Panagiotis Vagenas studied substance misuse and its effect on HIV transmission while he was a staff scientist at Yale School of Medicine in New Haven, Connecticut. Now he works for the non-profit Project Concern International (PCI) in San Diego, California, where he helps scientists in the field to design and carry out their projects.

How did you start out on this track?

What's always motivated me is trying to help people. So, in 2010, I did a master's in public health after a postdoc in basic HIV research at Rockefeller University in New York City, and eventually joined Yale.

Why did you leave Yale?

I didn't get a grant I applied for, and thought it was time to move on.

What do you do now?

I advise field teams at PCI on how to answer a research question — from forming a hypothesis and helping to write the research protocol to going through the ethics approval process. I make sure that everyone follows the same standard of high-quality, rigorous research as in academia.

Why do you like the job?

I can clearly see the impact of my work. Last summer, I went to Guatemala, and met some people involved in PCI's micro-financing programme for women. Many told me that the programme had helped them to find a social network and become financially empowered. That experience made it all worth it.

Do you have any regrets?

I made the right choice in leaving Yale. Three months after starting this job, I found out I'd got my grant after all. It was a bittersweet moment — but I withdrew my application.

What advice would you give anyone hoping to change careers?

I had to soul search to work out what I wanted to do. I was extremely proud to be a faculty member at Yale, but you need to think about who you want to be and make a bold move when you feel that it is right.

This interview has been edited for length and clarity. See go.nature.com/2k2nh2n for more.