```
Medicare: Referrals to Physician-Owned Imaging Facilities Warrant HCFA's
Scrutiny (Letter Report, 10/20/94, GAO/HEHS-95-2).

Because Florida had the only statewide information then available on
doctors with a financial stake in imaging center joint ventures, GAO
analyzed 1990 Medicare claims for imaging services ordered by physicians
in that state.  GAO found that Florida doctors with a financial interest
in such centers ordered about $10 million more in Medicare-paid imaging
services than other doctors in 1990.  Florida physicians with imaging
facilities in their offices, group practices, or other practice settings
also had imaging rates compared with those of other physicians. The
Department of Health and Human Services has not yet finalized the
regulations and procedures needed to implement and enforce federal
self-referral restrictions that would apply to doctors with a financial
interest in joint ventures.  Moreover, the Health Care Financing
Administration has no system to check physician-referral patterns to
identify abusive overutilization of self-referrals.

--------------------------- Indexing Terms -----------------------------

 REPORTNUM:  HEHS-95-2
     TITLE:  Medicare: Referrals to Physician-Owned Imaging Facilities 
             Warrant HCFA's Scrutiny
      DATE:  10/20/94
   SUBJECT:  Health care cost control
             Medical services rates
             Medicare programs
             Disease detection or diagnosis
             Laboratories
             Conflict of interest
             Physicians
             Medical examinations
             Billing procedures
             Medical equipment
IDENTIFIER:  Florida
             Medicaid Program
             
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Cover
================================================================ COVER

Report to the Chairman, Subcommittee on Health, Committee on Ways and
Means, House of Representatives

October 1994

MEDICARE - REFERRALS TO
PHYSICIAN-OWNED IMAGING FACILITIES
WARRANT HCFA'S SCRUTINY

GAO/HEHS-95-2

Medicare:  Physician Referrals

Abbreviations
=============================================================== ABBREV

  CPT - Current Procedural Terminology
  CT - computed tomography
  HCFA - Health Care Financing Administration
  HHS - Department of Health and Human Services
  MRI - magnetic resonance imaging
  OBRA-1993 - Omnibus Budget Reconciliation Act of 1993
  UPIN - unique physician identification number

Letter
=============================================================== LETTER

B-253835

October 20, 1994

The Honorable Fortney H.  (Pete) Stark
Chairman, Subcommittee on Health
Committee on Ways and Means
House of Representatives

Dear Mr.  Chairman: 

Imaging services, such as magnetic resonance imaging (MRI), computed
tomography (CT), ultrasound, and X rays, accounted for over $4.6
billion in Medicare Part B allowed charges in 1992.  These services
are frequently available outside hospitals at joint-venture imaging
centers, group practices, shared-facility arrangements, and other
settings.  Where physicians have a financial interest in the imaging
facility, concerns have been raised about the potential for excessive
use and costs when physicians refer their patients to these
facilities--a practice known as self-referral. 

Because of the concerns associated with self-referral, you asked us
to compare the Medicare imaging referral rates of physicians who
invested in joint-venture imaging centers with the referral rates of
other physicians.  On April 20, 1993, we testified before the
Subcommittee on Health on the preliminary results of our analyses.\1
Subsequent to our testimony, the Congress included new restrictions
on Medicare and Medicaid self-referrals in the Omnibus Budget
Reconciliation Act of 1993 (OBRA-1993).\2 These new restrictions,
which will become effective January 1, 1995, cover 10 types of
medical services, including diagnostic imaging.  OBRA-1993 also
extends Medicare restrictions on clinical laboratory self-referrals,
enacted in 1989, to the Medicaid program.  The Medicare and Medicaid
restrictions generally exempt in-office ancillary services and
referrals within group practices, but OBRA-1993 also authorizes the
Secretary of Health and Human Services to establish any additional
regulations needed to protect against program abuse by physicians
using the exemptions to circumvent the self-referral restrictions. 

Recently, we provided the Subcommittee with analyses of imaging
referrals within physicians' offices, group practices, and similar
settings where the ordering physician and the imaging provider had
the same Medicare physician or billing identification numbers.\3
Imaging in these settings is generally exempt from the OBRA-1993
self-referral restrictions. 

The Congress is now considering legislation that would modify the
OBRA-1993 exemptions for self-referral within group practices and
extend the Medicare and Medicaid self-referral restrictions to all
fee-for-service insurance plans.  To assist the Congress as it
considers this legislation, this report consolidates the final
results of our two studies on physician referrals for imaging
services:  (1) referrals by physicians with a financial interest in
joint-venture imaging centers, and (2) referrals for imaging provided
within the referring physicians' practice settings. 

Our analyses were based on calendar year 1990 Medicare claims for
imaging services ordered by Florida physicians.  We used Florida
claims for our analyses because we also had access to information
identifying Florida physicians with a financial interest in imaging
center joint ventures--the only such statewide information then
available.  That information was gathered in 1990 by researchers at
Florida State University for the Florida Health Care Cost Containment
Board.  Although Florida has a larger Medicare population and more
imaging facilities than some other states, we believe that our
conclusions about the relationship between physician investment in
imaging facilities and their imaging referral rates are generalizable
nationwide because they are based on a large-scale analyses of
physician behavior rather than the characteristics of the patient
population or other demographic variables. 

While we did not formally assess the internal controls used by
Florida Blue Cross and Blue Shield or Florida State University to
ensure the accuracy of their data, we performed extensive tests to
evaluate the accuracy of their data and our analyses, as described in
appendix I.  We performed our work between April 1993 and July 1994,
in accordance with generally accepted government auditing standards. 
Appendix I further describes our scope, data sources, and
methodology, and appendices II and III present detailed information
on imaging referral patterns for each of seven types of imaging
services. 

--------------------
\1 Medicare:  Physicians Who Invest in Imaging Centers Refer More
Patients for More Costly Services (GAO/T-HRD-93-14, Apr.  20, 1993). 

\2 Omnibus Budget Reconciliation Act of 1993, Public Law 103-66,
August 10, 1993. 

\3 Medicare Diagnostic Imaging Rates (GAO/HEHS-94-129R, Apr.  5,
1994). 

   RESULTS IN BRIEF
------------------------------------------------------------ Letter :1

Florida physicians with a financial interest in joint- venture
imaging centers had higher referral rates for almost all types of
imaging services than other Florida physicians.  The differences in
the referral rates were greatest for costly high-technology imaging
services.  For example, physicians with an interest in imaging
centers that offered MRI services ordered twice as many MRI scans as
other physicians.  Medicare costs in Florida would have been about
$10 million less in 1990 if physicians with a financial interest in
joint-venture imaging centers ordered imaging services at the same
rates as other Florida physicians practicing in the same specialties. 

Florida physicians with imaging facilities in their offices, group
practices, or other practice settings also had high imaging rates
compared with those of other physicians.  Relatively few physicians
provided in-practice MRI or CT services in 1990, but physicians with
access to these services within their practices ordered three times
as many MRI scans and twice as many CT scans for their patients as
other physicians.  More significantly, in-practice rates for
ultrasound and echocardiography were 5.1 and 4.8 times higher,
respectively, than rates for physicians who referred patients to
facilities outside their practice settings. 

The Department of Health and Human Services (HHS) has not yet
finalized the regulations or procedures needed to implement and
enforce the OBRA-1993 self-referral restrictions as they apply to
physicians with a financial interest in joint ventures.  Moreover,
the Health Care Financing Administration (HCFA) and the contractors
that administer the Medicare program have not developed procedures to
systematically monitor physician referral patterns in a way that
would allow them to identify abusive overutilization of medical
services through in-practice self-referrals. 

   BACKGROUND
------------------------------------------------------------ Letter :2

As we reported in 1992,\4 high Medicare reimbursement rates supported
a proliferation of diagnostic imaging facilities after Medicare began
covering MRI scans in 1985.  Few states regulated the establishment
of facilities that provided imaging services outside of hospitals--in
physicians' offices, group practices, or joint-venture imaging
centers--and imaging providers were able to realize profits even in
relatively low-volume settings.  These two factors contributed to a
rapid growth in the number of physician-owned imaging facilities. 
For example, in 1990, about 24 percent of Florida physicians
practicing in neurological surgery had a financial interest in an MRI
joint venture facility. 

Since 1990, Medicare payment levels for many imaging services have
declined as HCFA has phased in the congressionally mandated Medicare
Part B fee schedule.  For example, the 1994 Medicare payments for
some MRI and CT procedures are 31 to 32 percent lower than the
payments allowed in 1990.  The lower payment levels more closely
reflect the costs of efficient high-volume providers, but they also
create an incentive for physicians with investments in low-volume
imaging facilities to maintain profitability by ordering more
services. 

The Congress and some state legislatures have enacted restrictions on
some self-referrals.  In 1989 the Congress amended Title XVIII of the
Social Security Act to prohibit the referral of Medicare patients to
clinical laboratories by physicians who have an investment in those
laboratories.  In 1992 and 1993, Florida and several other states
enacted measures to more broadly restrict referrals to other
diagnostic and therapeutic medical facilities by physicians with a
financial interest in those facilities.  Then, in August 1993, the
Congress included provisions in OBRA-1993 that will extend the
Medicare clinical laboratory self-referral ban to Medicare and
Medicaid payments for 10 additional types of medical services,
including diagnostic imaging. 

The OBRA-1993 self-referral restrictions generally do not prohibit
referrals for services that patients obtain within the practice
settings of the referring physician.  These in-practice services,
such as X rays and ultrasound services, can increase physician and
patient convenience and allow the ordering physician to supervise the
services.  However, limited studies by others\5 have raised concerns
that in-practice investment in expensive imaging equipment is
associated with overutilization of imaging services, similar to the
higher imaging rates associated with self-referral to physician-owned
joint ventures. 

Recognizing the potential for using group-practice or shared-facility
arrangements to circumvent the self-referral ban, the 1993 federal
legislation also (1) places some restrictions on in-office ancillary
services; (2) requires billings by a group practice to use the
billing number assigned to the group, thereby facilitating the
identification of services ordered and provided within group
practices; and (3) allows the Secretary of HHS to establish
additional regulations to protect against abusive use of the
exemptions to the self-referral ban.  Also, the ability to track
physician referral patterns has been enhanced by the implementation
of unique physician identification numbers (UPIN) and the
requirement, effective January 1, 1992, that all claims for medical
services include the UPIN of the ordering or referring physician. 

--------------------
\4 Medicare:  Excessive Payments Support the Proliferation of Costly
Technology (GAO/HRD-92-59, May 27, 1992). 

