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Terms and Definitions
AHRQ ICD-10-CM CCSR Diagnosis Groupings
For discharges or visits on or after October 1, 2015, the Agency
for Healthcare, Research, and Quality’s (AHRQ) Clinical
Classification Software Refined (CCSR) uses the primary ICD-10-CM diagnosis
code to assign a CCSR diagnosis category for inpatient discharges
and emergency department visits. Please visit the link below
for more information.
AHRQ ICD-10 CCSR Diagnosis Categories
AHRQ CCS Services and Procedures Groupings for CPT/HCPCS
For outpatient surgery visits occurring on or after October 1, 2015,
the highest charge Current Procedural Technology (CPT) code or
Healthcare Common Procedure Coding System (HCPCS) code is used
to assign the CCS Services and Procedures category. Please visit
the link below for more information.
AHRQ CCS Services and Procedures Categories for CPT/HCPCS
Average Length of Stay
This is the total number of days spent in the
hospital by a given set of patients, divided by the
number of discharges. The average length of stay affects
charges because longer stays generate higher charges. In
addition, the average length of stay is a rough indicator
of hospital efficiency or program philosophy. For
example, two hospitals may have significantly different
averages for psychiatric inpatient treatment. These
differences may indicate a facility's choice between
extended hospital stays, which tend to have higher
charges, and alternatives such as outpatient treatment,
which tend to have lower charges.
Average (Mean) Charge
This is the sum of all charges for a set of
hospitalizations, divided by the number of discharges.
For example, to determine the average charge for
pneumonia cases, the charges for all pneumonia
cases are added together and divided by the number of
pneumonia cases. The average charge gives an
approximation of what a typical patient would be
Defined as one patient visit, even though more than
one procedure may be performed during the same surgical
episode. For instance, if a myringotomy is performed on
both ears during one visit, only one case will be
counted even though two procedures are performed.
The amount a facility bills for a patient's care is
known as the charge. This may differ substantially from
the amount that the facility collects for its services,
as health care facilities frequently negotiate discounts
with insurance companies or other large purchasers of
health care services.
The term discharge is roughly synonymous with
hospitalization. A patient becomes a discharge once he or
she officially leaves the health care facility. The
number of discharges from a hospital affects how a
hospital is staffed, what types of services a hospital
offers, and how well it competes in the broader health
care system. To some degree it also affects costs
because, when viewed relative to the facility's capacity,
the number of discharges is a partial indicator of
efficiency. The number of discharges is used to calculate
the average charge and the average length of stay at a
Each record submitted to the RFA contains information
about the expected payer for the hospitalization. A
facility compiles information about expected payers from
the bills it generates. Each bill indicates whom the
facility expects to pay for the services; however, the
bills are not always paid by the expected payer.
Insurance may not cover a procedure. A person may not
actually be covered by the indicated insurer. Therefore,
the expected payer is to be viewed as a preliminary
determination of who's footing the bill.
Median Charge and Median Length of Stay
Charges and lengths of stay may also be presented as
medians. The median represents the middle value of a
distribution; half the values lie at or above the median,
and half lie at or below it. If the median charge for
pneumonia patients was $6,500, then half the patients
were charged $6,500 or more and half were charged $6,500
or less. Averages (means) can be significantly affected
by a few unusually low or high values (outliers).
Medians, on the other hand, are not affected to such a
degree by outliers. The median, which is also called the
50th percentile, may be more representative of the
typical charge or length of stay than the mean.
The primary disease or condition for which the
patient was hospitalized or treated, as indicated in the
patient's discharge record. In the RFA's data products, all
diagnoses prior to October 1, 2015 are coded according to the
ICD-9-CM scheme. Beginning with October 1, 2015 and forward,
the RFA's data products use the ICD-10-CM scheme to code diagnoses.
Although a facility may report up to fifteen diagnosis
codes (and an additional external cause of morbidity code when appropriate)
on each patient record submitted to the RFA, the on-line data system
currently contains only the principal diagnosis codes.
A patient may undergo more than one procedure during an
outpatient surgical operation. These procedures are in
no particular order when they are sent to the RFA as part
of the billing data. The RFA ranks the outpatient procedures
by the highest charge and then uses this procedure for