The single most expensive hiring mistake I've made wasn't a skill mismatch. It was a character mismatch.
The person was technically excellent. The work was good. The references were strong. But within six months they'd undermined two other team members, taken credit for shared work, and left a wake of distrust that took a year to repair.
The pattern
Looking back, the warning signs were there in the interview process. Slight evasiveness on questions about past failures. A tendency to subtly diminish previous colleagues. Stories where they were always the hero, never the supporting cast.
I noticed those things at the time. I rationalised them away because the skill fit was so strong. That was the mistake.
What I do differently now
For senior hires, I weight character signals above capability signals when they conflict. Specifically:
- How do they talk about previous teams? Generous, specific praise = good. Vague, dismissive references = warning.
- What's a real failure they own? If they can't produce one without it being humblebrag dressed as failure, they're not self-aware.
- Back-channel references — not the ones they give you. The references on the CV are curated. Find people who worked alongside or under them, not just above.
- How do they handle disagreement in interview? Push back gently on something they said. Watch how they respond. Defensive? Curious? Dismissive?
Why this matters more at small scale
At a 100-person company, a difficult senior hire damages a team. At a 10-person company, they damage the company. At a 5-person company, they can end it.
The smaller the team, the higher the cost of a character mismatch. Build the trust filter first; the skill filter is secondary.