Assessment reference date means the specific calendar day in the patient assessment process that sets the designated endpoint of the common patient observation period, with most patient assessment items usually referring back in time from this endpoint.

CMS stands for the Centers for Medicare & Medicaid Services.

Comorbidity means a specific patient condition that is secondary to the patient's principal diagnosis that is the primary reason for the inpatient rehabilitation stay.

Discharge. A Medicare patient in an inpatient rehabilitation facility is considered discharged when -

Encode means entering data items into the fields of the computerized patient assessment software program.

Functional-related groups refers to the distinct groups under which inpatients are classified using proxy measurements of inpatient rehabilitation relative resource usage.

Interrupted stay means a stay at an inpatient rehabilitation facility during which a Medicare inpatient is discharged from the inpatient rehabilitation facility and returns to the same inpatient rehabilitation facility within 3 consecutive calendar days. The duration of the interruption of the stay of 3 consecutive calendar days begins with the day of discharge from the inpatient rehabilitation facility and ends on midnight of the third day.

Outlier payment means an additional payment beyond the standard Federal prospective payment for cases with unusually high costs.

Patient assessment instrument refers to a document that contains clinical, demographic, and other information on a patient.

Rural area means: For cost-reporting periods beginning on or after January 1, 2002, with respect to discharges occurring during the period covered by such cost reports but before October 1, 2005, an area as defined in § 412.62(f)(1)(iii). For discharges occurring on or after October 1, 2005, rural area means an area as defined in § 412.64(b)(1)(ii)(C).

Transfer means the release of a Medicare inpatient from an inpatient rehabilitation facility to another inpatient rehabilitation facility, a short-term, acute-care prospective payment hospital, a long-term care hospital as described in § 412.23(e), or a nursing home that qualifies to receive Medicare or Medicaid payments.

Urban area means: For cost-reporting periods beginning on or after January 1, 2002, with respect to discharges occurring during the period covered by such cost reports but before October 1, 2005, an area as defined in § 412.62(f)(1)(ii). For discharges occurring on or after October 1, 2005, urban area means an area as defined in §§ 412.64(b)(1)(ii)(A) and 412.64(b)(1)(ii)(B).