Bus Factor One
Noun · Hacker Culture
Definitions
The most dangerous state for any project: a bus factor of exactly one person. If that person leaves, gets sick, or is hit by the proverbial bus, critical knowledge vanishes. The solution is documentation and knowledge sharing. The reality is hoping Dave never quits.
In plain English: When only one person on the team knows how something critical works — if they leave or get sick, nobody else can keep it running.
A specific anti-pattern in organizational design where critical knowledge concentrates in one person, often because they built the system originally and never documented it. The person becomes simultaneously invaluable and a single point of failure.
Example: 'Maria is our bus-factor-one for the ETL pipeline. We need to get her to document it before her sabbatical, or we're flying blind for three months.'
Source: anti-pattern