\5 Bruce J.  Hillman, M.D., and others, "Physician Utilization and
Charges for Outpatient Diagnostic Imaging in a Medicare Population,"
The Journal of the American Medical Association (Oct.  21, 1992), pp. 
2050-2054; Stephen E.  Radecki, Ph.D, and James P.  Steele, M.D.,
"Effect of On-site Facilities on Use of Diagnostic Radiology by
Non-radiologists," Investigative Radiology (Feb.  1990), pp. 
190-193. 

   INVESTORS IN JOINT-VENTURE
   IMAGING CENTERS REFER MORE
   PATIENTS FOR MORE COSTLY
   SERVICES
------------------------------------------------------------ Letter :3

Our analyses of the imaging referral patterns of over 16,000 Florida
physicians show that those physicians with a financial interest in
joint-venture imaging centers ordered more imaging tests and more
costly types of imaging services for their Medicare patients than
other physicians practicing in the same specialty. 

Using information from the Florida Health Care Cost Containment Board
and Florida Blue Cross and Blue Shield, we identified 2,395
physicians who had a financial interest in joint-venture imaging
centers and referred Medicare patients for imaging services.  We
classified these physicians as owners and compared their imaging
referral rates (imaging services per thousand office visits) to
13,762 other Florida physicians whom we classified as nonowners.\6 We
made separate comparisons for each of seven types of diagnostic
imaging services--MRI scans, CT scans, nuclear medicine scans,
echocardiography, ultrasound services, complex X rays, and simple X
rays. 

Because some physician specialties, such as neurology and
orthopedics, make greater use of some types of imaging than other
specialties, we analyzed the differences in referral rates by
physician specialty and computed overall owner-to-nonowner referral
ratios that are adjusted for the number of imaging services ordered
by each specialty. 

Overall, owners had higher imaging rates than nonowners for almost
all types of imaging services.  Owners ordered 54 percent more MRI
scans; 27 percent more CT scans; 37 percent more nuclear medicine
scans; 27 percent more echocardiograms; 22 percent more ultrasound
services; and 22 percent more complex X rays.  The referral rates for
simple X rays were about the same for owners and nonowners.  Summary
counts of the physicians, imaging services, and office visits used in
our analyses are provided in appendix II, table II.1.  Detailed
referral rates and owner-to-nonowner ratios by physician specialty
are provided in appendix II, tables II.2 and II.3. 

We further analyzed the differences in owner and nonowner referral
rates for MRI and CT scans, the two most expensive types of imaging
services.  Our analyses show that 952 Florida physicians had a
financial interest in imaging centers that offered MRI services, and
those physicians ordered twice as many MRI scans for their Medicare
patients as nonowners.  As shown in figure 1, among the six
specialties that ranked highest in the number of MRI referrals,
owners in all six specialties had higher MRI referral rates than
nonowners, and owners in general practice ordered three times as many
MRI scans as their nonowner counterparts.  The detailed referral
rates and MRI owner-to-nonowner ratios by physician specialty are
provided in appendix II, table II.4. 

   Figure 1:  MRI Referrals by MRI
   Owners and Nonowners

   (See figure in printed
   edition.)

Note:  These six specialties ranked highest in the number of MRI
referrals, accounting for about 80 percent of the MRI referrals in
our analysis.  See appendix II, table II.4. 

Similarly, our analyses show that 1,369 Florida physicians had a
financial interest in imaging centers that offered CT services. 
Overall, those physicians ordered 29 percent more CT scans for their
Medicare patients than nonowners.  As shown in figure 2, owners in
five of the six specialties that ranked highest in the number of CT
referrals had higher CT referral rates than their nonowner
counterparts.  The detailed referral rates and CT owner-to-nonowner
ratios by physician specialty are provided in appendix II, table
II.5. 

   Figure 2:  CT Referrals by CT
   Owners and Nonowners

   (See figure in printed
   edition.)

Note:  These six specialties ranked highest in the number of CT
referrals, accounting for about 65 percent of the CT referrals in our
analysis.  See appendix II, table II.5. 

These analyses suggest that self-referral to joint-venture imaging
centers is associated with significant overutilization of imaging
services.  We estimate that Medicare costs in Florida would have been
about $10 million less in 1990 if Florida physicians with a financial
interest in joint-venture imaging centers had referred their patients
for imaging services at the same rates as their peers practicing the
same specialties.  Furthermore, the Congressional Budget Office
estimated that the OBRA- 1993 restrictions, which generally apply to
these types of self-referrals, will save Medicare $350 million and
Medicaid $37 million over 4 years. 

--------------------
\6 As discussed in appendix I, our nonowner category includes some
unidentified Florida physicians known to have a financial interest in
imaging center joint ventures. 

   PHYSICIANS WITH IN-PRACTICE
   IMAGING FACILITIES ORDER MORE
   SERVICES THAN PHYSICIANS WHO
   REFER TO OTHER FACILITIES
------------------------------------------------------------ Letter :4

Florida physicians with imaging facilities in their offices, group
practices, or other practice affiliations ordered imaging tests much
more frequently than physicians who referred their patients to
imaging facilities outside their practices. 

Using claims for imaging services and office visits billed to
Medicare in Florida in 1990, we identified physicians who ordered
imaging services and provided those services themselves or through
other physicians within their practice affiliations.  For each type
of imaging service, we classified the ordering physicians as having
in-practice imaging patterns if more than 50 percent of the imaging
services they ordered were provided from within their practice
affiliations.  Similarly, we classified physicians as having referral
imaging patterns if more than 50 percent of the imaging services they
ordered were performed at facilities outside their practice
affiliations. 

Our analyses of these two groups of physicians by practice specialty
showed that physicians with in-practice imaging patterns had much
higher imaging rates than physicians with referral imaging patterns. 
As shown in appendix III, table III.1, the in-practice imaging rates
were about 3 times higher for MRI scans; about 2 times higher for CT
scans; 4.5 to 5.1 times higher for ultrasound, echocardiography, and
diagnostic nuclear medicine imaging; and about 2 times higher for
complex and simple X rays. 

Although in-practice imaging is commonplace for some physician
specialties and some types of imaging services, our analyses showed
that in-practice imaging rates were higher than referral imaging
rates for nearly all specialties and imaging services.  For example,
echocardiography is used extensively by physicians practicing in
cardiovascular disease.  Our analyses showed that 464 cardiovascular
specialists used in-practice echocardiography and 401 referred their
patients to echocardiography facilities outside their practices.  As
illustrated in figure 3, the in-practice echocardiography rates were
2.6 times higher than the referral rates for cardiovascular
specialists.  Furthermore, the in-practice echocardiography rates for
physicians in internal medicine and general practice exceeded not
only the referral rates of their peers in the same specialties, but
also the referral rates of cardiovascular specialists. 

Echocardiography use is of particular importance nationally to the
Medicare program:  in terms of allowed charges in 1993, one type of
echocardiogram\7 ranked higher than any other imaging procedure and
ranked 10th among the top 200 Medicare procedures, accounting for
almost $423 million. 

   Figure 3:  Echocardiography
   Utilization by Physicians With
   In-practice and Referral
   Imaging Patterns

   (See figure in printed
   edition.)

Note:  These three specialties ranked highest in the number of
echocardiograms, accounting for about 82 percent of all the
echocardiography services in our analysis.  See appendix III, table
III.5. 

--------------------
\7 Echocardiography procedure code 93307, complete real time
echocardiography with two dimensional image documentation, with or
without M-mode recording.  Over 3.4 million of these echocardiograms
were paid for by Medicare in 1993. 

   HCFA NEEDS TO MONITOR REFERRAL
   PATTERNS TO ENFORCE
   SELF-REFERRAL RESTRICTIONS AND
   IDENTIFY OVERUTILIZATION
------------------------------------------------------------ Letter :5

Although HHS and HCFA have begun work on the regulations and
reporting requirements needed to implement the OBRA- 1993
self-referral restrictions, HCFA has not implemented a systematic way
to monitor physician referral patterns to identify overutilization
and potentially abusive self-referral practices.  The need to
systematically monitor in-practice referrals and trends is
particularly important because the self-referral restrictions imposed
under OBRA- 1993 may provide an incentive to reorganize
physician-owned joint-venture imaging centers into group practices or
shared-facility arrangements exempt from those restrictions. 

HCFA and the Medicare contractors are currently using focused medical
review to help identify medical procedures where local utilization
rates are higher than national averages and, therefore, warrant
special prepayment reviews.  However, as discussed in our recent
report on HCFA review of claims payments,\8 HCFA and the carriers
have not implemented the type of physician profiling and trend-
analysis reports that would routinely flag questionable referral
practices.  HCFA has required the carriers to develop the capability
to perform profiling by ordering and referring physicians and is
testing the use of this information at a small number of carriers. 

Since Medicare regulations now require the use of UPIN identifiers,
referring physician numbers, and group practice numbers on Medicare
claims, HCFA and the Medicare carriers have the opportunity to more
closely monitor referral patterns and in-practice imaging
utilization, and to investigate potential overutilization linked to
referral arrangements.  High-cost imaging services such as MRI, CT,
diagnostic nuclear medicine, advanced ultrasound services, and
echocardiography warrant particular attention by HCFA. 

--------------------
\8 Medicare:  Inadequate Review of Claims Payments Limits Ability to
Control Spending (GAO/HEHS-94-42, Apr.  28, 1994). 

   CONCLUSIONS
------------------------------------------------------------ Letter :6

Physicians with a financial interest in imaging facilities--whether
through investments in joint-venture imaging centers or through
in-practice imaging--order more imaging services for their patients
than do other physicians.  The recently enacted Medicare and Medicaid
ban on self-referrals for designated medical services offers the
potential for reducing overutilization of imaging, especially imaging
provided by physician-owned joint ventures.  However, physicians who
order and provide these services within their practices may still
have a financial incentive to overutilize the services, especially as
payment levels generally decrease under the Medicare Part B fee
schedule. 

The Congress has provided HHS with the tools needed to identify and
restrict self-referrals and overutilization of in-practice imaging
services within the Medicare and Medicaid programs.  These tools
include mandatory reporting of physician investment in medical
facilities that provide designated health services, mandatory use of
referring physician identification numbers, and the flexibility to
impose additional restrictions on self-referrals where needed to
prevent abusive practices. 

   RECOMMENDATIONS TO THE
   SECRETARY OF HHS
------------------------------------------------------------ Letter :7

We recommend that the Secretary direct the Administrator of HCFA to
develop the procedures and policy guidance needed for the Medicare
contractors to (1) closely monitor Medicare imaging referral patterns
and utilization rates, (2) assure compliance with the provisions of
the self-referral ban, and (3) identify any overutilization of
imaging services ordered and provided from within physician practice
settings. 

