Department of Health and Human Services 
OFFICE OF 
INSPECTOR GENERAL 
Medicare Payments for the Same Service 
by More Than One Carrier 
MARCH 2001 
OEI-03-00-00090  OFFICE OF INSPECTOR GENERAL 
The mission of the Office of Inspector General (OIG), as mandated by Public Law 95-452, is to 
protect the integrity of the Department of Health and Human Services programs as well as the 
health and welfare of beneficiaries served by them.  This statutory mission is carried out through a 
nationwide program of audits, investigations, inspections, sanctions, and fraud alerts.  The 
Inspector General informs the Secretary of program and management problems and recommends 
legislative, regulatory, and operational approaches to correct them. 
Office of Evaluation and Inspections 
The Office of Evaluation and Inspections (OEI) is one of several components of the Office of 
Inspector General.  It conducts short-term management and program evaluations (called 
inspections) that focus on issues of concern to the Department, the Congress, and the public.  The 
inspection reports provide findings and recommendations on the efficiency, vulnerability, and 
effectiveness of departmental programs. 
OEI's Philadelphia Regional Office prepared this report under the direction of Robert A. Vito, 
Regional Inspector General, and Linda M. Ragone, Deputy Regional Inspector General.  Principal 
OEI staff included: 
REGION  HEADQUARTERS 
Robert Katz, Project Leader  Tricia Davis, Program Specialist 
Erika Q. Lang, Program Analyst 
To obtain copies of this report, please call the Philadelphia Regional Office at (800) 531-9562. 
Reports are also available on the World Wide Web at our home page address: 
http://www.dhhs.gov/progorg/oei  E X E C U T I V E   S U M M A R Y  
PURPOSE 
To determine if multiple carriers paid for duplicate Part B services rendered by the same 
provider. 
BACKGROUND 
The Health Care Financing Administration (HCFA) contracts with private health insurance 
companies called carriers to process Part B claims for reimbursement.  After furnishing a 
physician service, providers submit a claim for reimbursement to the carrier with 
jurisdiction over this service.  Under the Common Working File system, the carrier then 
sends the claims information to one of nine host sites for approval.  At the host site, the 
claim is screened for consistency, entitlement, and duplication of previously processed 
claims. 
Potentially duplicate claims are ones which contain identical elements for a service.  Both 
the carriers and the Common Working File host sites are required to review incoming 
claims for possible duplication using certain criteria, and to deny ones that are potentially 
duplicate. 
For this inspection, we selected a sample of potential duplicate services from HCFAs 5 
percent National Claims History file for 1998.  We contacted carriers who had paid for the 
services in our sample, and asked them to identify the providers who had billed for these 
services.  We then asked providers to furnish us with medical documentation to support 
the sample services.  Sample services represented 15 different procedure codes.  We also 
examined data from HCFAs 100 percent claims file for the providers who rendered 
services in our sample. 
FINDINGS 
Medicares claims processing system did not prevent any of the duplicate 
payments in our sample 
None of the medical records received from providers in our sample justified billings to 
multiple carriers.  Although carriers and Common Working File host sites have checks 
designed to detect duplicate billings, these measures are clearly vulnerable to duplicate 
claims that are sent to different carriers. 
i 
Medicare Payments for the Same Service  OEI-03-00-00090  Some sample providers had a significant number of potential duplicate billings 
In reviewing 100 percent of the providers billings for the 15 procedure codes reviewed, 
we found that nearly one-fourth of the providers in our sample (20 of 86) had at least 20 
services involving potential duplicate billings.  Seven providers had more than 100 services 
involving potential duplicate billings in 1998.  Further, the duplicate billings were not 
limited to the 15 codes.  We found other duplicate billings representing additional services, 
including evaluation and management services, group psychotherapy, and magnetic 
resonance imaging. 
RECOMMENDATIONS 
We believe our findings highlight a significant vulnerability in Medicares claims processing 
system.  The inability to detect duplicate payments by multiple carriers could lead to substantial 
future losses for Medicare. 
To address the vulnerabilities identified in this report, we recommend that HCFA: 
Revise Common Working File edits to detect and deny duplicate billings to more 
than one carrier.  If this measure is determined not to be cost effective, then 
increased post-payment reviews should be conducted, particularly in areas where 
providers commonly perform services in multiple carrier jurisdictions. 
Promote provider compliance and cooperation with the Office of Inspector 
Generals Compliance Program Guidance for Individual and Small Group Physician 
Practices.  Providers in solo or small group physician offices should be encouraged to 
conduct effective voluntary compliance activities to maintain optimum levels of integrity in 
their practices. 
Encourage providers to clarify carrier jurisdiction questions, in addition to other 
billing questions, by using toll-free telephone lines recently established by carriers. 
We have forwarded claims information to HCFA so they may take appropriate action regarding 
the duplicate payments cited in this report.  In addition, we have referred some of the providers 
that we identified as having high numbers of duplicate billings to our Office of Investigations. 
AGENCY COMMENTS 
The HCFA concurred with our recommendations.  The HCFA stated that they will 
reexamine existing criteria regarding duplicate editing in the Common Working File 
system to determine the cost effectiveness of including the carrier number in the match 
ii 
Medicare Payments for the Same Service  OEI-03-00-00090  criteria.  If a revision is determined not to be cost effective, improved duplicate billing 
edits will be considered within the Common Working File redesign initiative.  The HCFA 
also plans to prepare a model article for inclusion in all Medicare contractor carrier 
bulletins, reminding providers to conduct effective voluntary compliance activities to 
ensure high levels of integrity in their practices.  To encourage providers to clarify carrier 
jurisdiction questions via the carrier toll-free telephone lines, HCFA will instruct carriers 
to alert personnel servicing the toll-free lines to be sensitive to this issue and to provide 
appropriate information to providers. 
iii 
Medicare Payments for the Same Service  OEI-03-00-00090  T A B L E  O F  C O N T E N T S  
PAGE

EXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  i

INTRODUCTION  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

FINDINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Claims processing system did not prevent duplicate payments . . . . . . . . . . . . . . . . . . . . .  6

Some providers had significant numbers of potential duplicate billings  . . . . . . . . . . . . . .  7

RECOMMENDATIONS  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  9

APPENDICES

A: Procedure Codes Included in Sample . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  10

B: Estimate and Confidence Interval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  11

C: Agency Comments  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

iivv 
Medicare Payments for the Same Service  OEI-03-00-00090  I N T R O D U C T I O N  
PURPOSE 
To determine if multiple carriers paid for duplicate Part B services rendered by the same 
provider. 1 
BACKGROUND 
The Health Care Financing Administration (HCFA), which administers the Medicare 
program, contracts with private health insurance companies called carriers to process 
Part B claims for payment.  Claims under Medicare Part B include medical and surgical 
services by physicians, ambulance services, durable medical equipment, outpatient 
hospital services, and laboratory services. 
Carrier Jurisdiction 
After physician services are furnished to a Medicare beneficiary, the provider submits a 
claim for reimbursement to the carrier with jurisdiction over the service.  In accordance 
with the Omnibus Reconciliation Act of 1989, as amended by the Omnibus Reconciliation 
Act of 1990, carrier jurisdiction for physician services was revised to reflect the locality 
where the service was furnished.  Previously, carrier jurisdiction was based on the 
location of the physicians office.  The rule governing carrier jurisdiction has been in 
effect since January 1, 1992; however, carriers were allowed to delay its implementation 
until July 1, 1998. 
Processing Part B Claims 
A carrier receives claims via electronic submission or mail.  The carrier enters the claim 
into its processing system, calculates the payment amount, and conducts consistency and 
utilization checks using computerized edits.  The carrier then sends the claim to one of 
nine host sites of the Common Working File (CWF) system.  The HCFA established the 
Common Working File system in 1991 to improve the accuracy of claims processing. 
The host sites maintain beneficiary claims history and entitlement information.  Each 
beneficiary is assigned to only one host site.  At the host site, the claim is screened for 
consistency, entitlement, and duplication of previously processed claims.  This screening 
process is Medicares front line of defense against paying inappropriate claims.  Within 
1 The term provider, as used in this report, refers to any practitioner who provides a Part B service to a 
Medicare beneficiary. 
1 
Medicare Payments for the Same Service  OEI-03-00-00090  24 hours of receiving a claim, the host site makes one of three payment determinations: 
(1) pay the claim, (2) reject the claim, or (3) hold the claim to obtain missing information. 
Detecting Duplicate Payments 
As part of Medicares guidelines to detect and prevent inappropriate payments, both the 
Common Working File system and the carriers are required to conduct checks on claims 
to detect duplicate payments.  The Common Working File host sites check for exact 
duplicate claims by comparing the carrier number, the claims document control number, 
and service dates on the Files history record.  If these fields are identical on two claims, 
one claim is denied.  According to procedures described in the Medicare Carriers Manual 
regarding the control of potentially duplicate payments, as well as information obtained 
from HCFA, carriers are required to deny claims that match on certain fields 
(beneficiarys health insurance claim number, identical service dates, provider number, 
type of service, procedure code, place of service, and submitted charge).  As a further 
check for duplicate services, service dates are matched with one or more of the following 
variables: provider number, type of service, and procedure code.  If these items match, 
the claim is held for review and duplicate payments are denied.  Line items within claims 
are also compared for duplicate entries. 
METHODOLOGY 
To determine if multiple carriers appropriately paid for what appeared to be duplicate 
services, we obtained and reviewed medical documentation from a sample of providers to 
see if it justified the services. 
Sampling 
We examined 1998 Part B paid services for a 5 percent sample of Medicare beneficiaries 
in the National Claims History file.  This 5 percent file, which contained adjustments 
through June 1999, was 98 percent complete.  We used six criteria to determine if two 
services appeared to be duplicate: the beneficiarys health insurance claim number; the 
Unique Physician Identification Number of the provider performing the service; the start 
date of service; HCFAs Common Procedure Coding System code describing the service; 
and the two modifiers that can further describe the service.  If the six criteria for two 
services were identical, we considered those services to be potential duplicates.  From 
this pool of potentially duplicate services, we selected those that had been billed to more 
than one carrier.  As a result of this effort, we identified a universe of 5,876 services. 
2 
Medicare Payments for the Same Service  OEI-03-00-00090  From the 5,876 services, we identified 40 procedure codes with the highest allowed 
