Physicians' Charges Under Medicare: Assignment Rates and Beneficiary Liability

Abstract

Under Medicare's Part B program, the physician decides whether to accept assignment of claims. When assignment is accepted, the physician agrees to accept as full payment Medicare's allowed charge. Physicians' acceptance of assignment is of considerable importance in relieving the beneficiaries of the burden of the costs of medical care services. This factor and the beneficiaries' liabilities for premiums, the annual deductible, and coinsurance are analyzed in considerable detail in this report.

Data from physicians' claims for services in 1975 show that 45.8 percent of the services and 47.2 percent of the charges were assigned for the aged. There were wide variations in the rate of acceptance of assignment by physician specialty, and by age, race, and residence of beneficiaries. Total beneficiary liability from the deductible, coinsurance, and from unassigned claims amounted to 37.7 percent of total physicians' charges due. When the premium which the beneficiary pays for Part B is included, beneficiary liability rises to 69.2 percent of total physicians' charges due.

Medicare's Part B program (Supplementary Medical Insurance) provides basic health insurance coverage to ease the financial burden of health care services for the aged population of the nation, for disabled Social Security beneficiaries, and for persons with end stage renal disease. Although the program was not intended to cover all the costs of medical care, several factors can diminish the protection beneficiaries have against the burden of large medical bills. These factors include the level of physicians' acceptance of assignment and the program's cost-sharing mechanisms.

This paper provides a detailed description of physicians' assignment rates for services rendered in 1975; assignment rates are analyzed by demographic characteristics of the beneficiaries, (that is, persons enrolled in Part B) by geographic area, and by physician specialty. This paper also analyzes total beneficiary outlays (for the premium, the deductible, coinsurance, and liability from unassigned claims) to determine the total burden on beneficiaries and compares that total with program reimbursements.

Assignment

Physicians' assignment decisions determine to a significant extent the degree to which beneficiaries are protected by Medicare's Part B insurance. Under the Medicare program, the physician decides whether to accept assignment on each Medicare claim. If the claim is assigned, the physician agrees to accept as full payment the amount Medicare determines as reasonable.¹ If the physician does not accept assignment, the Medicare patient is liable for the difference between the amount charged and the amount Medicare allows; if this difference is large, beneficiary liability can be substantial. In such instances, the program is less successful in protecting beneficiaries from the cost of health care.²

Beginning with 1968, national data are available on the rate of acceptance of assignment based on the total number of claims. In that year, the net assignment rate³ was 59.0 percent. In 1969, the proportion rose to 61.5 percent, the highest it has ever registered since data have been available. Thereafter, there was a general decline each year in the percent of assigned claims. Comparable data are also available beginning with 1971 on the percent of total charges that were assigned. As may be seen in the following data, the percentage of total charges assigned was lower each year than the percentage of claims assigned. The percent of charges assigned reached a low point in 1976 (47.6 percent), then rose in 1977 and again in 1978.

Year	Net Assignment Rate (Based on Claims)	Net Assignment Rate (Based on Charges)
1968	59.0	—
1969	61.5	—
1970	60.8	—
1971	58.5	53.8
1972	54.9	50.3
1973	52.7	48.1
1974	51.9	47.8
1975	51.8	47.7
1976	50.5	47.6
1977	50.5	48.2
1978	50.6	49.6

It should be noted that the data above—as well as the data generated for this study—include claims for Medicare beneficiaries who are also enrolled in Medicaid. For Medicaid beneficiaries, assignment is mandatory. Consequently, if the assignment rate were computed for voluntary assignment only, the rate would be lower.

Sources of Data

The detailed information that follows is derived from a new and continuing data set based on claims for physicians' services in 1975. The data are furnished centrally to HCFA from claims submitted on Medicare “1490” forms and processed by Medicare carriers for a 5 percent sample of Medicare beneficiaries throughout the nation. To facilitate data processing for this study, a subset was used consisting of a 1 percent sample of Medicare beneficiaries. This new data system was designed to provide a greater depth of information about the use of physicians' services than previously available from the ongoing payment record system. Data items available, beginning with 1975 services, include the Medicare identification number of the patient, the physician's total charge, the amount Medicare allowed, the Medicare reimbursement, whether or not the claim was assigned, the speciality of the physician, type of service (that is, medical care, surgery, laboratory service, etc.), and site of service (office, hospital, etc.). Data from the master health insurance enrollment file—which contains the age, sex, race, and residence of the beneficiary—are incorporated into the claims file data to provide information about the characteristics of the users.

Findings

Variations in Assignment by Age, Sex, and Race

Table 1 shows the percent of services assigned and the percent of charges assigned based on the new data set.

Table 1. Medicare Beneficiaries: Assignment Rates for Aged and Disabled Beneficiaries by Age, Sex, and Race, 1975.

	Aged		Disabled
Age, Sex, Race	Percent of Services Assigned	Percent of Total Charges Assigned	Percent of Services Assigned	Percent of Total Charges Assigned
Total	45.8	47.2	59.7	62.4
Age:
Under 25	—	—	77.1	86.2
25-44	—	—	73.3	76.4
45-64	—	—	56.7	58.5
65-69	42.0	44.1	—	—
70-74	43.3	45.0	—	—
75-79	46.2	47.5	—	—
80-84	48.3	49.4	—	—
85 +	56.8	57.7	—	—
Sex:
Male	45.5	47.0	61.0	63.5
Female	45.9	47.3	58.1	61.0
Race:
White	43.4	45.0	56.1	58.8
All other Races	78.4	79.3	84.5	87.0

The Aged

Among the aged, 45.8 percent of all physicians' services and 47.2 percent of all physicians' charges were assigned. Physicians' acceptance of assignment for services of males versus females showed little difference (45.5 percent and 45.9 percent of services respectively). It is notable that acceptance of assignment was greater with successively older age groups of beneficiaries—42.0 percent of services in the group 65-69 years of age compared to 56.8 percent for persons aged 85 and over. These findings may reflect several factors, including increased willingness on the part of physicians to accept assignment for steady, long-time patients, or for patients who are likely to have diminished income and assets. Also, as age increases there is increased participation in Medicaid—for which there is mandatory assignment.

Services for non-white beneficiaries were assigned at a considerably higher rate than services for white beneficiaries. For non-white beneficiaries 78.4 percent of services were assigned in contrast to 43.4 percent of services for white beneficiaries. Socioeconomic factors (such as poverty or physician behavior toward non-white beneficiaries) may influence the racial variation, but required assignment for Medicare beneficiaries who are also State Medicaid beneficiaries very likely explains much of the difference.⁴

The Disabled

Among the disabled, physicians accepted assignment for 59.7 percent of the services provided—a proportion considerably higher than that for the aged. Unlike the aged, assignment of services for the disabled was lower for successively older age groups—77.1 percent for persons under 25 years of age to 56.7 percent for those in the age group 45-64 years. Similar to the aged, the sex of the disabled was not a determining factor. Also similar to the findings on the aged, data on non-whites showed a much higher assignment rate than data on whites—84.5 percent versus 56.1 percent of services respectively. This difference again is very likely explained by the levels of Medicaid entitlement.