We further recommend that the Secretary systematically review imaging
utilization information developed by HCFA and use the authority
provided under OBRA-1993 to develop any additional regulations needed
to reduce overutilization through abusive self-referral practices. 

   AGENCY COMMENTS
------------------------------------------------------------ Letter :8

HHS commented on a draft of our report and is in general agreement
with our recommendations.  See appendix IV for the agency's comments. 

---------------------------------------------------------- Letter :8.1

As arranged with your office, unless you publicly announce its
contents earlier, we plan no further distribution of this report
until 30 days after its issue date.  At that time, we will send
copies of this report to other appropriate congressional committees,
the Secretary of Health and Human Services, the Administrator of
HCFA, and the Director of the Office of Management and Budget.  We
will make additional copies available to other interested parties
upon request. 

Please call me on (202) 512-7104 if you or your staff have any
questions about this report.  Major contributors are listed in
appendix V. 

Sincerely yours,

Leslie G.  Aronovitz
Associate Director,
 Health Financing Issues

SCOPE, DATA SOURCES, AND
METHODOLOGY
=========================================================== Appendix I

This appendix describes (1) our scope and data sources, (2) our
methodology for identifying and analyzing referrals by physicians
with a financial interest in joint-venture imaging centers, and (3)
our methodology for identifying and analyzing referrals for imaging
provided within the referring physicians' practice settings. 

   SCOPE AND DATA SOURCES
--------------------------------------------------------- Appendix I:1

Several studies have investigated the effect of physician ownership
on the utilization and cost of health care services,\9 but those
studies have based their findings on analysis of relatively small
physician and patient populations.  In contrast, our study is a
large-scale analysis of physician referral patterns for all types of
diagnostic imaging services.  The study population includes all
Florida physicians who referred Medicare patients for outpatient\10

imaging services in 1990, and our data sources include the full
Florida Medicare Part B Beneficiary History File for calendar year
1990 and the Florida Medicare Provider File, both obtained from
Florida Blue Cross and Blue Shield.  By selecting Florida for our
study we were also able to make use of the extensive data on
physician ownership of Florida medical facilities compiled for the
Florida Health Care Cost Containment Board by Florida State
University.\11

While we did not formally assess the internal controls used by
Florida Blue Cross and Blue Shield or Florida State University to
ensure the accuracy of their data, we met extensively with the
officials who were responsible for collecting and maintaining these
data and reviewed their methodology and documentation.  We also
performed detailed tests and edits on computerized claims and
manually reviewed printouts of beneficiary history records to trace
individual imaging services to imaging providers and referring
physicians.  To further evaluate the accuracy of our data and
analyses, we reviewed medical and claims records from five diagnostic
imaging centers in Florida.  We also met with HCFA staff and other
researchers who have studied physician referral patterns to obtain
their technical and methodological suggestions. 

Given the size of our final database--almost 2.5 million imaging
services ordered by about 17,900 physicians--we did not attempt to
assess the medical necessity of the imaging services ordered. 
Because our study is based on the full range of diagnostic imaging
services ordered by physicians in a wide variety of primary care and
specialty practices and includes a large patient population, we
believe our study design minimizes the influence of individual
patient and physician characteristics on the overall analytical
results.  Furthermore, we structured our analyses for each type of
imaging service so that they are based on comparisons between
physicians practicing in the same specialty.  Thus, our analytical
approach reflects the variation in the use of different types of
imaging by physicians practicing in different specialties. 

--------------------
\9 See, for example, Bruce J.  Hillman, M.D., and others,
"Physicians' Utilization and Charges for Outpatient Diagnostic
Imaging in a Medicare Population," Journal of the American Medical
Association, Vol.  268, No.15 (Oct.  21, 1992), pp.  2050-2054;
Stephen E.  Radiecki and James P.  Steele, "Effect of On-site
Facilities on Use of Diagnostic Radiology by Non-radiologists,"
Investigative Radiology (Feb.  1990), pp.  190-193; Alex Swedlow and
others, "Increased Costs and Rates of Use in the California Workers'
Compensation System as a Result of Self Referral by Physicians," New
England Journal of Medicine, Vol.  327, No.  21 (Nov.  19, 1992), pp. 
1502-1524. 

\10 We use "outpatient" to describe all provider settings other than
hospital inpatient facilities--including freestanding imaging
facilities and physicians' offices, as well as hospital outpatient
departments. 

\11 Joint Ventures Among Health Care Providers in Florida, State of
Florida Health Care Cost Containment Board (Sept.  1991). 

   ANALYSIS OF REFERRED IMAGING
   SERVICES BY PHYSICIAN OWNERS
   AND NONOWNERS
--------------------------------------------------------- Appendix I:2

The first phase of our study includes only imaging services provided
by facilities outside the referring physicians' practice settings, in
facilities such as hospital outpatient departments and freestanding
(nonhospital) imaging centers.  For these analyses we grouped the
referring physicians into owner and nonowner categories based on
whether or not they had a financial interest in a freestanding
joint-venture imaging center. 

      IDENTIFYING PHYSICIANS WITH
      OWNERSHIP INTERESTS IN
      FREESTANDING IMAGING CENTERS
------------------------------------------------------- Appendix I:2.1

We identified physician owners of Florida imaging facilities using
survey information gathered by Florida State University for the
Florida Health Care Cost Containment Board during 1990.  Florida
State researchers sent surveys to all freestanding facilities
providing diagnostic imaging services, and the facilities were asked
to identify their physician owners, if any.  Of the 220 freestanding
diagnostic imaging centers in Florida in 1990, 177-- about 80
percent--responded to the survey.\12

After meeting with the principal researchers and reviewing the survey
responses, we matched ownership information from the surveys with
physician data from Florida Blue Cross and Blue Shield's Medicare
Provider File to identify the Medicare provider number(s) for each
physician owner.  We identified the Medicare provider numbers for
2,993 physician owners.  Our ownership category excludes an unknown
number of additional physicians with a financial interest in imaging
centers because (1) some medical facilities did not respond to the
Florida State survey, (2) some responding facilities indicated that
there were physicians with a financial interest in their facilities
but declined to identify those physicians, and (3) some survey
responses did not contain enough information for us to confidently
match their names to a physician in the Medicare Provider File.  Our
nonowner category includes all Florida physicians not identified as
owners.  Assuming that the unidentified physician owners, included in
the nonowner category, also had the higher imaging referral rates
associated with owners, our analyses understate the magnitude of the
higher imaging referral rates of physician owners. 

After preliminary analyses of our databases and consultations with
medical professionals, we excluded physicians practicing in
radiology, pathology, and anesthesiology from both our owner and
nonowner groups, because physicians in those specialties generally do
not refer patients for imaging services. 

For some of our analyses we also determined which of the physician
owners had a financial interest in joint-venture imaging centers that
provided MRI services, CT services, or both.  We identified these
physicians from information in the surveys from Florida State
University, the Florida Medicare Part B Provider File, and Medicare
claims submitted by imaging providers.  We could not identify the
types of services provided by 87 of the physician-owned imaging
facilities; therefore, our analyses underestimate the numbers of
physicians who invested in facilities providing MRI services, CT
services, or both. 

--------------------
\12 Florida State University researchers provided us with 17 surveys
that they received too late to include in their September 1991
report. 

      CREATING OUR DATA SET OF
      IMAGING SERVICES AND OFFICE
      VISITS
------------------------------------------------------- Appendix I:2.2

The Beneficiary History File that we obtained from Florida Blue Cross
and Blue Shield included over 50 million claims with information on
all Medicare Part B services provided in Florida between November
1989 and March 1991.  As further described below, using this database
we extracted paid claims with no obvious errors or inconsistencies
for outpatient imaging services and office visits provided in 1990. 
We used these data to calculate physicians' imaging referral
rates--the number of imaging services ordered per 1,000 office
visits.  This is a measure we have used in previous work on physician
referrals for diagnostic services.\13

We identified claims for imaging services and office visits using the
American Medical Association's 1990 Current Procedural Terminology
(CPT) manual, HCFA's 1990 procedure code listings, and guidance from
a physician consultant.  We classified all diagnostic imaging
services into seven categories designed to group similar procedures
together:  MRI, CT, ultrasound, echocardiography, diagnostic nuclear
medicine, complex X rays, and simple X rays. 

In deciding which CPT codes to include as office visits, we
considered all physician-patient encounters that provide physicians
an opportunity to refer their patients for imaging services and an
opportunity for physician-patient choice of imaging facility. 
Because hospital inpatients generally do not have an opportunity for
physician-patient choice of imaging facility, we excluded all
hospital inpatient visits and inpatient imaging services from our
analysis, regardless of the CPT codes used for those services.  For
office visits we included all CPT and HCFA codes for outpatient
medical services, consultations, preventive medicine, and case
management.  We also selectively included other CPT codes for
services such as psychiatry, ophthalmology, and critical care. 

This selection process yielded a database with about 3.5 million
imaging services and 19.4 million office visits. 

--------------------
\13 Medicare:  Referring Physician's Ownership of Laboratories and
Imaging Centers (GAO/T-HRD-89-26, June 8, 1989). 

      IDENTIFYING THE PHYSICIANS
      WHO ORDERED THE IMAGING
      SERVICES
------------------------------------------------------- Appendix I:2.3

In 1990, providers of imaging services were not required to include
the referring physicians' Medicare numbers on their claims for the
imaging services.  Some claims identified the referring physician but
others did not.  In our database of about 3.5 million imaging
services (which included in-practice imaging), the Medicare claims
for about 41 percent of those imaging services included the referring
physician number.  After analyzing a sample of the claims in our
database and consulting with other researchers, we developed and
tested various approaches for identifying the physician who ordered
the imaging service from information in the beneficiary history file. 

We did a detailed analysis of a sample of the claims that included
the referring physician number, and we traced some of those claims to
medical records at selected imaging providers.  We found that the
inclusion or exclusion of the referring physician in the claims
database appeared random; that is, it did not follow any particular
pattern that would bias our analytical results.  We also found cases
in which the referring physician was identified on a hard copy of the
claim but this information was not transcribed by Florida Blue Cross
and Blue Shield into the claims database. 

Using claims that identified the ordering physician, we simulated
various approaches for identifying the ordering physician when that
physician was not identified.  We determined that an imaging service
for a beneficiary could be reasonably matched to the physician who
ordered the service if the beneficiary had an office visit with that
physician within a "referral window" occurring from 21 days before to
7 days after the imaging service.\14

For those claims that identified the ordering physician, we included
that imaging service and ordering physician in our analysis if the
patient had an office visit with that physician within the referral
window, regardless of the number of office visits with other
physicians also within the referral window.  We excluded claims where
the identified ordering physician did not have any office visits with
the patient within the referral window because in tracing those cases
to beneficiary history records and medical files we found there was a
likelihood that the claim did not correctly identify the ordering
physician. 

