A listing published when no hire is planned. Reasons vary: building a candidate pipeline, signalling growth, satisfying an internal rule that a role be advertised before an internal candidate takes it, or simply never taking the listing down.
The most-cited estimate is up to 21% of postings, from Hunter Ng, arXiv:2410.21771 (October 2024), using Glassdoor data and an LLM-BERT classifier. Survey-based estimates run much higher because they ask managers about behaviour rather than classifying listings.
Intent is not observable from outside a company. Anything that claims to detect a ghost job is producing a probability from signals — most usefully, how long the listing has been open.