An experienced caretaker can hear that a machine is running unusually, while a new colleague sees no warning on the checklist. Years of attention have produced distinctions that are difficult to explain before a relevant situation occurs.

Tacit knowledge includes this practical judgment: recognizing patterns, interpreting exceptions, and knowing which details matter. An organization can have extensive documentation while remaining dependent on people who supply that understanding.

The document and the practitioner do different work

Writing down procedures can preserve steps and reduce avoidable mistakes. It may not preserve the ability to know when the usual procedure is inappropriate. Replacing experienced people with a manual can therefore leave the organization less capable even when every formal instruction survives.

Continuity often requires people to work together long enough for judgment to become discussable through examples. A successor needs opportunities to try, receive feedback, and encounter unusual cases—not merely access to the predecessor’s files.

The danger is most visible during turnover, but the dependence already exists beforehand. Mapping who can interpret problems, and whether others are developing comparable understanding, reveals a different picture from counting how many tasks have written instructions.

Real cases