Assignment by Geographic Area

Table 2 shows assignment rates by census region, division, and State.⁵ Among the census regions, acceptance of assignment for services to the aged ranged from a low in the North Central region of 35.2 percent to a high of 56.8 percent in the Northeast region. Among the census divisions, the lowest percentages of services assigned were in the West North Central (32.4), Mountain (35.8), and East North Central (36.7) divisions while the highest rate was in the New England division (66.3). Similar variations were seen for the disabled population except that the rates for the disabled were consistently higher than those for the aged in all areas, possibly reflecting physicians' perceptions of less favorable economic conditions of the disabled compared with the aged.

Table 2. Medicare Beneficiaries: Assignment Rates for Aged and Disabled Beneficiaries, by State, 1975.

	Aged		Disabled
Area of Residence	Percent of Services Assigned	Percent of Charges Assigned	Percent of Services Assigned	Percent of Charges Assigned
United States	45.8	47.2	59.7	62.4
Northeast	56.8	59.9	70.3	74.2
New England	66.3	64.6	79.1	79.7
Maine	78.2	72.5	82.5	91.3
New Hampshire	58.0	52.3	73.4	74.4
Vermont	68.8	70.6	96.5	96.4
Massachusetts	76.3	77.4	84.2	83.4
Rhode Island	80.6	81.6	86.8	89.7
Connecticut	31.2	31.2	51.7	52.9
Middle Atlantic	53.8	58.6	68.2	73.0
New York	54.9	57.7	67.9	67.4
New Jersey	46.2	52.3	63.4	72.6
Pennsylvania	56.9	65.1	72.1	82.0
North Central	35.2	36.7	55.0	57.5
East North Central	36.7	38.6	56.6	59.1
Ohio	27.3	26.6	48.7	52.2
Indiana	27.6	25.0	38.5	35.1
Illinois	31.5	32.2	52.9	57.9
Michigan	65.8	66.0	74.7	78.2
Wisconsin	43.6	35.6	70.3	54.6
West North Central	32.4	32.8	50.6	52.6
Minnesota	32.3	29.5	54.9	60.5
Iowa	28.8	25.8	53.1	46.9
Missouri	29.7	31.8	47.4	49.5
North Dakota	36.9	33.2	43.7	33.7
South Dakota	24.2	19.8	20.5	40.5
Nebraska	26.5	29.6	63.7	68.4
Kansas	50.8	52.4	50.3	50.7
South	47.6	46.1	58.9	59.2
South Atlantic	42.8	43.8	58.5	60.1
Delaware	62.0	62.1	89.7	71.6
Maryland	54.1	57.2	65.5	72.3
District of Columbia	58.6	68.8	78.8	78.8
Virginia	48.2	49.4	67.6	67.1
West Virginia	45.7	47.5	62.4	73.4
North Carolina	45.7	46.7	54.2	50.9
South Carolina	59.2	61.1	65.4	66.6
Georgia	53.6	53.2	59.5	60.2
Florida	32.4	34.5	49.0	53.6
East South Central	52.9	50.6	59.9	58.5
Kentucky	38.0	37.8	44.0	36.7
Tennesse	43.7	43.3	57.8	56.5
Alabama	59.7	60.1	64.7	68.6
Mississippi	70.1	62.7	68.7	66.6
West South Central	51.4	48.0	58.6	58.1
Arkansas	57.5	52.2	59.1	66.9
Louisiana	39.1	33.1	46.1	45.7
Oklahoma	32.6	31.2	33.1	41.4
Texas	56.7	54.2	66.4	63.1
West	1	1	1	1
Mountain	35.8	37.4	48.0	53.3
Montana	22.5	22.6	11.7	20.0
Idaho	21.5	26.3	65.3	53.8
Wyoming	27.5	30.8	52.1	31.0
Colorado	50.3	48.8	61.1	65.8
New Mexico	45.1	47.7	51.4	60.9
Arizona	27.1	27.8	27.7	35.0
Utah	35.3	41.0	50.2	33.2
Nevada	42.6	47.5	71.1	80.3
Pacific	1	1	1	1
Washington	34.5	34.2	54.4	55.6
Oregon	18.0	19.9	37.5	36.3
California	1	1	1	1
Alaska	34.0	38.2	28.4	25.3
Hawaii	39.1	38.5	74.6	69.5

¹Codes submitted for this data base to indicate whether claims were assigned are unreliable for California. Because California's assignment rate significantly affects the rate for the census division and region, data on assignment rates are also omitted for the Pacific division and the Western region. Workload reports generated by the Bureau of Program Operations, HCFA, indicate that 57.6 percent of total claims (aged and disabled combined) and 48.4 percent of total charges processed by California fiscal agents (carriers) in 1975 were assigned.

There were wide variations in assignment rates among the States, with the figures for the aged ranging from a low of 18.0 percent of services assigned in Oregon to a high of 80.6 percent in Rhode Island. No geographic pattern in rate of assignment was apparent. In fact, adjacent States often had greatly different rates: Pennsylvania—56.9 percent and Ohio—27.3 percent; Connecticut—31.2 percent and Rhode Island—80.6 percent.

It may be noted that in most areas the percent of charges assigned was a little higher than the percent of services assigned, indicating that the average charge for assigned services was generally a little higher than the average charge for unassigned services.

These State data also show the same pattern of higher assignment rates for the disabled compared to the aged with the figures for the disabled ranging from a low of 11.7 percent of services assigned in Montana to a high of 96.5 percent in Vermont.

Assignment by Physician Specialty

Table 3 shows the rate of assignment of services and charges according to the specialties of the physicians. Assignment rates varied considerably among the physician specialties. For the aged, the percentages of services assigned ranged from 32.0 percent for services by licensed chiropractors to 67.1 percent for services by pathologists. For the disabled, the percentages ranged from 39.8 percent for otology/rhinology/laryngology services to 72.0 percent for podiatrists' services. Figure 1 shows the percents of total charges assigned for the five types of physicians that serve the greatest number of beneficiaries. Of these five types of physicians, acceptance of assignment for the aged was highest for Radiologists (55.5) and lowest for Ophthalmologists (44.0). The figure also shows that for each specialty except ophthalmology, the rate of assigned charges for the disabled is approximately 15 percentage points higher than for the aged.

Table 3. Medicare Beneficiaries: Assignment Rates for Aged and Disabled Beneficiaries by Physician Specialty, 1975.

