When a company loses an engineer three months in, the post-mortem usually focuses on salary burned — three months of comp, wasted. But that's the smallest number in the equation.
The Full Cost Stack
A bad engineering hire generates costs across five categories most companies never add up:
1. Direct Compensation Waste
Salary, benefits, equity cliff (if any vested), severance. For a $150K engineer terminated at 90 days, this is roughly $50K all-in. Painful, but visible — and the only number most post-mortems include.
2. Recruiting and Onboarding Cost
Agency fees run 15–25% of first-year comp. Add internal recruiter time, interview cycles across 4–6 engineers, offer negotiation, background checks, equipment provisioning, access setup, and onboarding documentation. That's another $20–40K for a mid-level role.
3. Lost Velocity
This is the hidden multiplier. A bad hire doesn't just fail to contribute — they consume senior engineer time. Code reviews of low-quality PRs, architecture debates that go nowhere, re-explaining context that doesn't stick. Estimate 15–20% of one senior engineer's capacity lost for the duration of the bad hire's tenure.
4. Codebase Cleanup
If the engineer shipped code — and most do, even bad ones — that code has to be reviewed, refactored, or removed. For a 90-day tenure, assume 30–60 hours of cleanup across 1–2 senior engineers.
5. Team Morale and Attrition Risk
This is the one nobody models. Engineers notice when a bad hire isn't managed out quickly. It signals leadership tolerance for underperformance, which degrades culture and increases voluntary attrition risk on your best people. One bad hire leading to one quiet resignation is a 10x cost multiplier.
The Real Number
Add it up for a mid-level engineer at a 50-person company: $50K compensation + $30K recruiting + $25K velocity loss + $10K cleanup + attrition risk. You're at $115K–$130K before anyone quits in frustration.
The industry benchmark of "3x salary" for a bad hire is actually conservative for engineering roles specifically, because the velocity and codebase costs are higher than in most other functions.
What This Means for Hiring Strategy
The ROI on rigorous vetting is asymmetric. An extra week in the interview process — structured take-homes, multiple technical screens, reference calls — costs maybe $5K in recruiter and engineering time. It prevents a $130K mistake. The math is not close.
For staff augmentation specifically, this is why HarborTechAI runs a multi-stage vetting process before any engineer hits a client engagement. The cost of a poor placement — to the client relationship, to the engineer's confidence, to our reputation — dwarfs the cost of the extra screen.