Get to know the members of ORSSA: Hannah Callaghan

In this edition of Get to Know the Members of ORSSA, we feature Hannah Callaghan, who serves on the Executive Committee as Head of Communications.

In this short interview, we step into Hannah’s world to learn more about her journey in Operations Research, her interests beyond the numbers, and what she enjoys most about being part of the ORSSA community.

Hannah, what is your academic and professional background?

"I studied a BSc majoring in both Applied Mathematics and Operations Research, and have since completed by Honours and Masters in Operations Research. I am now working as a lecturer at Stellenbosch Univeristy."

How (and when) did you first get involved with ORSSA?

"I got involved in ORSSA during my Honours year in 2023. The department was really encouraging students to attend the ORSSA conference to get practise at presenting research as well as to gain exposure to other people working in OR, so I went to the conference and really loved the community. My Masters supervisor (and the current ORSSA president) later encouraged me to nominate myself for a position on the Executive Committee, which is how I became more actively involved."

What position do you hold on Exec and for how long have you had this position?

"I currently the head of communications at ORSSA and have had this position since 2025."

Tell us a bit more about what your role includes on the Exec.

"My role mostly includes managing the blog posts (yup, I am the one managing the ORSSA blog), which includes the tasks of coming up with ideas for content, reaching out to members to write posts about recent conferences or OR-related events, and editing submissions for publishing. My role also includes writing the annual newletter, which is a summary of all that has happened in ORSSA over the past year, you can look at past editions here."

Have you had any other positions on the Exec of ORSSA (and if so, when)?

"Nope, this is the only position I have held."

What do you feel is the biggest benefit of being a member of ORSSA?

"As many previous interviewees in this series have also mentioned, the network you gain is one of the most valuable aspects of being part of ORSSA. It connects you to a community of people working in diverse areas of OR, both academically and professionally, and creates opportunities for collaboration, learning, and support."

What excites you about the field of OR?

"What excites me most about OR is how diverse it is. One day you might be thinking about healthcare systems, the next about delivery routes or education problems. I love that OR gives you the ability to work across so many different types of real-world problems using the same core set of ideas and tools. This can be seen in my limited time in OR, I have worked on projects ranging from vehicle routing, childhood obesity and even F1 race strategy. Everyday has the possibility of something new and diverse."

Was there a specific project or moment that made you realise, "This is why I love OR"?

"During my Honours year, I had the privilege of working on a project for mobile clinics that service farming communities in the Witzenberg region of the Western Cape. The aim of the project was to develop new routes and schedules for the three mobile clinics to ensure that patients were served fairly, while also considering the workload of staff.

Being able to apply OR to a real, tangible problem, and then seeing how the results could make a meaningful difference for both staff and patients, was a true "this is why I love OR” moment, where I could so clearly see the real, tangible impact that OR can have"

What OR technique do you find yourself using the most and why?

"I really enjoy using causal loop diagrams. I find them incredibly useful for visualising complex systems as interconnected and dynamic rather than isolated components. They help to illustrate how different elements influence one another, identify feedback loops, and highlight which variables can drive meaningful change. For me, they are a powerful way of understanding the structure of a system before diving into formal modelling."

What skills do you think OR students should focus on developing today?

"I think OR students often want to jump straight into solving a problem and applying the “math,” which, don’t get me wrong, is the exciting part. However, we sometimes skip over a crucial soft skill in OR: taking the time to clearly understand and structure the problem properly.

In my view, one of the most important skills to develop is problem structuring, being able to interpret a real-world situation, ask the right questions, and translate it into a well-defined OR problem, before reaching for a solution. This makes sure that we really know what we are trying to solve and do end up solving the actual problem."

What has been your favourite ORSSA memory over the years?

"The ORSSA conferences have always been a highlight for me. OR often feels like quite a small field, when I talk to friends or family, very few people know what it is. That’s exactly what makes the conference experience so special. For a few days, you can talk about your work without someone frowning at you when you mention that you work in OR.

Being in that space is incredibly refreshing, suddenly you’re surrounded by people who understand the language of OR, who are grappling with similar types of problems, and who genuinely appreciate the challenges and ideas being shared.

For me, it is always energising and inspiring to be in a room full of like-minded people who are just as passionate about the field."

What piece of advice would you give to students or those new to OR?

"Very easily we can start to feel isolated in the problems that we are trying to solve. But we in fact are part of a whole community of Operations Researchers who share a lot. And a wonderful way to connect with them and feel apart of this community is to go to the ORSSA conference. It's a great way to be connected, to be refreshed and reignited for OR."