For those imaging claims where there was more than one potential
ordering physician within the referral window, we further tested
various approaches for identifying which physician ordered the
imaging service.  For example, we simulated selecting the physician
with the closest office visit to the imaging service as the ordering
physician, and we compared the result to information in medical
files.  Although the overall error rate from that approach was
relatively low, we believed that there was a possibility that the
approach could introduce bias by overstating in-practice imaging
rates, especially in cases where there was an office visit and an
imaging service on the same day.  Therefore, where there was only one
potential ordering physician within the referral window, we
considered that physician the ordering physician and included that
imaging service in our analyses.  Where the imaging claim did not
identify the ordering physician and there were multiple potential
ordering physicians within the referral window we excluded that
imaging service from our analyses. 

This methodology excluded about 1 million imaging services from our
database of about 3.5 million imaging referrals.  Excluding those
imaging services generally understates the physicians' imaging rates,
but after studying the excluded imaging services we concluded that
there was no evident pattern that would introduce bias into our
analytical results. 

--------------------
\14 Physicians sometimes refer a patient for an imaging service (for
example, an X ray) shortly before the physician sees the patient. 
Thus, an imaging service can occur before the office visit with the
physician who ordered the service. 

      VERIFYING THE ACCURACY OF
      OUR REFERRAL LOGIC
------------------------------------------------------- Appendix I:2.4

To test the accuracy of our methodology for identifying the ordering
physician, we reviewed medical and billing records for about 100
imaging services from each of five Florida imaging centers.  Based on
this review, we estimate that our computerized procedures correctly
identified the ordering physician for 89 percent of the imaging
services used in our analyses.  To further confirm the accuracy of
our computerized procedures and programming, we extracted over 1,300
beneficiary claim histories and provider billing records from our
database and manually verified the match between the imaging service
and the ordering physician. 

For those cases where our referral logic may have identified an
incorrect referring physician, we believe that there was little or no
impact on our analytical results.  The large scale of our study
ensured that the incorrect attribution of a relatively small number
of imaging referrals would be distributed over a large number of
physicians across all our comparison groups.  Also, we analyzed the
claims for the services in which we discovered attribution errors,
and we found no evidence of a pattern that would bias our analytical
results. 

      ANALYZING OWNER AND NONOWNER
      IMAGING REFERRAL PATTERNS
------------------------------------------------------- Appendix I:2.5

Of the 2.5 million imaging services for which we identified the
ordering physician, we determined that about 1.2 million of those
imaging services were provided within the ordering physicians'
practice settings, as described below in a separate section of this
appendix.  The remaining 1.3 million imaging services were from
referrals to facilities outside the ordering physicians' practice
settings and were included in our analysis of owner and nonowner
referral rates. 

We arrayed and analyzed these data by type of imaging procedure and
physician specialty, as shown in appendix II, tables II.2 and II.3. 
As specified in the notes to those tables, we used cutoff criteria
for physician specialties where there was limited use of imaging. 
For each type of imaging service we also computed a weighted summary
ratio of the referral rates of owners and nonowners, weighting by the
number of imaging referrals made by each physician specialty to
account for the variation in the use of imaging--by both owners and
nonowners--among the various physician specialties.  The overall
summary of this analysis is provided in appendix II, table II.1. 

To determine if physicians with a financial interest in facilities
that provide costly high-technology services are more likely to refer
Medicare beneficiaries for those services than owners in general, we
analyzed referral rates for two additional physician groupings:  one
for physicians with a financial interest in facilities providing MRI
scans and another for physicians with a financial interest in
facilities providing CT scans.  The detailed results of those
analyses are provided in appendix II, tables II.4 and II.5. 

   ANALYSIS OF IN-PRACTICE IMAGING
--------------------------------------------------------- Appendix I:3

The second phase of our study includes the 1.2 million in-practice
imaging services provided by imaging facilities within the ordering
physicians' practice settings as well as the 1.3 million imaging
services provided outside the referring physicians' practice
settings, in facilities such as hospital outpatient departments and
freestanding imaging centers. 

      IDENTIFYING IN-PRACTICE
      IMAGING SERVICES
------------------------------------------------------- Appendix I:3.1

We classified an imaging service as in-practice if the patient
received the service from either (1) the physician who ordered the
service, (2) a physician in the same group practice as the ordering
physician, or (3) an entity (such as an imaging center or neurology
clinic) with which the ordering physician had a practice affiliation. 

To identify in-practice imaging we used computerized procedures to
compare the Medicare billing and performing provider numbers on the
imaging claim to those on the ordering physician's office visit
claim.  If either of the numbers on the imaging claim matched either
of the numbers on the office visit claim, we classified the imaging
service as in-practice; that is, the imaging service was provided by
the ordering physician or by a physician or entity (such as a clinic
or group practice) with which the ordering physician had a practice
affiliation. 

      CLASSIFYING PHYSICIANS BASED
      ON IMAGING PATTERNS
------------------------------------------------------- Appendix I:3.2

For each physician who ordered imaging services, we classified his or
her predominant imaging pattern as either in-practice or referral
separately for each of the seven types of imaging services.  For
example, if more than 50 percent of the ultrasound services ordered
by a physician were in-practice, we classified that physician's
ultrasound imaging pattern as in-practice.  Similarly, if more than
50 percent of the MRI scans ordered by that same physician were
referral, we classified that physician's MRI imaging pattern as
referral.  Thus, the same physician may be classified as having a
referral imaging pattern for one type of service and an in-practice
imaging pattern for another type of service. 

      ANALYZING OVERALL IMAGING
      UTILIZATION
------------------------------------------------------- Appendix I:3.3

Once we classified physicians based on their imaging pattern
(in-practice or referral) for each type of imaging service, we
arrayed and analyzed these data by type of imaging procedure and
physician specialty (see app.  III, tables III.2 through III.8).  As
specified in the notes to those tables, we used cutoff criteria for
physician specialties where there was limited use of imaging.  For
each type of imaging service we also computed a weighted summary
ratio of the in-practice and referral imaging rates, weighting by the
number of imaging referrals made by each physician specialty.  The
overall summary of this analysis is provided in appendix III, table
III.1. 

      LIMITATIONS OF OUR
      IN-PRACTICE ANALYSIS
------------------------------------------------------- Appendix I:3.4

Because our data are from 1990, they predate full implementation of
the unique physician identification number (UPIN) and the OBRA-1993
requirement that physicians in group practices bill under their group
practice numbers rather than their individual numbers.  Thus, in our
database the Medicare numbers on office visit and imaging claims
could have been those of the performing physician even though the
service was provided in a group practice.  Therefore, our analyses
cannot distinguish between the various types of in-practice imaging
arrangements (for example, solo practices, multi-specialty group
practices, and shared-facility arrangements). 

Also, because physicians may have used different Medicare numbers on
their office visit and imaging claims, even though both services were
provided by the same physician or group practice, our analyses
probably underestimate the number of in-practice imaging services and
the number of physicians with in-practice imaging patterns.  Thus,
the magnitude of the higher in-practice imaging rates revealed in our
analyses is probably a conservative estimate, assuming that some
physicians with in-practice imaging patterns are grouped with the
physicians with referral imaging patterns, and that those physicians
also had the higher imaging rates associated with in-practice
imaging. 

IMAGING CENTER OWNER AND NONOWNER
IMAGING RATES
========================================================== Appendix II

The tables in this appendix provide detailed comparisons between the
imaging referral rates of Florida physicians with a financial
interest in joint-venture imaging centers (referred to as owners) and
all other Florida physicians (referred to as nonowners).  As
described in appendix I, we did not have sufficient information to
identify some of the physician owners and the unidentified owners are
included in our analyses as nonowners.  This would tend to understate
the higher referral rates associated with the physician owners,
assuming that the unidentified owners had referral rates similar to
the identified owners.  Notes to the tables provide information on
the cutoff criteria for the physician specialties and imaging
referral rates included in the tables. 

Table II.1 provides a summary of the physician, imaging service, and
office visit counts for owners and nonowners, by type of imaging
service.  This table also provides summary ratios of the
owner-to-nonowner referral rates, weighted by the number of referrals
by each physician specialty to adjust for variations in imaging use
among physician specialties.  Tables II.2 and II.3 provide detailed
information for all referrals by physician specialty. 

This appendix also provides referral rates and ratios for two subsets
of physician owners--those with a financial interest in imaging
centers that offer MRIs, CTs, or both services.  Table II.4 provides
MRI referral rates by specialty for owners and nonowners of imaging
centers providing MRI services.  The summary ratio shows that MRI
owners referred twice as often for MRI scans as nonowners. 
Similarly, table II.5 provides CT referral rates by specialty for
owners and nonowners of imaging centers providing CT services.  The
summary ratio shows that CT owners referred their patients for CT
scans 29 percent more often than nonowners. 

                                                                      Table II.1
                                                       
                                                        Summary of Physician, Imaging Service,
                                                         and Office Visit Counts, by Type of
                                                         Imaging Service for Referred Imaging
                                                                       Services

                                                                                                                                             Ratio of
                                                                                                                                            owner-to-
                                                                                                                                             nonowner
                                                                                                                                             referral
Type of service       Owners      Nonowners          Total    Owners     Nonowners       Total      Owners     Nonowners        Total         rates\a
------------------  --------  -------------  -------------  --------  ------------  ----------  ----------  ------------  -----------  --------------
MRI                    2,122         11,697         13,819    11,650        22,099      33,749   2,258,613     9,769,738   12,028,351            1.54
CT                     2,347         12,391         14,738    30,800        83,315     114,115   2,302,365     9,816,887   12,119,252            1.27
Ultrasound             2,106         12,332         14,438    24,204        75,961     100,165   2,176,944    10,263,263   12,440,207            1.22
Echocardiography       1,673         11,164         12,837    13,550        40,831      54,381   1,982,142     9,932,889   11,915,031            1.27
Nuclear medicine       2,129         12,091         14,220    20,060        48,753      68,813   2,272,806    10,513,993   12,786,799            1.37
Complex X ray          2,265         11,375         13,640    29,024        88,273     117,297   2,190,622     8,189,197   10,379,819            1.22
Simple X ray           2,285         12,858         15,143   146,359       600,493     746,852   2,304,395    10,648,918   12,953,313            1.04
-----------------------------------------------------------------------------------------------------------------------------------------------------
Note:  For each type of imaging service (for example, MRI or CT) this
summary excludes physicians, imaging services and office visits for
physician specialties where (1) the physicians in that specialty
accounted for less than 0.5 percent of the total imaging services
ordered for that type of imaging or (2) there were no physicians in
either the owner or nonowner categories.  After applying this cutoff
criteria, this summary includes about 1.23 million referred imaging
services, or about 96 percent of the 1.28 million referred imaging
services in our database. 

\a The ratios of owner-to-nonowner referral rates are weighted by
physician specialty.  For each type of imaging service (for example,
MRI or CT), the weighting factor for each specialty is the number of
the total imaging services of that type that were ordered by the
physicians in that specialty.  We computed weighted ratios to adjust
for differences in the use of imaging among physician specialties. 

                                                                      Table II.2
                                                       
                                                        Imaging Referrals per Thousand Office
                                                       Visits, by Referring Physician Specialty
                                                                 and Ownership Status

                                     Number
Referring                                of
physician           Ownership      physicia      Number of     MRI      CT         Nuclear                                    Complex X      Simple X
specialty           status               ns  office visits   scans   scans        medicine   Echocardiography  Ultrasound          rays          rays
------------------  -------------  --------  -------------  ------  ------  --------------  -----------------  ----------  ------------  ------------
Cardiovascular      Owner               159        206,579    1.31    9.46           14.98              14.12       11.16         10.54         49.81
 disease
                    Nonowner            706        554,691    0.80    5.79           12.39              12.80        7.05          7.37         48.69
Endocrinology       Owner                19         14,074      \a    8.88            4.69               1.07        3.98          4.48        167.83
                    Nonowner            326        184,882      \a   11.81            2.89               2.44        3.95          5.38        206.14
Family practice     Owner               229        380,872    1.97    8.54            4.65               5.32        9.22         12.63         67.14
                    Nonowner          1,681      1,508,811    1.39    6.56            3.01               4.32        8.50          9.61         66.36
Gastroenterology    Owner                71         61,301    1.76   25.90            8.42               4.98       25.38         31.16         60.70
                    Nonowner            278        136,750    0.72   28.98            6.49               2.12       21.83         35.96         49.85
General practice    Owner               185        219,725    1.84    7.70            3.85               4.52        8.35          9.73         78.84
                    Nonowner          1,960      1,629,224    0.85    5.80            2.58               4.88        7.64          7.72         75.29
General surgery     Owner               138         41,950    4.46   22.05           10.51               1.53       18.16         34.28        127.37
                    Nonowner            921        304,775    0.92   13.09            5.63               3.47       11.80         21.00         94.83
Geriatrics          Owner                 5         12,319      \a      \a              \a                 \a          \a            \a        108.21
                    Nonowner             19         37,367      \a      \a              \a                 \a          \a            \a        107.80
Gynecology          Owner                 7          1,564      \a      \a              \a                 \a        9.59            \a            \a
 (osteopath)
                    Nonowner             62         14,477      \a      \a              \a                 \a       36.33            \a            \a
Internal medicine   Owner               476        640,063    2.31   12.05            8.03               9.38       11.30         13.29         70.62
                    Nonowner          2,364      2,290,218    1.81    9.47            5.78               6.01        9.28         10.70         67.49
Maxillofacial       Owner                78        106,359    6.03   45.86           20.91               2.59        5.99          6.07         82.21
 surgery
                    Nonowner            212        223,346    4.30   37.49           16.78               1.39        4.62          5.87         74.98
Nephrology          Owner                30         23,130    4.02   12.54           15.39              11.59       24.60         12.58         96.24
                    Nonowner             95         51,949    1.92    7.51           10.51               3.41       14.86          8.93         69.68
Neurological        Owner                64         13,943   66.99   54.36           18.65                 \a          \a         19.22            \a
 surgery
                    Nonowner            108         18,490   53.22   42.73           10.76                 \a          \a         19.20            \a
Neurology           Owner               134         72,604   47.09   23.86            4.77               2.26          \a          3.33         31.00
                    Nonowner            259        122,395   38.18   23.47            3.64               2.25          \a          3.19         37.02
Neuropsychiatry     Owner                20         43,150    5.56    5.28            5.93               1.67        3.29          4.17         26.79
                    Nonowner            106        168,941    4.90    5.01            5.89               2.39        4.00          3.10         57.19
Obstetrics/         Owner               215         33,213      \a    6.47              \a                 \a       24.75          7.05        106.68
 gynecology
                    Nonowner            856        116,048      \a    6.26              \a                 \a       22.10          6.21        102.72
Oncology/           Owner                 2          2,982      \a  107.98              \a                 \a          \a            \a            \a
 hematology
                    Nonowner             24         21,522      \a   22.63              \a                 \a          \a            \a            \a
Ophthalmology       Owner                38         65,165    1.30    0.60            0.41               0.34        2.26            \a          8.73
                    Nonowner            775      1,380,109    0.36    0.75            0.38               0.50        1.03            \a          9.76
Orthopedic surgery  Owner               238        127,820   16.88    9.75           12.84                 \a        1.24          4.83         38.09
                    Nonowner            656        295,546   13.01    7.57           10.35                 \a        1.28          4.44         41.47
Otolaryngology      Owner                47         44,092    7.17   13.06            1.59                 \a          \a            \a         29.44
                    Nonowner            310        240,370    4.10   11.91            1.27                 \a          \a            \a         29.75
Podiatry            Owner                 6          7,870      \a      \a            2.16               0.64        1.40            \a         28.34
                    Nonowner            615        844,265      \a      \a            0.48               0.56        1.04            \a          8.23
Preventive          Owner                18         29,445    3.67    9.17            9.10               4.69        9.75          7.68         45.58
 medicine
                    Nonowner            106         97,486    1.83    6.49            5.29               3.37        8.54          7.33         48.22
Psychiatry          Owner                18          7,751    5.03      \a              \a               0.39          \a            \a            \a
                    Nonowner            547        284,892    0.60      \a              \a               1.14          \a            \a            \a
Pulmonary disease   Owner                54         62,104    2.58   17.52            7.97               4.43        5.27          8.61         71.88
                    Nonowner            213        150,155    1.01   15.81            7.53               4.76        5.03          6.42         93.72
Thoracic surgery    Owner                12          1,730      \a      \a              \a                 \a          \a         26.59            \a
                    Nonowner            128         23,900      \a      \a              \a                 \a          \a         32.76            \a
Urology             Owner               125        112,560    2.29   16.56           19.78                 \a       34.02         41.69         40.25
                    Nonowner            400        311,590    0.87   14.10           15.70                 \a       26.86         40.91         42.38
-----------------------------------------------------------------------------------------------------------------------------------------------------
\a For each type of imaging service (for example, MRI or CT), this
analysis excludes imaging referral rates where (1) either owners or
nonowners within a specialty made no referrals or (2) the referrals
by physicians in the specialty for owners and nonowners combined
accounted for less than 0.5 percent of all the referrals for that
type of imaging service.  The referrals included in this analysis
account for 97 percent of the MRI scans we matched to a referring
physician, 96 percent of the CT scans; 97 percent of the nuclear
medicine scans; 97 percent of the echocardiography services; 97
percent of the ultrasound services; 97 percent of the complex X rays;
and 96 percent of the simple X rays. 

                                                                      Table II.3
                                                       
                                                         Ratio of Owner-to-Nonowner Referral
                                                       Rates, by Referring Physician Specialty

                                     Number
Referring                                of
physician           Ownership      physicia      Number of     MRI      CT         Nuclear                                    Complex X      Simple X
specialty           status               ns  office visits   scans   scans        medicine   Echocardiography  Ultrasound          rays          rays
------------------  -------------  --------  -------------  ------  ------  --------------  -----------------  ----------  ------------  ------------
Cardiovascular      Owner               159        206,579    1.63    1.63            1.21               1.10        1.58          1.43          1.02
 disease
                    Nonowner            706        554,691
Endocrinology       Owner                19         14,074      \a    0.75            1.62               0.44        1.01          0.83          0.81
                    Nonowner            326        184,882
Family practice     Owner               229        380,872    1.42    1.30            1.54               1.23        1.08          1.31          1.01
                    Nonowner          1,681      1,508,811
Gastroenterology    Owner                71         61,301    2.46    0.89            1.30               2.35        1.16          0.87          1.22
                    Nonowner            278        136,750
General practice    Owner               185        219,725    2.17    1.33            1.49               0.93        1.09          1.26          1.05
                    Nonowner          1,960      1,629,224
General surgery     Owner               138         41,950    4.87    1.68            1.87               0.44        1.54          1.63          1.34
                    Nonowner            921        304,775
Geriatrics          Owner                 5         12,319      \a      \a              \a                 \a          \a            \a          1.00
                    Nonowner             19         37,367
Gynecology          Owner                 7          1,564      \a      \a              \a                 \a        0.26            \a            \a
 (osteopath)
                    Nonowner             62         14,477
Internal medicine   Owner               476        640,063    1.27    1.27            1.39               1.56        1.22          1.24          1.05
                    Nonowner          2,364      2,290,218
Maxillofacial       Owner                78        106,359    1.40    1.22            1.25               1.86        1.30          1.03          1.10
 surgery
                    Nonowner            212        223,346
Nephrology          Owner                30         23,130    2.09    1.67            1.46               3.40        1.66          1.41          1.38
                    Nonowner             95         51,949
Neurological        Owner                64         13,943    1.26    1.27            1.73                 \a          \a          1.00            \a
 surgery
                    Nonowner            108         18,490
Neurology           Owner               134         72,604    1.23    1.02            1.31               1.01          \a          1.05          0.84
                    Nonowner            259        122,395
Neuropsychiatry     Owner                20         43,150    1.13    1.05            1.01               0.70        0.82          1.34          0.47
                    Nonowner            106        168,941
Obstetrics/         Owner               215         33,213      \a    1.03              \a                 \a        1.12          1.13          1.04
 gynecology
                    Nonowner            856        116,048
Oncology/           Owner                 2          2,982      \a    4.77              \a                 \a          \a            \a            \a
 hematology
                    Nonowner             24         21,522
Ophthalmology       Owner                38         65,165    3.62    0.80            1.09               0.67        2.18            \a          0.89
                    Nonowner            775      1,380,109
Orthopedic surgery  Owner               238        127,820    1.30    1.29            1.24                 \a        0.97          1.09          0.92
                    Nonowner            656        295,546
Otolaryngology      Owner                47         44,092    1.75    1.10            1.25                 \a          \a            \a          0.99
                    Nonowner            310        240,370
Podiatry            Owner                 6          7,870      \a      \a            4.54               1.14        1.34            \a          3.44
                    Nonowner            615        844,265
Preventive          Owner                18         29,445    2.01    1.41            1.72               1.39        1.14          1.05          0.95
 medicine
                    Nonowner            106         97,486
Psychiatry          Owner                18          7,751    8.38      \a              \a               0.34          \a            \a            \a
                    Nonowner            547        284,892
Pulmonary disease   Owner                54         62,104    2.56    1.11            1.06               0.93        1.05          1.34          0.77
                    Nonowner            213        150,155
Thoracic surgery    Owner                12          1,730      \a      \a              \a                 \a          \a          0.81            \a
                    Nonowner            128         23,900
Urology             Owner               125        112,560    2.63    1.17            1.26                 \a        1.27          1.02          0.95
                    Nonowner            400        311,590
All listed          Owner             2,388      2,332,365  1.54\b  1.27\b          1.37\b             1.27\b      1.22\b        1.22\b        1.04\b
 specialties
                    Nonowner         13,727     11,012,199
-----------------------------------------------------------------------------------------------------------------------------------------------------
\a For each type of imaging service (for example, MRI or CT), this
analysis excludes imaging referrals where (1) either owners or
nonowners within a specialty made no referrals or (2) the referrals
by physicians in the specialty for owners and nonowners combined
accounted for less than 0.5 percent of all the referrals for that
type of imaging service. 

