Patients have edregtime in hosp, but no intime in the ED dataset.

[belatub]

Many patients have an edregtime/edouttime in their hosp dataset. However, there are not entries for them in the ED dataset. See the following example, where hospital and ED data were joined based on hadm_id:

Is there any explanation for that? Specificially, were these patients in the ED, or not?

[alistairewj]

More than likely these patients are admitted before data collection for MIMIC-IV-ED starts. MIMIC-IV-ED does not include patients admitted between 2008 - 2010. You can check by joining to the patients table and verifying against anchor_year_group.