An Elegant Puzzle: Systems of Engineering Management

by Will Larson

That’s less than four hours per engineer per month if you can leverage your entire existing team, but training comes up again here: if it takes you six months to get the average engineer onto your interview loop, each trained engineer is now doing three to four hours of hiring-related work per week, and your trained engineers are down to approximately 0.4 efficiency. The overall team is getting 1.06 engineers’ worth of work out of every three engineers. It’s not just training and hiring, though: For every additional order of magnitude of engineers, you need to design and maintain a new layer of management. For every ~10 engineers, you need an additional team, which requires more coordination.14 Each engineer means more commits and deployments per day, creating load on your development tools. Most outages are caused by deployments, so more deployments drive more outages, which in turn require incident management, mitigations, and postmortems. Having more engineers leads to more specialized teams and systems, which require increasingly small on-call rotations so that your on-call engineers have enough system context to debug and resolve production issues. Consequently, relative time invested in on-call goes up.