celebrate my graduation with my family who flew in to Los Angeles to do so. “Small wins” were important too, such as getting code to finally stop crashing or having a mathematical proof come together. I have also met very interesting friends and labmates who I am grateful for their support on this journey.
On a more personal note, something unexpected that I really enjoyed at USC was taking advantage of its fantastic cinema opportunities. This included getting to watch movies before they were released in theatres and having access to interesting Q&A sessions with various cast and crew members.
Tell us about why you decided to get involved in CAIS.
I wanted to work on projects that had the potential for real, positive impact on society. CAIS provided a great opportunity to pursue this in an interdisciplinary setting where I was able to collaborate and learn from experts in various fields.
What specific projects or initiatives within CAIS have you been involved in, and how have they impacted your understanding of the intersection between social work and artificial intelligence?
I have recently worked on a collaborative project with the social work researchers of CAIS. In this project, we interviewed policymakers in homeless services about their perceptions and openness to using AI tools to allocate scarce housing resources to individuals experiencing homelessness. It has been a great experience to see how the fields of AI and social work can work together with their respective expertise to approach these problems. Everyone on the social work side has helped to cover my “blind spots” from my engineering-based training and for that I am really grateful.
How did the interdisciplinary environment at CAIS shape your approach to research and problem-solving?
My collaborators from different fields and backgrounds really challenged me to think about problems and their solutions from varied perspectives. Even though a PhD is about becoming an expert in a very specialized area, I have had exposure to a lot of different methodologies. This will only help me in the future, as not every problem will be “a nail.”
If you could describe your Ph.D. experience at USC and CAIS in three words, what would they be and why?
Marked by COVID-19
Of course, pursuing a PhD is hard, but I think it was hard in ways I never expected or could have imagined. The COVID-19 pandemic hit about 6 months into the first year of my PhD. I ended up moving in with my parents in the Boston area for 1.5 years during the lockdown, which made for weird moments such as taking my PhD screening exam in my childhood bedroom and lots of other isolating experiences that we all collectively went through as a society. Even when coming back in person to campus, it took a long time to reach a sense of “normalcy” both for personal and institutional reasons. It was really hard to rebuild a sense of community after this, both in terms of research and social connections. For as much as the pandemic opened up new pathways such as flexibility through remote work, I can’t help but think that a lot of my PhD journey was stunted from the lingering effects of the pandemic. It makes me hopeful that PhD students starting now will take full advantage of the opportunities presented to them as they begin their journey without such effects!
Tell us about your plans for the future.
Immediately, I look forward to becoming a couch potato as I take a bit of time off after graduation. Then, I’ll be joining the RAND Corporation in Santa Monica, CA as an Associate Operations Researcher. I’m really excited to continue to make an impact on policy problems and to stay local to the Los Angeles area.
Given your experience, what advice would you give to current and future Ph.D. students interested in exploring interdisciplinary research and collaboration, especially within fields like social work and AI?
Talk to people outside of your field and ask them what they’re working on. Go to the social events and talk to someone you don’t already know. Take a class in a different field. Building connections takes time but it will be worth it.