	Aged		Disabled
Physician Specialty	Percent of Services Assigned	Percent of Total Charges Assigned	Percent of Services Assigned	Percent of Total Charges Assigned
All Physicians	45.8	47.2	59.7	62.4
General Practice	46.7	49.0	59.9	62.3
Family Practice	48.6	51.4	60.6	64.1
Internal Medicine	44.1	48.3	57.2	64.2
Cardiovascular Disease	47.3	50.9	57.1	60.2
Dermatology	44.3	49.5	44.7	53.6
General Surgery	49.9	55.3	64.2	70.2
Otology/Rhinology/Laryngology	35.4	43.2	39.8	50.9
Ophthalmology	35.3	44.0	45.1	39.7
Orthopedic Surgery	46.0	52.8	52.0	56.0
Urology	45.7	50.5	55.2	62.9
Anesthesiology	52.5	51.4	63.8	63.4
Pathology	67.1	62.3	71.7	73.7
Radiology	59.0	55.5	70.0	68.8
Chiropractor, Licensed	32.0	34.7	47.5	48.6
Podiatry	60.6	67.4	72.0	77.6

Figure 1. Assignment of Charges by Physician Specialty for the Aged and Disabled, 1975.

Specialties varied considerably with geography. Table 4 shows the rates of assignment for the four most frequently used specialties by census region.

Table 4. Medicare Beneficiaries: Assignment Rates for Aged and Disabled Beneficiaries by Selected Specialities and Census Region, 1975.

	United States		Northeast		North Central		South		West
Physician Specialty	Percent of Services Assigned	Percent of Charges Assigned	Percent of Services Assigned	Percent of Charges Assigned	Percent of Services Assigned	Percent of Charges Assigned	Percent of Services Assigned	Percent of Charges Assigned	Percent of Services Assigned	Percent of Charges Assigned
Aged:
Internal Medicine	44.1	48.3	55.8	58.3	26.5	33.2	34.4	36.1	1	1
General Practice	46.7	49.0	47.1	49.8	29.2	32.5	51.4	51.0	1	1
General Surgery	49.9	55.3	60.9	67.1	35.4	39.6	51.2	49.3	1	1
Radiology	59.0	55.5	72.6	64.7	45.3	40.7	62.6	57.7	1	1
Disabled:
Internal Medicine	57.2	64.2	65.2	72.3	52.1	58.3	51.0	54.0	1	1
General Practice	59.9	62.3	63.7	63.8	41.5	44.8	62.5	63.2	1	1
General Surgery	64.2	70.2	79.4	78.2	55.9	65.4	58.6	61.6	1	1
Radiology	70.0	68.8	83.9	82.6	63.5	61.1	69.2	65.7	1	1

¹See Table 2, footnote 1.

For the aged, the North Central region consistently had the lowest assignment rate among these four specialties. The Northeast region had the highest rate for internal medicine (55.8 percent), general surgery (60.9 percent), and radiology (72.6 percent). For the disabled, assignment rates were consistently higher in the Northeast compared to the South and North Central regions.

Physicians' Average Charge Per Service by Specialty and by Assignment

Table 5 shows the physicians' average submitted charge per service by specialty and by assignment. For the aged, average submitted charge by specialty ranged from a low of $6.76 per service by pathologists to a high of $50.30 per service by orthopedic surgeons. For the disabled, average charges ranged from $5.07 per service by pathologists to $47.98 per service by orthopedic surgeons.

Table 5. Medicare Beneficiaries: Average Submitted Charge Per Service for Assigned and Unassigned Services, 1975.

Physician Specialty	Aged: Average Submitted Charge				Disabled: Average Submitted Charge
	All Services	Assigned Services	Unassigned Services	Ratio of Assigned to Unassigned	All Services	Assigned Services	Unassigned Services	Ratio of Assigned to Unassigned
All Physicians	$19.47	$21.39	$18.95	1.13	$21.03	$23.08	$19.43	1.19
General Practice	11.35	12.19	11.12	1.10	11.25	11.96	10.80	1.11
Family Practice	11.50	12.40	11.06	1.12	11.72	12.54	10.81	1.16
Internal Medicine	15.48	17.18	14.54	1.18	16.92	19.30	14.38	1.34
Cardiovascular Disease	22.00	24.23	21.00	1.15	32.48	35.16	30.96	1.14
Dermatology	19.58	22.67	18.44	1.23	17.60	21.75	15.23	1.43
General Surgery	38.44	44.80	36.19	1.24	43.25	49.98	38.07	1.31
Otology/Rhinology/Laryngology	25.67	33.65	24.26	1.39	31.29	42.79	27.28	1.57
Ophthalmology	48.85	69.23	48.04	1.44	43.67	42.46	52.97	0.80
Orthopedic Surgery	50.30	60.73	46.30	1.31	47.98	54.01	45.98	1.17
Urology	40.71	48.23	39.82	1.21	30.44	36.60	26.59	1.38
Anesthesiology	n.a.	n.a.	n.a.	n.a.	n.a.	n.a.	n.a.	n.a.
Pathology	6.76	6.27	7.74	0.81	5.07	5.19	4.70	1.10
Radiology	18.28	17.30	19.99	0.87	18.08	17.95	18.95	0.95
Chiropractor, Licensed	9.13	9.92	8.79	1.13	9.43	9.60	9.20	1.04
Podiatry	18.57	21.59	16.04	1.35	21.87	24.82	18.41	1.35

For most specialties, the average charge per service was higher for assigned services in comparison to unassigned services. For the aged, exceptions to this rule were services by pathologists and radiologists. For the disabled, exceptions were for services by ophthalmologists and radiologists. For the aged, the ratio of average charge per service on assigned claims to average charge per service on unassigned claims reached a high of 1.44 for services by ophthalmologists, and for the disabled, the ratio reached 1.57 for services by otologists/rhinologists/laryngologists.

Average Percent Reduction

Under Medicare's Customary, Prevailing, and Reasonable Charge (CPR) mechanism, physicians' charges are passed through screens to determine the “reasonable” or “allowed” charge for each service. The total charges submitted by all physicians for services in 1975 were reduced 18.4 percent as a result of the CPR mechanism. Table 6 shows average percent reduction of submitted charges to allowed charges by specialty and by assignment. For the aged, the average percent reduction ranged from a low of 13.3 percent for charges by licensed chiropractors to a high of 23.6 percent for charges by anesthesiologists; for the disabled, the range was from 13.9 percent for charges by pathologists to 23.4 percent for charges by anesthesiologists. These differences by specialty in the rate of reduction of submitted charges reflect differences in charge patterns including differences by specialty in the rate of increase of current charges compared to charges submitted the previous calendar year (the period on which the reasonable charge determinations are based).

Table 6. Medicare Beneficiaries: Average Percent Reduction of Submitted Charges for Assigned and Unassigned Services by Physician Specialty, 1975.

	Aged: Average Percent Reduction			Disabled: Average Percent Reduction
Physician Specialty	All Charges	Assigned Charges	Unassigned Charges	All Charges	Assigned Charges	Unassigned Charges
All Physicians	18.4	18.5	18.2	19.6	19.6	19.4
General Practice	18.4	18.5	18.1	19.2	18.8	19.3
Family Practice	18.5	19.1	17.7	19.7	20.1	19.5
Internal Medicine	18.1	18.5	17.7	19.2	19.8	18.1
Cardiovascular Disease	19.3	19.3	19.2	20.2	22.0	17.7
Dermatology	17.4	18.9	15.8	16.6	16.8	15.9
General Surgery	18.8	19.5	17.8	20.3	21.4	18.0
Otology/Rhinology/Laryngology	20.0	20.1	19.9	19.6	20.4	18.6
Ophthalmology	17.0	17.0	16.8	18.2	19.0	17.1
Orthopedic Surgery	19.8	20.0	19.5	20.2	20.7	19.6
Urology	18.4	19.1	17.8	19.0	19.3	18.6
Anesthesiology	23.6	23.4	23.7	23.4	23.1	23.9
Pathology	16.5	14.9	19.2	13.9	13.0	15.6
Radiology	15.0	13.9	16.2	14.9	14.2	15.9
Chiropractor, Licensed	13.3	12.7	13.3	14.5	14.8	13.6
Podiatry	20.5	22.5	16.9	22.8	24.4	16.9

Examination of percent reduction by specialty according to assigned and unassigned charges shows that the percent reduction was generally a little higher on assigned charges in comparison to unassigned charges. For both the aged and disabled the most notable exceptions to this rule were charges by pathologists and radiologists.

It has been suggested that the size of the bill and the percent reduction on the bill are factors in the physician's decision to accept or reject assignment. In regard to these factors, one hypothesis is that as the size of the bill increases, the rate of assignment increases, because the larger the bill the greater the risk of the patient not being able to pay for it out-of-pocket. Thus, accepting assignment assures payment. Another hypothesis is that as the amount of reduction on the bill increases, the rate of assignment decreases, because refusing assignment allows the physician to recover the total charge from the patient.

Unfortunately, these hypotheses cannot be tested with the Medicare claims payment system. Under Medicare's system, if the beneficiary accumulates several bills from the same physician and submits them together they become one “claim.” Consequently, a $180 unassigned claim can actually represent bills for, say, a $50 service, a $30 service, and five $20 services rendered over a period of a year. Thus, the amount of a Medicare unassigned claim is an artifact of the way beneficiaries submit bills. Similarly, the percent reduction on an unassigned claim is an artifact of the way the beneficiary submits his or her bills, so that a 20 percent reduction on an unassigned claim can be the net effect of, say, a 30 percent reduction on a bill given to the beneficiary in February and a 15 percent reduction on a bill given to the beneficiary in July.

One hypothesis that can be tested is: Do the total charges a beneficiary accumulates from physicians over the year influence whether the charges will be assigned? The results of a special computer tabulation that groups beneficiaries by total annual charges per beneficiary indicates that the percent of charges assigned increases quite steadily as the beneficiaries' total charges increase. Table 7 (for all specialties) shows that for persons with annual charges under $100, only 38.2 percent were assigned. For persons with annual charges of $2,500 or more, 60.8 percent of the charges were assigned. Thus, it appears that the amount of total charges incurred by a beneficiary during the year is a determining factor in assignment decisions. Tabulations for general practice, internal medicine, general surgery, and radiology were also run (Tables 8, 9, 10, and 11). The results were similar except for radiology, which exhibited no clear pattern as total charges increased.

Table 7. Assigned Charges as a Percent of Total Charges from All Physicians, for the Aged, 1975.

Total Annual Charges per Beneficiary in 1975	Persons		Charges		Assigned Charges		Assigned Charges as a Percent of Total Charges
	Number	Percent of Total	Amount	Percent of Total	Amount	Percent of Total
			(in millions)		(in millions)
TOTAL	10,681,400	100.0	$4,375	100.0	$2,235	100.0	51.7
$ 1-99	3,065,100	28.7	164	3.8	63	2.8	38.2
100-149	1,470,400	13.8	180	4.1	68	3.0	37.4
150-199	1,054,200	9.9	182	4.2	75	3.3	41.0
200-249	753,200	7.1	168	3.8	73	3.3	43.5
250-299	555,300	5.2	151	3.5	70	3.1	46.4
300-349	439,400	4.1	142	3.2	66	2.9	46.4
350-399	352,400	3.3	132	3.0	66	2.9	49.8
400-499	529,200	5.0	236	5.4	115	5.2	48.8
500-699	698,600	6.5	413	9.4	208	9.3	50.3
700-999	642,800	6.0	538	12.3	275	12.3	51.2
1,000-1,499	544,700	5.1	662	15.1	349	15.7	52.7
1,500-1,999	264,800	2.5	455	10.4	248	11.1	54.7
2,000-2,499	125,600	1.2	280	6.4	152	6.8	54.3
2,500 +	185,700	1.7	671	15.4	408	18.3	60.8

Table 8. Assigned Charges as a Percent of Total Charges from General Practitioners, for the Aged, 1975.

Total Annual Charges per Beneficiary in 1975	Persons		Charges		Assigned Charges		Assigned Charges as a Percent of Total Charges
	Number	Percent of Total	Amount	Percent of Total	Amount	Percent of Total
			(in millions)		(in millions)
TOTAL	4,429,900	100.0	$637	100.0	$312	100.0	49.0
$ 1-99	2,408,100	54.5	110	17.4	44	14.0	39.6
100-149	687,400	15.5	84	13.1	35	11.4	42.3
150-199	404,200	9.1	69	10.9	32	10.3	46.2
200-249	257,400	5.8	57	9.0	27	8.6	47.2
250-299	169,800	3.8	46	7.3	24	7.5	50.9
300-349	120,400	2.7	39	6.1	20	6.5	52.4
350-399	85,300	1.9	32	5.0	17	5.4	53.3
400-499	109,000	2.5	48	7.6	26	8.2	52.8
500-699	97,800	2.2	57	8.9	32	10.2	56.0
700-999	58,200	1.3	48	7.5	29	9.2	60.0
1,000-1,499	24,900	0.6	30	4.7	17	5.6	58.5
1,500-1,999	4,300	0.1	7	1.1	4	1.2	52.6
2,000-2,499	1,600	0.04	3	0.5	2	0.7	59.3
2,500 +	1,500	0.03	6	0.9	4	1.2	64.6

Table 9. Assigned Charges as a Percent of Total Charges from Internal Medicine Specialists for the Aged, 1975.

Total Annual Charges per Beneficiary in 1975	Persons		Charges		Assigned Charges		Assigned Charges as a Percent of Total Charges
	Number	Percent of Total	Amount	Percent of Total	Amount	Percent of Total
			(in millions)		(in millions)
TOTAL	4,464,800	100.0	$903	100.0	$436	100.0	48.3
$ 1-99	1,964,000	44.1	96	10.6	32	7.3	33.6
100-149	718,500	16.1	88	9.7	30	7.0	34.6
150-199	465,900	10.4	80	8.9	33	7.6	41.2
200-249	296,300	6.6	66	7.3	30	6.8	45.0
250-299	197,100	4.4	54	6.0	25	5.8	46.8
300-349	151,600	3.4	49	5.4	24	5.5	49.2
350-399	117,100	2.6	44	4.8	20	4.7	46.9
400-499	157,400	3.5	70	7.8	36	8.2	50.6
500-699	178,700	4.0	105	11.6	56	12.8	53.2
700-999	119,400	2.7	99	10.9	54	12.5	55.1
1,000-1,499	61,700	1.4	74	8.2	43	9.9	58.5
1,500-1,999	21,500	0.5	36	4.0	22	5.0	59.8
2,000-2,499	9,000	0.2	20	2.2	12	2.7	59.6
2,500 +	6,600	0.1	23	2.6	18	4.2	79.2

Table 10. Assigned Charges as a Percent of Total Charges from General Surgeons for the Aged, 1975.

Total Annual Charges per Beneficiary in 1975	Persons		Charges		Assigned Charges		Assigned Charges as a Percent of Total Charges
	Number	Percent of Total	Amount	Percent of Total	Amount	Percent of Total
			(in millions)		(in millions)
TOTAL	1,899,700	100.0	$510	100.0	$282	100.0	55.3
$ 1-99	899,700	47.2	37	7.2	17	6.0	46.0
100-149	197,000	10.4	24	4.6	11	4.0	48.3
150-199	129,500	6.8	22	4.3	11	3.8	49.2
200-249	82,300	4.3	18	3.6	9	3.2	50.1
250-299	70,200	3.7	19	3.7	10	3.5	52.4
300-349	60,400	3.2	19	3.8	9	3.3	48.5
350-399	47,200	2.5	17	3.4	9	3.2	52.0
400-499	87,100	4.6	38	7.6	20	7.3	53.1
500-699	129,000	6.8	75	14.8	40	14.3	53.6
700-999	92,200	4.9	76	14.9	42	15.0	55.7
1,000-1,499	64,800	3.4	77	15.0	45	16.3	59.2
1,500-1,999	22,900	1.2	39	7.6	22	7.9	57.5
2,000-2,499	8,800	0.5	19	3.8	13	4.6	67.0
2,500 +	8,600	0.5	29	5.7	22	7.6	73.4

Table 11. Assigned Charges as a Percent of Total Charges from Radiologists for the Aged, 1975.

Total Annual Charges per Beneficiary in 1975	Persons		Charges		Assigned Charges		Assigned Charges as a Percent of Total Charges
	Number	Percent of Total	Amount	Percent of Total	Amount	Percent of Total
			(in millions)		(in millions)
TOTAL	2,607,400	100.0	$219	100.0	$122	100.0	55.5
$ 1-99	2,021,400	77.5	74	33.8	42	34.7	57.1
100-149	251,700	9.7	30	13.8	17	14.1	56.7
150-199	114,800	4.4	20	8.9	11	9.0	55.9
200-249	58,800	2.3	13	5.9	7	5.9	55.1
250-299	40,700	1.6	11	5.0	6	5.0	54.7
300-349	24,700	0.9	8	3.6	4	3.6	55.8
350-399	17,800	0.7	7	3.0	4	3.2	58.4
400-499	23,800	0.9	11	4.8	6	5.1	58.5
500-699	25,800	1.0	15	6.9	7	5.7	46.3
700-999	16,900	0.6	14	6.3	8	6.3	55.0
1,000-1,499	7,000	0.3	9	3.9	5	3.7	52.8
1,500-1,999	2,000	0.1	3	1.6	2	1.7	61.9
2,000-2,499	900	0.03	2	0.9	1	0.9	51.6
2,500 +	1,100	0.04	3	1.6	1	1.1	40.9

Impact of Unassigned Claims on Aged Beneficiaries

Unassigned claims affect a high proportion of the beneficiaries. In 1975, of the total Medicare beneficiaries in the U.S. who received payments for physician services, nearly 70 percent had some liability from unassigned claims, that is, liability for the difference between the physician's charges and the Medicare-allowed charges. Table 12 shows the percentage of users with liability from unassigned claims and the percentage of users with $100 or more of liability. The data show that in the U.S., 9.7 percent of the users were liable for $100 or more from unassigned claims.

Table 12. Medicare Beneficiaries: Percent of Aged Users with Unassigned Claims by State, 1975.

Area of Residence	Total Percent of Users with Unassigned Claims	Percent of Users with Liability of $100 or More on Unassigned Claims
United States	69.7	9.7
Northeast	71.8	8.6
New England	61.0	6.7
Maine	53.8	4.1
New Hampshire	69.6	9.5
Vermont	57.1	4.2
Massachusetts	51.3	4.6
Rhode Island	57.2	2.9
Connecticut	83.7	13.4
Middle Atlantic	75.4	9.2
New York	75.4	11.9
New Jersey	82.1	8.9
Pennsylvania	71.2	5.1
North Central	79.8	11.4
East North Central	79.8	11.8
Ohio	86.7	12.2
Indiana	88.3	12.6
Illinois	81.5	13.8
Michigan	64.2	7.3
Wisconsin	80.6	13.5
West North Central	79.6	10.7
Minnesota	80.1	10.8
Iowa	84.5	13.0
Missouri	79.7	10.6
North Dakota	78.3	9.5
South Dakota	87.2	11.2
Nebraska	85.4	12.5
Kansas	67.6	6.9
South	70.7	10.2
South Atlantic	75.2	11.4
Delaware	70.0	4.3
Maryland	66.8	7.5
District of Columbia	63.7	8.2
Virginia	69.4	9.1
West Virginia	67.6	7.1
North Carolina	69.6	6.4
South Carolina	64.1	3.9
Georgia	63.5	8.0
Florida	86.5	17.2
East South Central	63.1	8.7
Kentucky	72.3	11.3
Tennessee	72.0	11.1
Alabama	56.1	5.6
Mississippi	48.5	6.5
West South Central	67.8	9.2
Arkansas	66.6	7.0
Louisiana	68.4	11.2
Oklahoma	77.1	11.5
Texas	65.6	8.5
West	1	1
Mountain	79.7	12.4
Montana	86.8	8.0
Idaho	85.1	15.2
Wyoming	83.5	18.1
Colorado	71.0	7.5
New Mexico	75.7	10.0
Arizona	87.5	18.2
Utah	74.9	11.5
Nevada	77.3	12.7
Pacific	1	1
Washington	81.6	12.0
Oregon	93.3	16.9
California	1	1
Alaska	76.2	11.9
Hawaii	76.4	11.8

¹See Table 2, footnote 1.

It may be observed that there is a wide variation by State in the percentage of beneficiaries affected by unassigned claims. The highest percentage of users with liability was in Oregon where 93.3 percent were affected by unassigned claims. Table 12 also shows that nearly 17 percent of the users in Oregon were liable for $100 or more from unassigned claims.

Beneficiaries' Cost-Sharing

Beneficiary participation or cost-sharing begins with the fixed monthly premium. Additional cost-sharing in outlays for the deductible and coinsurance is a variable expense and depends upon use. Similarly, liability arising from unassigned claims is a variable expense that depends upon the level of use and charges for services.

Deductible, Coinsurance, and Liability on Unassigned Claims

Table 13 provides a breakdown of estimated variable expenses for physicians' services incurred by the aged. The total estimated variable expenses were $1.73 billion in 1975 or $79.17 per beneficiary. Of the total variable expense, the deductible accounted for 35.1 percent, coinsurance accounted for 39.8 percent, and liability from unassigned claims accounted for 25.1 percent. The data indicate that variable liability was higher for successively older age groups—an average of $66.07 per beneficiary for those aged 65-69 years to $92.89 per beneficiary for those aged 80-84 years; as age increased, so did use. Total variable expenses for males were estimated at $81.17 per beneficiary compared to $77.83 per beneficiary for females. A wide difference was seen by race with white beneficiaries averaging $82.52 in variable expenditures and non-white persons averaging $53.09; the difference reflected both lower use and a higher rate of assigned claims for non-white beneficiaries. By census region, expenditures ranged from $71.16 per beneficiary in the North Central region to $85.00 in the Northeast region.

Table 13. Medicare Beneficiaries: Variable Liability for Physicians' Services for the Aged, 1975.

	Total Variable Liability			Deductible					Coinsurance			Liability on Unassigned Claims
Age, Sex, Race, and Census Region	Total	Per Beneficiary	Percent	Total	For Users With Reimb.	For Users W/O1 Reimb.	Per Beneficiary	Percent	Total	Per Beneficiary	Percent	Total	Per Beneficiary	Percent
	(mil.)			(mil.)	(mil.)	(mil.)			(mil.)			(mil.)
Age:
65 and Over	$1725.5	$79.17	100.0	$604.8	$463.5	$141.3	$27.75	35.1	$687.2	$31.53	39.8	$433.5	$19.89	25.1
65-69	485.3	66.07	100.0	173.8	126.2	47.6	23.06	35.8	186.6	25.41	38.5	124.9	17.00	25.7
70-74	466.8	80.71	100.0	161.5	124.0	37.5	27.92	34.6	183.9	31.80	39.4	121.4	20.99	26.0
75-79	358.6	85.93	100.0	124.5	97.4	27.1	29.83	34.7	144.0	34.51	40.2	90.1	21.59	25.1
80-84	251.5	92.89	100.0	85.4	67.8	17.6	31.55	34.0	103.8	38.33	41.3	62.3	23.01	24.7
85 and Over	163.3	91.44	100.0	59.7	48.1	11.6	33.44	36.6	68.9	38.57	42.2	34.7	19.43	21.2
Sex:
Male	713.9	81.17	100.0	232.3	175.2	57.0	26.41	32.5	294.8	33.52	41.3	186.8	21.24	26.2
Female	1011.6	77.83	100.0	372.5	288.1	84.3	28.66	36.8	392.4	30.19	38.8	246.7	18.98	24.4
Race:
White	1605.2	82.52	100.0	552.8	426.7	126.1	28.42	34.4	635.9	32.69	39.6	416.5	21.41	26.0
All other Races	93.3	53.09	100.0	41.6	30.2	11.4	23.66	44.6	41.1	23.41	44.1	10.6	6.02	11.3
Census Region:
Northeast	462.0	85.00	100.0	155.9	120.7	35.2	28.68	33.7	198.2	36.47	42.9	107.9	19.85	23.4
North Central	427.4	71.16	100.0	149.5	110.6	38.9	24.89	35.0	155.8	25.94	36.5	122.1	20.33	28.5
South	512.6	74.88	100.0	188.4	144.0	44.4	27.52	36.8	187.1	27.33	36.5	137.1	20.03	26.7
West	2	2	2	110.7	88.1	22.6	31.74	2	145.7	41.77	2	2	2	2

¹Data in this table are estimates from claims from the 1-percent sample of beneficiaries except for this column. Deductible expenses for users without reimbursements are based on findings from the Current Medicare Survey.

²See Table 2, footnote 1.

Not all of these expenses are paid out-of-pocket by Medicare beneficiaries. Of the total aged beneficiaries enrolled in Part B, 11.3 percent were included under the Medicaid “buy-in” provision. In addition, more than half of Medicare beneficiaries have private health insurance which supplements Medicare coverage. These policies are quite varied and may cover some or all of the charges not reimbursed by Medicare.

Monthly Premium

The remaining source of beneficiary outlay is the fixed expenditure for the monthly premium. Table 14 shows the fixed premium expenditures as well as the variable expenditures as components of total beneficiary liability. The fixed annual Part B premium shown of $66.01 is a prorated figure based on reimbursements for physicians' services as a percentage of total Part B reimbursement.⁶

Table 14. Medicare Beneficiaries: Fixed and Variable Liability for Physicians' Services, for the Aged, 1975.

Age, Sex, Race, and Census Region	Total Beneficiary Liability			Fixed Expenditure (Premiums)1			Variable Liability
	Amount	Per Beneficiary	Percent	Amount	Per Beneficiary	Percent	Amount	Per Beneficiary	Percent
	(mil.)			(mil.)			(mil.)
Age:
65 and Over	$3,164.2	$145.18	100.0	$1,438.7	$66.01	45.5	$1,725.5	$79.17	54.5
65-69	970.2	132.08	100.0	484.9	66.01	50.0	485.3	66.07	50.0
70-74	848.6	146.72	100.0	381.8	66.01	45.0	466.8	80.71	55.0
75-79	634.1	151.94	100.0	275.5	66.01	43.4	358.6	85.93	56.6
80-84	430.2	158.90	100.0	178.7	66.01	41.5	251.5	92.89	58.5
85 and Over	281.1	157.45	100.0	117.8	66.01	41.9	163.3	91.44	58.1
Sex:
Male	1,294.5	147.18	100.0	580.6	66.01	44.9	713.9	81.17	55.1
Female	1,869.7	143.84	100.0	858.1	66.01	45.9	1,011.6	77.83	54.1
Race:
White	2,889.2	148.53	100.0	1,284.0	66.01	44.4	1,605.2	82.52	55.6
All other Races	209.3	119.10	100.0	116.0	66.01	55.4	93.3	53.09	44.6
Census Region:
Northeast	820.9	151.01	100.0	358.9	66.01	43.7	462.0	85.00	56.3
North Central	823.9	137.17	100.0	396.5	66.01	48.1	427.4	71.16	51.9
South	964.5	140.89	100.0	451.9	66.01	46.9	512.6	74.88	53.1
West	2	2	2	230.2	66.01	2	2	2	2

¹The monthly premium of $66.01 is a prorated figure based on 82 percent of the total SMI premium of $80.40: 82 percent represents physicians' charges as a percent of total Part B charges.

