Every engineering team knows they have a codebase understanding problem. Few have quantified it. Here's the math.
Direct Costs
Regressions from Incomplete Understanding
Average production incident cost: $5,000-$50,000 (depending on severity and duration). Root cause for 60% of incidents: a developer changed code without understanding its full impact.
For a team averaging 2 understanding-related incidents per month: $120K-$1.2M per year.
Slow Onboarding
New developer at $180K salary, operating at 50% capacity for 6 months: $45K in lost productivity per hire. For a team hiring 8 engineers per year: