The interview is intended to predict on-the-job performance. An L6 (staff) engineer is expected to lead a team of 6+ engineers in technical direction, and to represent the team in XFN collaboration. An L5 is expected to independently lead and own a project.
So in terms of interview performance, a staff-level performance should indicate some technical leadership and foresight when it comes to direction. The main ways these will be evaluated are through system design and behavior rounds.
- In the system design round, a senior engineer can have a nuanced discussion about tradeoffs, while a staff engineer would go further to talk about what may break in the future and how to guard against that.
- In the behavior round, the main requirement I look for in a staff engineer is that they have influenced the roadmap for a team, and I’m looking for how they did that. How are they able to convince leadership and junior engineers, technical and non-technical parties, about the importance of their plan?