²See Table 2, footnote 1.

Overall, total beneficiary liability for physicians' services was estimated at $3.16 billion or $145.18 per beneficiary. Fixed expenditures (the premiums) represented 45.5 percent while variable expenditures made up 54.5 percent—(19.1 percent for the deductible, 21.7 percent for coinsurance, and 13.7 percent for liability on unassigned claims).

Medicare Reimbursements Compared to Beneficiary Liability

By comparing total beneficiary liability with Medicare reimbursements, the degree of insurance protection afforded the aged for physicians' services by the Medicare program can be further assessed. These total estimated expenditures of $4.57 billion or $209.81 per beneficiary are the physicians' charges less the charges above the allowed charges on assigned claims. Overall, the amount channeled through Medicare was $2.8 billion or 62.3 percent for physicians' services, while beneficiaries had liabilities (not including premiums) of $1.73 billion or 37.7 percent of total estimated expenditures for Part B physicians' services (Table 15). Per beneficiary, figures were $130.64 paid by Medicare and $79.17 for which the beneficiary was liable.

Table 15. Comparison of Payments for Physicians' Services: Amounts Paid by Medicare and Amounts for which Beneficiaries are Liable, 1975.

Age, Sex, Race, and Census Region	Total Physicians' Charges1			Paid by Medicare2			Beneficiary Liability3
	Amount	Per Beneficiary	Percent	Amount	Per Beneficiary	Percent	Amount	Per Beneficiary	Percent
	(mil.)			(mil.)			(mil.)
Age:
65 and Over	$4,572.8	$209.81	100.0	$2,847.3	$130.64	62.3	$1,725.5	$79.17	37.7
65-69	1,260.0	171.54	100.0	774.7	105.47	61.5	485.3	66.07	38.5
70-74	1,229.7	212.60	100.0	762.9	131.89	62.0	466.8	80.71	38.0
75-79	956.9	229.29	100.0	598.3	143.36	62.5	358.6	85.93	37.5
80-84	679.5	250.99	100.0	428.0	158.10	63.0	251.5	92.89	37.0
85 and Over	446.7	250.20	100.0	283.4	158.76	63.4	163.3	91.44	36.6
Sex:
Male	1,942.0	220.79	100.0	1,228.1	139.62	63.2	713.9	81.17	36.8
Female	2,630.8	202.39	100.0	1,619.2	124.56	61.5	1,011.6	77.83	38.5
Race:
White	4,238.0	217.87	100.0	2,632.8	135.35	62.1	1,605.2	82.52	37.9
All other Races	265.9	151.27	100.0	172.6	98.18	64.9	93.3	53.09	35.1
Census Region:
Northeast	1,255.5	230.96	100.0	793.5	145.96	63.2	462.0	85.00	36.8
North Central	1,088.4	181.21	100.0	661.0	110.05	60.7	427.4	71.16	39.3
South	1,311.6	191.60	100.0	799.0	116.72	60.9	512.6	74.88	39.1
West	4	4	4	592.4	169.84	4	4	4	4

¹Excludes charges above “reasonable” charge on assigned claims.

²Includes prorated premium contributions of beneficiaries.

³Excludes prorated premium contributions of beneficiaries.

⁴See Table 2, footnote 1.

Table 16 presents a different perspective by comparing the total liabilities of the beneficiaries (including the premium contributions as well as expenses due to the deductible, coinsurance, and the liability from unassigned claims) with the net Medicare contribution, that is, Medicare reimbursement less beneficiaries' premiums. The data indicate that the net amount contributed by public Medicare funds was $1.41 billion or 30.8 percent compared to $3.16 billion or 69.2 percent paid by or on behalf of the beneficiaries (that is, paid by the beneficiary or for the beneficiary, for example, by Medicaid or other insurance).

Table 16. Comparison of Contributions for Physicians' Services: Amounts Contributed by Medicare and Amounts for which Beneficiaries are Liable, 1975.

	Total Physicians' Charges1			Net Medicare Contribution2			Beneficiary Liability3
Age, Sex, Race, and Census Region	Amount	Per Beneficiary	Percent	Amount	Per Beneficiary	Percent	Amount	Per Beneficiary	Percent
	(mil.)			(mil.)			(mil.)
Aged:
65 and Over	$4,572.8	$209.81	100.0	$1,408.6	$64.63	30.8	$3,164.3	$145.18	69.2
65-69	1,260.0	171.54	100.0	289.8	39.46	23.0	970.2	132.08	77.0
70-74	1,229.7	212.60	100.0	381.1	65.88	31.0	848.6	146.72	69.0
75-79	956.9	229.29	100.0	322.8	77.35	33.7	634.1	151.94	66.3
80-84	679.5	250.99	100.0	249.3	92.09	36.7	430.2	158.90	63.3
85 and Over	446.7	250.20	100.0	165.6	92.75	37.1	281.1	157.45	62.9
Sex:
Male	1,942.0	220.79	100.0	647.5	73.61	33.3	1,294.5	147.18	66.7
Female	2,630.8	202.39	100.0	761.1	58.55	28.9	1,869.7	143.84	71.1
Race:
White	4,238.0	217.87	100.0	1,348.8	69.34	31.8	2,889.2	148.53	68.2
All other Races	265.9	151.27	100.0	56.6	32.17	21.3	209.3	119.10	78.7
Census Region:
Northeast	1,255.6	230.96	100.0	434.6	79.95	34.6	820.9	151.01	65.4
North Central	1,088.4	181.21	100.0	264.5	44.04	24.3	823.9	137.17	75.7
South	1,311.6	191.60	100.0	347.1	50.71	26.5	964.5	140.89	73.5
West	4	4	4	362.2	103.83	4	4	4	4

¹Excludes charges above “reasonable” charge on assigned claims.

²Excludes prorated premium contributions of beneficiaries. Source of funds are primarily General Revenues.

³Includes prorated premium contributions of beneficiaries.

⁴See Table 2, footnote 1.

Figure 2 provides a comparison of the data in Tables 15 and 16. The bar on the left represents the channeling of payments for total physicians' charges that are due (from Table 15) and the bar on the right represents the sources of the funds for total physicians' charges that are due (from Table 16). The figure also suggests the complexity of the mechanism for the funding and for the payment of benefits for physicians' services under Medicare; the large proportion representing “Beneficiary Liability” is paid from several sources including out-of-pocket, by Medicaid, and by Medigap policies (the term given to insurance policies that fill in Medicare gaps in coverage.)