\b The ratios of owner-to-nonowner referrals for all specialties
combined are weighted ratios, based on the number of each type of
imaging service referrals by each specialty. 

                                        Table II.4
                         
                          MRI Referrals, by Referring Physician
                            Specialty and MRI Ownership Status

                                                                   MRI
                                    Number                   referrals       Ratio of MRI
Referring                               of     Number of     per 1,000          owner-to-
physician         MRI ownership   physicia        office        office  nonowner referral
specialty         status                ns        visits        visits              rates
----------------  --------------  --------  ------------  ------------  -----------------
Cardiovascular    Owner                 61        69,952          1.63               1.98
 disease
                  Nonowner             777       650,302          0.82
Family practice   Owner                 56        80,827          2.07               1.40
                  Nonowner           1,831     1,766,487          1.48
Gastroenterology  Owner                 29        29,930          2.71               3.61
                  Nonowner             310       159,988          0.75
General practice  Owner                 79        82,868          2.65               3.00
                  Nonowner           2,040     1,728,324          0.89
General surgery   Owner                 57        18,859          8.32               9.26
                  Nonowner             983       322,698          0.90
Internal          Owner                191       232,022          3.43               1.91
 medicine
                  Nonowner           2,596     2,630,615          1.79
Maxillofacial     Owner                 40        48,087          7.17               1.61
 surgery
                  Nonowner             239       263,152          4.45
Nephrology        Owner                 10         9,988          6.41               3.27
                  Nonowner             107        56,623          1.96
Neurological      Owner                 49         8,832         71.78               1.38
 surgery
                  Nonowner             115        21,544         52.03
Neurology         Owner                 89        45,802         52.31               1.36
                  Nonowner             282       136,066         38.55
Neuropsychiatry   Owner                 16        33,486          5.70               1.16
                  Nonowner             110       178,605          4.91
Ophthalmology     Owner                 18        34,358          2.30               6.43
                  Nonowner             787     1,398,387          0.36
Orthopedic        Owner                146        77,329         20.34               1.59
 surgery
                  Nonowner             721       333,603         12.78
Otolaryngology    Owner                 25        21,513          9.30               2.22
                  Nonowner             329       258,038          4.19
Preventive        Owner                 10        16,331          4.10               2.04
 medicine
                  Nonowner             112       107,171          2.02
Psychiatry        Owner                 12         4,194          8.11              13.31
                  Nonowner             551       287,307          0.61
Pulmonary         Owner                 29        29,148          3.05               2.60
 disease
                  Nonowner             232       173,906          1.17
Urology           Owner                 35        32,568          4.97               5.60
                  Nonowner             474       378,486          0.89
All listed        Owner                952       876,094            --             2.02\a
 specialties
                  Nonowner          12,596    10,851,302            --
-----------------------------------------------------------------------------------------
Notes:  For some physicians with an investment interest in an imaging
center, we could not readily determine if the center offered MRI
services.  Those physicians were excluded from this analysis.

This analysis excludes physician specialties where (1) either owners
or nonowners within the specialty made no MRI referrals or (2) the
MRI referrals by physicians in the specialty for owners and nonowners
combined accounted for less than 0.5 percent of all the MRI referrals
we matched to a referring physician.  The MRI referrals included in
this analysis account for 93 percent of all the MRI referrals we
matched to a referring physician. 

\a The ratio of MRI owner-to-nonowner referral rates for all
specialties combined is a weighted ratio based on the number of MRI
referrals by each specialty. 

                                        Table II.5
                         
                           CT Referrals, by Referring Physician
                            Specialty and CT Ownership Status

                                    Number                CT referrals        Ratio of CT
Referring                               of     Number of     per 1,000          owner-to-
physician         CT ownership    physicia        office        office  nonowner referral
specialty         status                ns        visits        visits              rates
----------------  --------------  --------  ------------  ------------  -----------------
Cardiovascular    Owner                 83       105,403          9.93               1.70
 disease
                  Nonowner             755       614,851          5.83
Endocrinology     Owner                 17        13,125          9.37               0.79
                  Nonowner             327       185,057         11.81
Family practice   Owner                122       176,933          9.17               1.36
                  Nonowner           1,765     1,670,381          6.75
Gastroenterology  Owner                 43        34,882         24.28               0.84
                  Nonowner             296       155,036         28.77
General practice  Owner                107       114,686          7.40               1.27
                  Nonowner           2,012     1,696,506          5.85
General surgery   Owner                 84        24,352         19.51               1.41
                  Nonowner             956       317,205         13.82
Internal          Owner                295       404,157         12.63               1.32
 medicine
                  Nonowner           2,492     2,458,480          9.57
Maxillofacial     Owner                 58        76,641         50.21               1.31
 surgery
                  Nonowner             221       234,598         38.21
Neurological      Owner                 41         9,489         57.22               1.36
 surgery
                  Nonowner             123        20,887         42.23
Neurology         Owner                 80        43,979         26.90               1.19
                  Nonowner             291       137,889         22.67
Neuropsychiatry   Owner                 14        29,782          5.24               1.04
                  Nonowner             112       182,309          5.04
Obstetrics/       Owner                114        18,402          6.63               1.04
 gynecology
                  Nonowner             931       126,587          6.36
Ophthalmology     Owner                 23        32,019          0.62               0.84
                  Nonowner             782     1,400,726          0.74
Orthopedic        Owner                139        73,961         12.36               1.67
 surgery
                  Nonowner             728       336,971          7.42
Otolaryngology    Owner                 32        28,261         12.70               1.07
                  Nonowner             322       251,290         11.89
Preventive        Owner                 12        20,173         11.25               1.78
 medicine
                  Nonowner             110       103,329          6.32
Pulmonary         Owner                 38        42,574         19.97               1.26
 disease
                  Nonowner             223       160,480         15.80
Urology           Owner                 67        66,667         18.37               1.32
                  Nonowner             442       344,387         13.93
All listed        Owner              1,369     1,315,486            --             1.29\a
 specialties
                  Nonowner          12,888    10,396,969            --
-----------------------------------------------------------------------------------------
Notes:  For some physicians with an investment interest in an imaging
center, we could not readily determine if the center offered CT
services.  Those physicians were excluded from this analysis.

This analysis excludes physician specialties where (1) either owners
or nonowners within the specialty made no CT referrals, (2) the CT
referrals by physicians in the specialty for owners and nonowners
combined accounted for less than 0.5 percent of all the CT referrals
we matched to a referring physician, or (3) there were fewer than 10
physicians in either category.  The CT referrals included in this
analysis account for 92 percent of all the CT referrals we matched to
a referring physician. 

\a The ratio of CT owner-to-nonowner referral rates for all
specialties combined is a weighted ratio based on the number of CT
referrals by each specialty. 

IN-PRACTICE AND REFERRAL IMAGING
RATES
========================================================= Appendix III

The tables in this appendix provide detailed comparisons between
in-practice and referral imaging rates for Florida physicians.  As
described in appendix I, we classified each physician's predominant
imaging pattern as either in-practice or referral for each of seven
types of imaging services. 

Table III.1 provides a summary of the physician, imaging service, and
office visit counts for in-practice and referring physicians by type
of imaging service.  This table also provides summary ratios of the
in-practice and referral rates, weighted by the number of imaging
services ordered by each physician specialty to adjust for variations
in the use of imaging among physician specialties.  The summary
ratios show that in-practice imaging rates exceeded referral imaging
rates for all types of imaging services.  The in-practice rates were
about 3 times higher for MRI scans; about 2 times higher for CT
scans; 4.5 to 5 times higher for ultrasound, echocardiography, and
diagnostic nuclear medicine imaging; and about 2 times higher for
complex and simple X rays. 

Tables III.2 through III.8 provide detailed information on imaging
rates by physician specialty for each of seven types of diagnostic
imaging services--MRI, CT, ultrasound, echocardiography, diagnostic
nuclear medicine, complex X rays, and simple X rays. 

                                                                     Table III.1
                                                       
                                                        Summary of Physician, Imaging Service,
                                                         and Office Visit Counts, by Type of
                                                         Imaging Service for In-practice and
                                                              Referred Imaging Services

                                                                                                                                         Ratio of in-
                                                                                                                                         practice-to-
                                                                                                                                             referral
                         In-                                     In-                                   In-                              imaging rates
Type of service     practice       Referral          Total  practice      Referral       Total    practice      Referral        Total              \a
------------------  --------  -------------  -------------  --------  ------------  ----------  ----------  ------------  -----------  --------------
MRI                      169         13,650         13,819     2,622        33,939      36,561     142,985    11,885,366   12,028,351            3.06
CT                       310         14,360         14,670     7,273       112,171     119,444     291,756    11,792,169   12,083,925            1.95
Ultrasound             1,646         10,899         12,545   112,030        94,169     206,199   2,254,372     8,695,337   10,949,709            5.13
Echocardiography       1,185          9,995         11,180    70,442        51,576     122,018   1,327,817     9,031,389   10,359,206            4.78
Nuclear medicine         418         13,677         14,095    15,193        67,406      82,599     390,600    12,321,120   12,711,720            4.52
Complex X ray            773         11,879         12,652    19,595       116,389     135,984     699,675     9,534,698   10,234,373            1.92
Simple X ray           4,897         10,222         15,119   971,140       646,856   1,617,996   4,824,447     8,079,180   12,903,627            2.10
-----------------------------------------------------------------------------------------------------------------------------------------------------
Note:  For each type of imaging service (for example, MRI or CT),
this summary excludes physicians, imaging services, and office visits
for physician specialties where (1) the physicians in that specialty
accounted for less than 0.5 percent of the total imaging services
ordered for that type of imaging or (2) there were no physicians in
either the in-practice or referral categories.  After applying these
cutoff criteria, this summary includes about 2,321,000 imaging
services, or about 95 percent of the 2,441,000 imaging services in
our database. 

