Central Distributor SID: Description of Data Elements

MDNUM1_S - Physician 1 number (synthetic)

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HCUP encrypted physician identifiers are referred to by different names in the HCUP data across years.

Year	Variable
1988-2000	MDID_S
2001-2002	MDNUM1_S
Beginning with 2003	MDNUM1_R

MDNUM1_S contains a fixed-key (one-to-one) encryption of the supplied physician 1 number (MDNUM1), according to the following rules:

All alphanumeric digits are used in the encryption.
All symbols such as ".,:;'*@" are retained in the encrypted value, but not in the same location.
Leading zeros are encrypted so that the two original physician identifiers "000A6" and "A6" are distinctly different.
When the original physician 1 number and physician 2 number identifiers are the same, the synthetic identifiers, MDNUM1_S and MDNUM2_S, are the same.
When the MDNUM1 in the ambulatory surgery data and the inpatient data are the same, the synthetic identifier, MDNUM1_S is the same.

Except in those data sources where physician license numbers are supplied, it is not known whether the physician identifier MDNUM1_S refers to individual physicians or to groups. If the physician 1 numbers supplied by the data source are not restricted to license numbers, the state-specific note includes available information about reporting practices, including whether MDNUM1_S refers to individual physicians or to groups.

Beginning in the 1993 data, supplied physician 1 identifiers were checked for null characters. If null characters were found, they were replaced by blanks before the identifier was encrypted. Since this conversion was not done in prior years of HCUP data, the encrypted physician 1 identifiers from 1993 on may not match those in earlier years. However, null characters are rarely included.

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Uniform Values

Variable	Description	Value	Value Description
MDNUM1_S	Physician 1 number (synthetic)	16(a)	Synthetic physician identifier
MDNUM1_S	Physician 1 number (synthetic)	Blank	Missing

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State Specific Notes

Arizona

In Arizona two types of physician identifiers are available:

Attending physician is provided in MDNUM1_S and
Physician that performed the primary procedure is provided in MDNUM2_S.

Physician identification numbers may not accurately track physicians across hospitals for the following reasons:

Some hospitals assign their own internal physician identification numbers rather than using the license numbers issued by the licensing agency of the physician or other health care practitioner. Information was not available about the prevalence of this practice.
Some hospitals use one physician identification number for several physicians that are part of the same physician practice group. Information was not available about the prevalence of this practice.
Physician identifiers in July-December 2002 generally include a first-digit prefix of "1"; in other periods, the prefix is generally "0".

The physician identification number includes license numbers from the following board of examiners: Medical, Osteopathic, Podiatrists, and Nurses. In addition, Arizona accepts licensing numbers from other health practitioner licensing boards, but these boards are unspecified. The provided physician identifiers are encrypted during HCUP processing.

The physician identifiers provided by Arizona for the second half of 2002 were constructed differently than the first half of 2002 and following years (i.e., 2003 forward). Physicians cannot be accurately tracked across the second half of 2002.

Colorado

In Colorado two types of physician identifiers are available:

Attending physician is provided in MDNUM1_S and
Physician that performed the principal procedure is provided in MDNUM2_S.

Physician identification numbers may not accurately track physicians across hospitals. The state encourages hospitals to use the Professional State License Number as an identifier, but some hospitals continue to use their own internal identification number. Also, some hospitals appear to pad the Professional State License Number (a 5-digit code). Information was not available from the data source about the prevalence of these practices.

Some hospitals may use one license number for all physicians in order to protect physician confidentiality. Information was not available from the data source about the prevalence of this practice. The provided physician identifiers are encrypted during HCUP processing.

Florida

In Florida two types of physician identifiers are available:

Attending physician is provided in MDNUM1_S and
Operating physician is provided in MDNUM2_S.

Physician identification numbers may be used to track physicians within and across hospitals. Florida reports state license numbers for the physician identifiers. During HCUP processing, physician identifiers were encrypted.

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Central Distributor SID: Description of Data Elements