payment amounts in 1998.  With the assistance of a carriers medical staff, we arrayed the 
codes into three categories: (1) services that should only be billed once per day by a 
single provider, (2) services that should rarely be billed more than once per day, and (3) 
services which could commonly be billed more than once per day.  We narrowed our 
sample of procedure codes to include 15 from the first two categories.  In our selection, 
we attempted to include a wide variety of service codes representing diverse provider 
specialties in various places of service. We then selected a random sample of services 
from each of the 15 codes. 
We divided the 15 codes into three tiers based on number of potential duplicate services. 
The first tier had 14 or fewer duplicate services.  The second tier had 16-34, and the third 
tier had more than 34 services.  For more information, see Appendix A.  From each 
procedure code in the first tier, we chose a maximum of eight services.  From each code 
in the second and third tiers, we selected a maximum of 14 and 30 services respectively. 
At this stage of sample selection, we had a total of 250 services conducted by 89 
providers.  We subsequently eliminated services from three providers who were either 
under investigation by the Inspector Generals Office of Investigations (six services), or 
whose Unique Physician Identification Number was not accurately reflected on the 
National Claims History file (two services).  Our resulting sample included 242 total 
services by 86 different providers.  Pending receipt of documentation from providers, we 
presumed these 242 services actually represented 121 legitimate services which had been 
appropriately billed to the correct carrier, and 121 duplicate services which somehow had 
been billed to, and paid by, an additional carrier. 
Data Collection 
Carrier requests.  We contacted each carrier that had paid for a service in our sample. 
We requested that carriers identify the names and addresses, including both the location 
and billing address, of the providers who submitted claims for our sample services.  As 
each duplicate service in our sample was billed to multiple carriers, we typically requested 
each providers name and address information from two carriers.  In response, we often 
received two different addresses for each provider.  In addition, we asked carriers to 
confirm the Unique Physician Identification Number of the providers identified in the 
National Claims History file as having rendered the services.  We also asked the carriers 
for copies of the claims that contained our sample services. 
Provider requests.  We contacted providers using two methods: by mail or through an 
on-site visit. 
Our primary method of contacting providers was via letters, asking them to furnish us 
with medical documentation to support the services in our sample.  We sent a form with 
each letter which detailed key elements of each service, including the name of the carrier 
that was billed. 
3 
Medicare Payments for the Same Service  OEI-03-00-00090  As mentioned above, we often had two addresses for each provider, one from each 
carrier.  If the two carriers gave us the same address, we sent two forms, each 
representing one service, to that address.  If the two carriers provided us with different 
addresses, we sent a separate form to each address.  Primarily, we mailed the letters to 
the location addresses provided by the carriers.  In the absence of a location address, we 
used billing addresses.  We sent 121 letters to 82 providers, and visited 4 providers to 
obtain the medical documentation in person. 
If a provider returned two forms along with medical documentation, we considered the 
response complete.  However, if the provider returned only one form for one carrier 
along with documentation, we contacted the provider to determine if a different set of 
records was available for the service billed to the other carrier.  We telephoned providers 
if they failed to respond by the due dates contained in the letters. 
Several providers did not submit documentation even after repeated follow-up telephone 
calls.  In these instances, we sent the provider a letter stating we would conclude the 
provider did not have the documentation if we didnt receive it by a certain date.  We did 
not hear back from five providers.  Therefore, we counted them as not having 
documentation. 
When making follow-up contacts for medical documentation, we were careful to point 
out that two carriers had paid for the billed services, and that the provider should send us 
documentation to support each service billed.  We also asked providers or their office 
personnel to explain why duplicate billings had been submitted to more than one carrier. 
Of the 86 providers in our sample, 79 sent medical documentation, representing 222 
services.  Five providers, representing 12 services, did not send any medical 
documentation.  Two providers, representing 8 services, could not be located. 
Consequently, there were 234 services for which we received or attempted to obtain 
documentation. 
Additional data provided by HCFA.  As stated above, our sample of 242 total services 
involving 86 providers was pulled from a 5 percent sample of Medicare beneficiaries in 
the National Claims History file.  In order to learn more about their billing practices, we 
asked HCFA to provide us with data for our sample providers from the 100 percent 
claims file.  This file contains claims information for all Medicare beneficiaries. 
Furthermore, this file was more current than the 5 percent claims file, as it included any 
adjustments in services made through June 2000. 