\a The ratios of in-practice-to-referral imaging rates are weighted
by physician specialty.  For each type of imaging service (for
example, MRI or CT), the weighting factor for each specialty is the
number of the total imaging services of that type that were ordered
by the physicians in that specialty.  We computed a weighted ratio to
adjust for differences in the use of imaging among physician
specialties. 

                                       Table III.2
                         
                            MRI In-practice and Referral Rates

                                    Number                   MRI scans
                                        of     Number of     per 1,000       Ratio of in-
Physician         Imaging         physicia        office        office          practice-
specialty\a       pattern               ns        visits        visits  to-referral rates
----------------  --------------  --------  ------------  ------------  -----------------
Cardiovascular    In-practice            9         3,729          9.65              10.20
 disease
                  Referral             856       757,541          0.95
Family practice   In-practice            4         2,987          2.68               1.77
                  Referral           1,906     1,886,696          1.51
Gastroenterology  In-practice            7         4,779          5.65               5.30
                  Referral             342       193,272          1.07
General practice  In-practice            5         4,112          4.38               4.50
                  Referral           2,140     1,844,837          0.97
General surgery   In-practice            6         9,353         12.40               9.00
                  Referral           1,053       337,372          1.38
Internal          In-practice           50        47,989          7.73               3.96
 medicine
                  Referral           2,790     2,882,292          1.95
Maxillofacial     In-practice            7         5,969         14.91               3.02
 surgery
                  Referral             283       323,736          4.93
Nephrology        In-practice            2         1,715         25.66               9.75
                  Referral             123        73,364          2.63
Neurological      In-practice            7         1,771         90.91               1.44
 surgery
                  Referral             165        30,662         63.24
Neurology         In-practice           25        15,558         81.31               1.77
                  Referral             368       179,441         45.84
Neuropsychiatry   In-practice            3         4,212          6.89               1.33
                  Referral             123       207,879          5.17
Ophthalmology     In-practice            6         9,844          3.05               7.49
                  Referral             807     1,435,430          0.41
Orthopedic        In-practice           13         7,391         31.25               2.15
 surgery
                  Referral             881       415,975         14.51
Otolaryngology    In-practice            7         6,065         12.04               2.58
                  Referral             350       278,397          4.66
Preventive        In-practice            6         7,720          8.42               3.56
 medicine
                  Referral             118       119,211          2.37
Psychiatry        In-practice            2           484          8.26              11.50
                  Referral             563       292,159          0.72
Pulmonary         In-practice            2         1,064         21.62              14.68
 disease
                  Referral             265       211,195          1.47
Urology           In-practice            8         8,243          3.88               3.02
                  Referral             517       415,907          1.29
All listed        In-practice          169       142,985            --             3.06\b
 specialties
                  Referral          13,650    11,885,366            --
-----------------------------------------------------------------------------------------
\a This table excludes specialties where (1) physicians in one or
both of the comparison groups within the specialty did not order any
MRI scans, (2) the number of MRI scans ordered by the physicians in
the specialty accounted for less than 0.5 percent of the total MRI
scans used in our analysis, or (3) fewer than 10 physicians in that
specialty ordered MRI scans.  The specialties included in this table
accounted for over 95 percent of the MRI scans used in our analyses. 

\b The ratio for all specialties combined is weighted by the number
of MRI scans ordered by physicians in each specialty. 

                                       Table III.3
                         
                            CT In-practice and Referral Rates

                                    Number
                                        of     Number of  CT scans per       Ratio of in-
Physician         Imaging         physicia        office  1,000 office       practice-to-
specialty\a       pattern               ns        visits        visits     referral rates
----------------  --------------  --------  ------------  ------------  -----------------
Cardiovascular    In-practice           16         9,064         15.56               2.26
 disease
                  Referral             849       752,206          6.89
Endocrinology     In-practice            5         7,016          8.41               0.70
                  Referral             340       191,940         12.02
Family practice   In-practice           20        27,808         11.94               1.69
                  Referral           1,890     1,861,875          7.05
Gastroenterology  In-practice           12         7,509         40.48               1.39
                  Referral             337       190,542         29.12
General practice  In-practice            7         8,992         11.12               1.84
                  Referral           2,138     1,839,957          6.06
General surgery   In-practice           16         8,715         30.06               2.07
                  Referral           1,043       338,010         14.51
Internal          In-practice           87       100,953         20.32               1.96
 medicine
                  Referral           2,753     2,829,328         10.36
Maxillofacial     In-practice           11        11,997         80.77               1.94
 surgery
                  Referral             279       317,708         41.58
Nephrology        In-practice            4         3,194         28.18               2.97
                  Referral             121        71,885          9.50
Neurological      In-practice            9         2,345         90.41               1.75
 surgery
                  Referral             163        30,088         51.75
Neurology         In-practice           43        24,604         59.22               2.22
                  Referral             350       170,395         26.71
Neuropsychiatry   In-practice            5         9,801         12.75               2.39
                  Referral             121       202,290          5.33
Obstetrics/       In-practice           13         3,125         17.28               2.68
 gynecology
                  Referral           1,058       146,136          6.45
Ophthalmology     In-practice           12        19,755          4.96               6.63
                  Referral             801     1,425,519          0.75
Orthopedic        In-practice           16        10,676         13.68               1.61
 surgery
                  Referral             878       412,690          8.50
Otolaryngology    In-practice            6         4,990         28.86               2.34
                  Referral             351       279,472         12.34
Preventive        In-practice            9        12,919         14.71               1.87
 medicine
                  Referral             115       114,012          7.85
Pulmonary         In-practice            6         6,398         23.91               1.43
 disease
                  Referral             261       205,861         16.78
Urology           In-practice           13        11,895         32.45               2.14
                  Referral             512       412,255         15.18
All listed        In-practice          310       291,756            --             1.95\b
 specialties
                  Referral          14,360    11,792,169            --
-----------------------------------------------------------------------------------------
\a This table excludes specialties where (1) physicians in one or
both of the comparison groups within the specialty did not order any
CT scans, (2) the number of CT scans ordered by the physicians in the
specialty accounted for less than 0.5 percent of the total CT scans
used in our analyses, or (3) fewer than 10 physicians in that
specialty ordered CT scans.  The specialties included in this table
accounted for over 95 percent of the CT scans used in our analyses. 

\b The ratio for all specialties combined is weighted by the number
of CT scans ordered by physicians in each specialty. 

                                       Table III.4
                         
                           Ultrasound In-practice and Referral
                                          Rates

                                                            Ultrasound
                                    Number                    services
                                        of     Number of           per       Ratio of in-
Physician         Imaging         physicia        office  1,000 office       practice-to-
specialty\a       pattern               ns        visits        visits     referral rates
----------------  --------------  --------  ------------  ------------  -----------------
Cardiovascular    In-practice           87       101,515         36.55               4.02
 disease
                  Referral             778       659,755          9.10
Family practice   In-practice           67        97,290         15.82               1.74
                  Referral           1,843     1,792,393          9.07
Gastroenterology  In-practice           20        15,222         77.72               3.13
                  Referral             329       182,829         24.82
General practice  In-practice           78        96,784         29.01               3.55
                  Referral           2,067     1,752,165          8.18
General surgery   In-practice           55        22,614         41.26               2.98
                  Referral           1,004       324,111         13.84
Internal          In-practice          189       243,400         27.30               2.59
 medicine
                  Referral           2,651     2,686,881         10.56
Maxillofacial     In-practice           11        14,669         13.98               2.64
 surgery
                  Referral             279       315,036          5.30
Nephrology        In-practice            3         2,453         40.77               2.14
                  Referral             122        72,626         19.03
Neuropsychiatry   In-practice            9        16,245          7.94               1.90
                  Referral             117       195,846          4.18
Obstetrics/       In-practice          111        17,168         34.42               1.31
 gynecology
                  Referral             960       132,093         26.28
Ophthalmology     In-practice          698     1,347,767         49.33              10.59
                  Referral             115        97,507          4.66
Preventive        In-practice           13        18,390         23.16               2.29
 medicine
                  Referral             111       108,541         10.12
Pulmonary         In-practice           10        13,197         22.20               4.17
 disease
                  Referral             257       199,062          5.32
Urology           In-practice          263       247,658        108.98               1.88
                  Referral             262       176,492         58.04
All listed        In-practice        1,646     2,254,372            --             5.13\b
 specialties
                  Referral          10,899     8,695,337            --
-----------------------------------------------------------------------------------------
\a This table excludes specialties where (1) physicians in one or
both of the comparison groups within the specialty did not order any
ultrasound services, (2) the number of ultrasound services ordered by
the physicians in the specialty accounted for less than 0.5 percent
of the total ultrasound services used in our analyses, or (3) fewer
than 10 physicians in that specialty ordered ultrasound services. 
The specialties included in this table accounted for over 95 percent
of the ultrasound services used in our analyses. 

\b The ratio for all specialties combined is weighted by the number
of ultrasound services ordered by physicians in each specialty. 

                                       Table III.5
                         
                             Echocardiography In-practice and
                                      Referral Rates

                                                          Echocardiogr
                                    Number                     ams per
                                        of     Number of         1,000       Ratio of in-
Physician         Imaging         physicia        office        office       practice-to-
specialty\a       pattern               ns        visits        visits     referral rates
----------------  --------------  --------  ------------  ------------  -----------------
Cardiovascular    In-practice          464       460,045         80.80               2.63
 disease
                  Referral             401       301,225         30.76
Family practice   In-practice           78        93,240         26.36               5.63
                  Referral           1,832     1,796,443          4.68
Gastroenterology  In-practice           12         7,211         14.15               4.53
                  Referral             337       190,840          3.12
General practice  In-practice           84       106,783         40.77               7.90
                  Referral           2,061     1,742,166          5.16
General surgery   In-practice           31        15,744         15.43               4.61
                  Referral           1,028       330,981          3.35
Internal          In-practice          422       523,060         46.29               5.68
 medicine
                  Referral           2,418     2,407,221          8.14
Maxillofacial     In-practice           20        27,258          6.93               3.51
 surgery
                  Referral             270       302,447          1.98
Nephrology        In-practice           10        13,886         19.37               2.75
                  Referral             115        61,193          7.04
Neurology         In-practice           21        14,810         15.80               6.59
                  Referral             372       180,189          2.40
Ophthalmology     In-practice           15        27,314          4.58               9.08
                  Referral             798     1,417,960          0.50
Preventive        In-practice           13        22,133         14.32               3.28
 medicine
                  Referral             111       104,798          4.37
Pulmonary         In-practice           15        16,333         47.02               9.63
 disease
                  Referral             252       195,926          4.88
All listed        In-practice        1,185     1,327,817            --             4.78\b
 specialties
                  Referral           9,995     9,031,389            --
-----------------------------------------------------------------------------------------
\a This table excludes specialties where (1) physicians in one or
both of the comparison groups within the specialty did not order any
echocardiograms, (2) the number of echocardiograms ordered by the
physicians in the specialty accounted for less than 0.5 percent of
the total echocardiograms used in our analyses, or (3) fewer than 10
physicians in that specialty ordered echocardiograms.  The
specialties included in this table accounted for over 96 percent of
the echocardiograms used in our analyses. 

