Joseph Rollinson

About Me

What Drives Me

Three things keep me coming back to work every day:

  1. Mission - I am at my best when I can see the positive impact of my work.
  2. People - I love working with motivated, passionate, and kind people.
  3. Problems - I enjoy solving complex, ambiguous problems both technical and not.

Current Work

Company: Duolingo

Title: Director of Engineering

Role: Engineering Lead for Learning Scaling Area

Learning Scaling is a group of cross-functional teams responsible for ensuring that Duolingo’s learners have access to high quality content no matter what language they are learning or their proficiency. We creatively use new technology (e.g. large language models) and state-of-the-art infrastructure to scale content creation sub-linearly.

I collaborate closely with the area’s other two leads (Learning & Curriculum and Content Program Management) to drive the area’s strategy, roadmap, and execution. I also manage the area’s engineering org. through a group of engineering managers.

Past Work @ Duolingo

Learning Infrastructure Team Lead

Title: Staff Software Engineer

Learning Infrastructure was the first infrastructure team in a product area at Duolingo. We were responsible for addressing the area’s technical debt and redesigning our content serving architecture. This “infrastructure team” model was replicated across Duolingo due to its success.

I spun up and grew the team from 3 to 7 engineers over 2 years. I managed all team members and successfully coached one engineer to replace me as team lead as I moved into area leadership.

Learning Assessment Team Lead

Title: Senior Software Engineer

Learning Assessment was my first foray into team leadership and management. This team was responsible for measuring the efficacy of Duolingo’s teaching methodology for both internal and external purposes. We ran complex studies, built internal assessment tools, and shared our findings with the world. One of our journal articles was the most viewed article in Foreign Language Annals.

The team started as just me and an assessment researcher, meaning that I had to work on everything from performing high-stakes data analysis to building automated pipelines for running studies, to designing novel methods of evaluating Duolingo’s efficacy. I loved it! Over time, we grew to five members across 3 functions.

Check out my publications and Duolingo’s efficacy page for more information.

Individual Contributor

Title: Software Engineer I -> Software Engineer II -> Senior Software Engineer

I started at Duolingo as a backend engineer. Throughout my time as an IC, I focused on our learning systems, especial learner progress and lesson generation.

Education

Carnegie Mellon University - Undergrad

Degree: Double Major in Computer Science and Philosophy

GPA: 3.94

Honors: ACS Scholar

I started at CMU as an undeclared science major, but quickly found out I wasn’t quite as good at Physics and Chemistry as I thought. I found my home in the computer science and philosophy departments. In my first “intro to programming” class, 15-112, my Arduino harp project was voted best in class, and that was it.

I also found a love for academic research. I completed a CS senior thesis and published my first conference paper in Educational Data Mining, which has been cited 50 times.