Data Analysis 
Medical documentation from providers.  We reviewed medical documentation from 
providers to determine if the services should have been billed to two carriers.  We did not 
review the documentation to determine medical necessity.  We determined that the 
4 
Medicare Payments for the Same Service  OEI-03-00-00090  potential duplicate billing would be justified if there were medical documentation to 
support each service billed.  For example, in the case of an inpatient hospital visit, the 
medical documentation sent to us should have verified, at a minimum, medical care by the 
same provider for the same patient on the same day in two hospitals located in different 
carrier jurisdictions.  If documentation supported one service only, we determined that 
one of the claims was a duplicate, and should not have been paid. 
We computed overpayment amounts for the services in our sample.  If documentation 
was submitted to support only one billing, we attributed the correct payment to the 
carrier where the service was rendered.  If we were unable to ascertain which carrier had 
jurisdiction for the service performed based on the medical records sent to us, we 
attributed the correct payment to the carrier with the higher allowed amount (thereby, 
resulting in a lower and more conservative improper payment amount).  If the allowed 
amounts were the same, we attributed payment to the carrier listed first in our database. 
Provider billing histories.  We examined the 100 percent National Claims History file 
for Part B paid services for all beneficiaries seen by the providers in our sample.  We 
identified all Part B services billed by our sample providers in 1998.  Using six criteria 
(described on page 2), we identified the total number of potential duplicate services billed 
by sample providers.  We analyzed duplicate billings for the 15 procedure codes in our 
sample, as well as all other procedure codes.  We also calculated the allowed amounts for 
these services. 
As the 100 percent National Claims History file contained more current data than the 5 
percent file, we analyzed it to determine if any adjustments to our sample services had 
been made.  We found that 16 services in our sample were eliminated from the more 
current data in the 100 percent claims file.  The dropped services may signify that the 
carrier, provider, or other party discovered the duplicate billing and the provider refunded 
the overpayment to Medicare.  These services, representing seven providers, were 
retained in our sample since we obtained the 100 percent claims file after collecting 
medical documentation from providers. 
__________ 
This study was conducted in accordance with the Quality Standards for Inspections 
issued by the Presidents Council on Integrity and Efficiency. 
5 
Medicare Payments for the Same Service  OEI-03-00-00090  F I N D I N G S  
Medicares claims processing system did not prevent any of 
the duplicate payments in our sample 
None of the medical records received from providers in our sample justified billings to 
multiple carriers.  For 222 services, provider documentation did not support the need for 
billing two separate carriers.  Therefore, half of these services (111) were improperly 
submitted to and paid by a Medicare carrier.  There were an additional 12 services for 
which no documentation was provided.  Medicare allowances for the 123 improper 
services totaled almost $12,000.  We estimate total improper allowances for the 15 codes 
as approximately $446,000.  See Appendix B for estimate and confidence interval. 
Although carriers and Common Working File host sites have checks designed to detect 
duplicate billings, these measures are clearly vulnerable to duplicate claims sent to 
different carriers. Carrier edits are designed to detect duplicates within a carrier, rather 
than across carriers.  Carriers, therefore, cannot compare their incoming claims with 
those received by neighboring carriers.  The only time that duplicate claims submitted to 
multiple carriers could be identified is when the data is sent to the host sites for 
processing.  For the services in our sample, however, it appears that the Common 
Working File system did not identify duplicate services billed to more than one carrier. 
Few providers reported making refunds to Medicare 
Only eight providers stated that they had refunded overpayments to the appropriate 
carrier.  Seven of these providers initiated the refunds as a result of our inquiries.  These 
refunds totaled approximately $1,100 and included not only the services in our sample, 
but other duplicate payments which the provider discovered following our inquiries.  An 
additional four providers, who acknowledged their errors, asked for instructions on how 
they should refund their excessive payments to the appropriate carrier. 
Providers gave various reasons to explain duplicate billings 
Fifteen providers told us that, prior to our requests, they were totally ignorant of the 
existence of the duplicate billings and had no idea how they had occurred.  Another seven 
providers cited the policy change, which based carrier jurisdiction on where the service 
was performed rather than the location of the providers office, as the reason for their 
duplicate billings.  Although this policy was effective in 1992, carriers were allowed to 
delay implementation until July 1998.  One New York City provider explained in a letter, 
I learned from a billing seminar . . . that claims for patient services received in Queens . . 
. are processed by GHI [Group Health Incorporated].  After 
6 
Medicare Payments for the Same Service  OEI-03-00-00090  learning this, I reapplied for reimbursement to GHI . . . and assumed that I would not be 
paid by Empire.  However  . . . both Empire and GHI sent reimbursements to my 
office.  Other explanations cited by providers included confusion caused by carrier 
transitions, having offices or performing services across State lines, and inadvertent 
errors by billing services. 
Some sample providers had a significant number of 
potential duplicate billings 
In reviewing 100 percent of the providers billings for the 15 procedure codes, we found 
that nearly one-fourth of the sample providers (20 of 86) had at least 20 services 
involving potential duplicate billings to multiple carriers.  One of the 20 providers had 
966 potential duplicate services, with questionable allowances totaling about $31,000. 
Another six of the 20 providers had at least 100 services involving potential duplicate 
billings.  The 86 sample providers had a total of 2,871 services representing 
approximately $101,000 in improper allowances due to questionable billings to multiple 
carriers. 
For some sample providers, potential duplicate services comprised a high percentage of 
overall services for the 15 codes reviewed.  As shown in Table 1, potential duplicate 
services represented one-fifth or more of the total services paid by Medicare to several 
providers.  Specifically, there were 5 providers whose potential duplicate services 
represented 20 percent or more of their overall billings.  For 8 of the 86 providers, at 
least 10 percent of their total 1998 Medicare billings involved potential duplicate 
services.  In contrast, for more than two-thirds of the 86 providers, potential duplicate 
billings represented less than 1 percent of their total Medicare claims. 
Table 1.  Percentage of Services Involving Potential Duplicates for 15 Sample Codes 
Number of services  Total number of  Percentage of services 
Provider  involving duplication  services overall  involving duplication 
A  334  828  40% 
B  966  2748  35% 
C  114  332  34% 
D  38  124  31% 
E  115  565  20% 
A detailed review of all procedure codes showed that duplicate billings to multiple 
carriers were not limited to the 15 codes in our sample.  For the 86 providers, an 
additional 1,667 services involved potential duplicate billings, representing nearly 
$86,000 in improper allowances.  Fourteen of the top 25 codes that appeared most 
frequently were evaluation and management codes used for physician services.  Many of 
these codes can be billed only once per day, and, therefore, any duplication would seem 
questionable.  Other procedure codes involved in the duplicate billings were group 
7 
Medicare Payments for the Same Service  OEI-03-00-00090  psychotherapy (90853), subsequent nursing facility care per day (99312), end stage renal 
disease related services per day (90925), and spinal canal magnetic resonance imaging 
(72148).  The definitions for these codes suggest that a provider would rarely furnish a 
beneficiary with two of these services on the same day, especially in two different carrier 
jurisdictions. 
8 
Medicare Payments for the Same Service  OEI-03-00-00090  R E C O M M E N D A T I O N S  
We believe our findings highlight a significant vulnerability in Medicares claims processing 
system.  The inability to detect duplicate payments by multiple carriers could lead to substantial 
future losses for Medicare. 
To address the vulnerabilities identified in this report, we recommend that 
HCFA: 
Revise Common Working File edits to detect and deny duplicate billings to more 
than one carrier.  If this measure is determined not to be cost effective, then 
increased post-payment reviews should be conducted, particularly in areas where 
providers commonly perform services in multiple carrier jurisdictions. 
Promote provider compliance and cooperation with the Office of Inspector 
Generals Compliance Program Guidance for Individual and Small Group Physician 
Practices.  Providers in solo or small group physician offices should be encouraged to 
conduct effective voluntary compliance activities to maintain optimum levels of integrity 
in their practices. 
Encourage providers to clarify carrier jurisdiction questions, in addition to other 
billing questions, by using toll-free telephone lines recently established by carriers. 
We have forwarded claims information to HCFA so they may take appropriate action regarding 
the duplicate payments cited in this report.  In addition, we have referred some of the providers 
that we identified as having high numbers of duplicate billings to our Office of Investigations. 
AGENCY COMMENTS 
The HCFA concurred with our recommendations.  The HCFA stated that they will 
reexamine existing criteria regarding duplicate editing in the Common Working File 
system to determine the cost effectiveness of including the carrier number in the match 
criteria.  If a revision is determined not to be cost effective, improved duplicate billing 
edits will be considered within the Common Working File redesign initiative.  The HCFA 
also plans to prepare a model article for inclusion in all Medicare contractor carrier 
bulletins, reminding providers to conduct effective voluntary compliance activities to 
ensure high levels of integrity in their practices.  To encourage providers to clarify carrier 
jurisdiction questions via the carrier toll-free telephone lines, HCFA will instruct carriers 
to alert personnel servicing the toll-free lines to be sensitive to this issue and to provide 
appropriate information to providers. 
9 
Medicare Payments for the Same Service  OEI-03-00-00090   A P P E N D I X  A  
Procedure Codes Included in Sample

Number of Potential Duplicate  Number of Services 
Procedure Code  Services in Universe  Selected for Sample 
70553  2  2 
72158  4  4 
Tier 1 
90921  8  8 
66984  12  8 
90801  14  8 
99223  16  14 
99204  20  14 
Tier 2 
99254  20  14 
99244  24  14 
11721  34  14 
90862  42  30 
99238*  42  24 
Tier 3 
90816  82  30 
99232*  110  28 
99213  226  30 
TOTAL  656  242 
*Six services from procedure code 99238 were dropped from the sample, as the provider was under investigation 
by the Inspector Generals Office of Investigations. Two services were dropped from procedure code 99232, as 
the providers Unique Physician Identification Number was not accurately reflected on the National Claims 
History file. 
10 
Medicare Payments for the Same Service  OEI-03-00-00090  A P P E N D I X B   
Estimate and Confidence Interval

We used the Survey Data Analysis (SUDAAN) software package to compute allowance and 
confidence interval estimates presented in the following table.  The estimate is weighted based on 
the sample design and is reported at the 95 percent confidence level. 
Weighted Total Estimate  95% Confidence Interval 
Questionable Medicare Allowances  $446,015  $367,775 - $524,255 
for 15 Sample Codes 
11 
Medicare Payments for the Same Service  OEI-03-00-00090  A P P E N D I X  C  
Health Care Financing Administration Comments

12 
Medicare Payments for the Same Service  OEI-03-00-00090  A P P E N D I X  C  
13 
Medicare Payments for the Same Service  OEI-03-00-00090  A P P E N D I X  C  
14 
Medicare Payments for the Same Service  OEI-03-00-00090