\b The ratio for all specialties combined is weighted by the number
of echocardiograms ordered by physicians in each specialty. 

                                       Table III.6
                         
                             Nuclear Medicine In-practice and
                                      Referral Rates

                                    Number                     Nuclear
                                        of     Number of     scans per       Ratio of in-
Physician         Imaging         physicia        office  1,000 office       practice-to-
specialty\a       pattern               ns        visits        visits     referral rates
----------------  --------------  --------  ------------  ------------  -----------------
Cardiovascular    In-practice          141       113,597         77.04               5.21
 disease
                  Referral             724       647,673         14.79
Endocrinology     In-practice            4         6,479          2.93               0.94
                  Referral             341       192,477          3.12
Family practice   In-practice           12        17,480         13.79               4.07
                  Referral           1,898     1,872,203          3.38
Gastroenterology  In-practice           11         6,575         11.41               1.55
                  Referral             338       191,476          7.36
General practice  In-practice           16        19,969         45.32              16.50
                  Referral           2,129     1,828,980          2.75
General surgery   In-practice           17        10,908          6.97               1.08
                  Referral           1,042       335,817          6.42
Internal          In-practice          116       112,392         25.98               4.02
 medicine
                  Referral           2,724     2,817,889          6.46
Maxillofacial     In-practice            9        10,327         26.24               1.40
 surgery
                  Referral             281       319,378         18.73
Neurological      In-practice            6         1,681         16.06               1.08
 surgery
                  Referral             166        30,752         14.86
Neurology         In-practice           12         6,799          7.65               1.80
                  Referral             381       188,200          4.25
Neuropsychiatry   In-practice           10        22,541         26.75               4.18
                  Referral             116       189,550          6.40
Ophthalmology     In-practice           12        17,368          2.59               6.67
                  Referral             801     1,427,906          0.39
Orthopedic        In-practice           16         9,580         15.34               1.35
 surgery
                  Referral             878       413,786         11.39
Otolaryngology    In-practice            5         3,471          6.63               4.89
                  Referral             352       280,991          1.36
Podiatry          In-practice            1         2,064          0.48               0.98
                  Referral             620       850,071          0.49
Preventive        In-practice           11        12,022         30.94               4.46
 medicine
                  Referral             113       114,909          6.94
Pulmonary         In-practice            6         6,731         25.85               3.27
 disease
                  Referral             261       205,528          7.90
Urology           In-practice           13        10,616         46.25               2.68
                  Referral             512       413,534         17.29
All listed        In-practice          418       390,600            --             4.52\b
 specialties
                  Referral          13,677    12,321,120            --
-----------------------------------------------------------------------------------------
\a This table excludes specialties where (1) physicians in one or
both of the comparison groups within the specialty did not order any
nuclear medicine scans, (2) the number of nuclear medicine scans
ordered by the physicians in the specialty accounted for less than
0.5 percent of the total nuclear medicine scans used in our analyses,
or (3) fewer than 10 physicians in that specialty ordered nuclear
medicine scans.  The specialties included in this table accounted for
96 percent of the nuclear medicine scans used in our analyses. 

\b The ratio for all specialties combined is weighted by the number
of nuclear medicine scans ordered by physicians in each specialty. 

                                       Table III.7
                         
                          Complex X ray In-practice and Referral
                                          Rates

                                                             Complex X
                                    Number                        rays
                                        of     Number of     per 1,000       Ratio of in-
Physician         Imaging         physicia        office        office       practice-to-
specialty\a       pattern               ns        visits        visits     referral rates
----------------  --------------  --------  ------------  ------------  -----------------
Cardiovascular    In-practice           57        41,585         16.91               1.90
 disease
                  Referral             808       719,685          8.91
Endocrinology     In-practice            6         7,939         10.20               1.85
                  Referral             339       191,017          5.51
Family practice   In-practice           73        96,069         15.89               1.47
                  Referral           1,837     1,793,614         10.79
Gastroenterology  In-practice           34        21,337         68.89               1.81
                  Referral             315       176,714         38.16
General practice  In-practice          108       111,972         16.59               1.96
                  Referral           2,037     1,736,977          8.48
General surgery   In-practice           29        18,818         23.06               0.96
                  Referral           1,030       327,907         23.96
Internal          In-practice          187       206,001         21.26               1.76
 medicine
                  Referral           2,653     2,724,280         12.10
Maxillofacial     In-practice           12        18,033         15.25               2.42
 surgery
                  Referral             278       311,672          6.30
Nephrology        In-practice            6         5,688         43.42               4.04
                  Referral             119        69,391         10.74
Neurological      In-practice            6         1,335         40.45               1.91
 surgery
                  Referral             166        31,098         21.19
Neurology         In-practice           15         7,969         17.82               5.33
                  Referral             378       187,030          3.34
Neuropsychiatry   In-practice            8        14,379         19.33               5.45
                  Referral             118       197,712          3.55
Oral surgery      In-practice           57         3,423        255.92              20.06
                  Referral              26           392         12.76
Orthopedic        In-practice           50        29,409         16.12               3.24
 surgery
                  Referral             844       393,957          4.98
Preventive        In-practice            9        14,291         18.82               2.29
 medicine
                  Referral             115       112,640          8.23
Pulmonary         In-practice           19        20,076         18.23               2.39
 disease
                  Referral             248       192,183          7.63
Thoracic surgery  In-practice            4         1,300        209.23               6.66
                  Referral             136        24,330         31.40
Urology           In-practice           93        80,051         73.58               1.45
                  Referral             432       344,099         50.76
All listed        In-practice          773       699,675            --             1.92\b
 specialties
                  Referral          11,879     9,534,698            --
-----------------------------------------------------------------------------------------
\a This table excludes specialties where (1) physicians in one or
both of the comparison groups within the specialty did not order any
complex X rays, (2) the number of complex X rays ordered by the
physicians in the specialty accounted for less than 0.5 percent of
the total complex X rays used in our analyses, or (3) fewer than 10
physicians in that specialty ordered complex X rays.  The specialties
included in this table accounted for 97 percent of the complex X rays
used in our analyses. 

\b The ratio for all specialties combined is weighted by the number
of complex X rays ordered by physicians in each specialty. 

                                       Table III.8
                         
                          Simple X ray In-practice and Referral
                                          Rates

                                    Number                    Simple X
                                        of     Number of      rays per       Ratio of in-
Physician         Imaging         physicia        office  1,000 office       practice-to-
specialty\a       pattern               ns        visits        visits     referral rates
----------------  --------------  --------  ------------  ------------  -----------------
Cardiovascular    In-practice          311       355,080        185.90               2.69
 disease
                  Referral             554       406,190         69.19
Endocrinology     In-practice           29        19,804        214.25               0.95
                  Referral             316       179,152        225.24
Family practice   In-practice          740       749,314        158.10               1.59
                  Referral           1,170     1,140,369         99.34
Gastroenterology  In-practice           72        52,332        206.36               3.31
                  Referral             277       145,719         62.31
General practice  In-practice          643       588,605        187.69               1.82
                  Referral           1,502     1,260,344        102.93
General surgery   In-practice           98        63,028        165.23               1.39
                  Referral             961       283,697        118.64
Internal          In-practice        1,053     1,256,899        192.98               1.97
 medicine
                  Referral           1,787     1,673,382         97.99
Maxillofacial     In-practice           59        83,714        175.38               1.77
 surgery
                  Referral             231       245,991         99.02
Nephrology        In-practice           18        19,469        200.78               2.15
                  Referral             107        55,610         93.18
Neurology         In-practice           32        18,192         79.27               2.06
                  Referral             361       176,807         38.44
Neuropsychiatry   In-practice           74       139,340        255.59               2.23
                  Referral              52        72,751        114.75
Obstetrics/       In-practice           96        21,986        201.58               1.67
 gynecology
                  Referral             975       127,275        120.46
Ophthalmology     In-practice           19        30,507         27.93               2.81
                  Referral             794     1,414,767          9.92
Orthopedic        In-practice          810       403,701        567.81               1.86
 surgery
                  Referral              84        19,665        305.21
Otolaryngology    In-practice           91        79,145        102.95               2.88
                  Referral             266       205,317         35.78
Podiatry          In-practice          545       760,575        100.81               6.04
                  Referral              76        91,560         16.68
Preventive        In-practice           28        39,881        187.36               3.08
 medicine
                  Referral              96        87,050         60.92
Pulmonary         In-practice          121        98,608        224.02               1.55
 disease
                  Referral             146       113,651        144.64
Urology           In-practice           58        44,267         82.27               1.74
                  Referral             467       379,883         47.39
All listed        In-practice        4,897     4,824,447            --             2.10\b
 specialties
                  Referral          10,222     8,079,180            --
-----------------------------------------------------------------------------------------
\a This table excludes specialties where (1) physicians in one or
both of the comparison groups within the specialty did not order any
simple X rays, (2) the number of simple X rays ordered by the
physicians in the specialty accounted for less than 0.5 percent of
the total simple X rays used in our analyses, or (3) fewer than 10
physicians in that specialty ordered simple X rays.  The specialties
included in this table accounted for 96 percent of the simple X rays
used in our analyses. 

\b The ratio for all specialties combined is weighted by the number
of simple X rays ordered by physicians in each specialty. 

(See figure in printed edition.)APPENDIX IV
COMMENTS FROM THE DEPARTMENT OF
HEALTH AND HUMAN SERVICES
========================================================= Appendix III

(See figure in printed edition.)

(See figure in printed edition.)

MAJOR CONTRIBUTORS TO THIS REPORT
=========================================================== Appendix V

Edwin P.  Stropko, Assistant Director, (202) 512-7108
William M.  Reis, Evaluator-in-Charge
Mary E.  Fleischman
Herman A.T.  Jenich
Lyle H.  Lanier, Jr.
Suzanne C.  Rubins
Vanessa R.  Taylor
Sibyl L.  Tilson


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