Figure 2. Total Physicians' Charges Due: Comparison of Medicare Reimbursement with Net Medicare Contribution for the Aged, 1975.

Summary and Conclusions

This cross-sectional analysis shows that assignment rates vary considerably by geographic area and by specialty of the physician. In some areas of the nation, nearly all charges are assigned so that many of the beneficiaries are relieved of the burden of paying the physician any charges beyond those deemed “reasonable.” Additionally, beneficiaries residing in areas where physicians generally accept assignment are relieved of the burden of the paper work involved in submitting claims—which can be difficult and confusing to an older and perhaps ill beneficiary. In contrast, in areas where the assignment rate is low, a vast majority of the beneficiaries have these burdens to contend with.

This analysis shows that of the total physicians' charges (excluding charges above the allowed on assigned claims), the payments channeled through Medicare amounted to 62 percent while payments made by or on behalf of the beneficiaries for the deductible, coinsurance, and for liability on unassigned claims amounted to nearly 38 percent of total physicians' charges. The percentage of payments for which the beneficiaries were liable was very high relative to Medicare's Part A program—where beneficiary liability was less than 10 percent of hospital charges in 1975.

A majority of Medicare beneficiaries carry private insurance to supplement Part B coverage. Of course, for this coverage, beneficiaries must pay additional premiums that generally are set high enough to cover benefits and administrative costs.

This analysis also shows that of the total physicians' charges (excluding charges above the allowed on assigned claims), the net amount contributed by Medicare was 30 percent (excluding prorated premium contributions). The remaining 70 percent of physicians' charges are attributed to liability for premium payments by or on behalf of the beneficiaries and for the deductible, coinsurance, and the amount exceeding the allowed charge on unassigned claims.

Because the percentage increase in Medicare Part B premiums is restricted to no more than the percentage increase in social security beneficiaries' checks, premium payments by or on behalf of beneficiaries—as a percent of total Medicare Part B receipts—has been declining while the general revenue portion of total Medicare receipts has been rising. In 1978 the percent from general revenues reached 69.4 percent while the percent from premium payments by beneficiaries fell to 24.1 percent (Gibson, 1978). Thus, of the total Part B outlays, beneficiary contributions play a smaller role now than when Medicare began (approximately 50-50 contributions) and are likely to continue to decline. However, of the total physicians' charges that are liable for payment, the beneficiary portion may not simultaneously decline. First, the rate of reduction (that is, the difference between what the physicians charge and what Medicare allows) has been increasing (approximately 11 percent reduction in 1971 compared to 19 percent in 1975). Second, the assignment rate has generally been declining. Consequently, these forces may counteract the lower contribution of beneficiaries to Medicare outlays and may tend to keep up the amount of the total physicians' charges for which the beneficiaries are liable.

Technical Note

Reliability of Estimates^*

The data used in this paper are estimates based on a 1 percent sample (except for Table 5 which is based on a 5 percent sample) of the beneficiary population and hence are subject to sampling variability. Tables A through I will enable the reader to obtain approximate standard errors for the estimates in this paper. The standard error is primarily a measure of sampling variability—that is, of the variation that occurs by chance because a sample rather than the whole population is used. To calculate the standard errors at a reasonable cost for the wide variety of estimates in this paper, it was necessary to use approximation methods. Thus, these tables should be used only as indicators of the order of magnitude of the standard errors for specific estimates.

Table A. Approximate Standard Error of Estimated Dollars—Aged.

in thousands
Estimated Dollars	Standard Error
$100	$100
200	140
300	180
400	210
500	230
700	270
1,000	330
2,000	470
3,000	580
5,000	750
7,000	900
10,000	1,100
20,000	1,500
30,000	1,900
50,000	2,500
70,000	2,900
100,000	3,500
200,000	5,000
300,000	6,200
500,000	8,100
700,000	9,600
1,000,000	12,000
2,000,000	16,000
3,000,000	20,000
5,000,000	26,000

Table I. Approximate Relative Standard Error of Dollars Per Service—Aged and Disabled^*.

Base of Rate (services in thousands)	Relative standard error
10	.23
20	.17
30	.13
50	.10
70	.089
100	.076
200	.054
300	.043
500	.034
700	.028
1,000	.024
2,000	.017
3,000	.014
5,000	.011
7,000	.0089
10,000	.0076
20,000	.0054
30,000	.0044
50,000	.0034
70,000	.0029
100,000	.0024
200,000	.0017

^*This table is based on a 5 percent sample and is to be used only with estimates in Table 5.

The sample estimate and an estimate of its standard error permit us to construct interval estimates with prescribed confidence that the interval includes the average result of all possible samples (for a given sampling rate).

To illustrate, if all possible samples were selected, if each of these were surveyed under essentially the same conditions, and if an estimate and its estimated standard error were calculated from each sample, then:

1. Approximately ⅔ of the intervals from one standard error below the estimate to one standard error above the estimate would include the average value of all possible samples. We call an interval from one standard error below the estimate to one standard error above the estimate a ⅔ confidence interval.

2. Approximately ⁹/₁₀ of the intervals from 1.6 standard errors below the estimate to 1.6 standard errors above the estimate would include the average value of all possible samples. We call an interval from 1.6 standard errors below the estimate to 1.6 standard errors above the estimate a 90 percent confidence interval.

3. Approximately ¹⁹/₂₀ of the intervals from two standard errors below the estimate to two standard errors above the estimate would include the average value of all possible samples. We call an interval from two standard errors below the estimate to two standard errors above the estimate a 95 percent confidence interval.

4. Almost all intervals from three standard errors below the sample estimate to three standard errors above the sample estimate would include the average value of all possible samples.

The average value of all possible samples may or may not be contained in any particular computed interval. But for a particular sample, one can say with specified confidence that the average of all possible samples is included in the constructed interval.

The relative standard error is defined as the standard error of the estimate divided by the value being estimated. In general, estimates for small subgroups, and percentages or means with small bases tend to be relatively unreliable. The reader should be aware that some of the estimates in this paper have high relative standard errors.

The use of Tables A and B is straightforward. For example, the standard error of an estimated $100 million reimbursement is found to be $3.5 million. Simple linear interpolation may be used for values not tabled.

Table B. Approximate Standard Error of Estimated Number of Beneficiaries—Aged and Disabled.

Estimated Number of Persons	Standard Errors
100	100
200	140
300	170
500	220
700	260
1,000	320
2,000	450
3,000	550
5,000	710
7,000	840
10,000	1,000
20,000	1,400
30,000	1,700
50,000	2,200
70,000	2,600
100,000	3,200
200,000	4,500
300,000	5,400
500,000	7,000
700,000	8,200
1,000,000	9,800
2,000,000	14,000
3,000,000	16,000
5,000,000	20,000
7,000,000	22,000
10,000,000	24,000
12,000,000	24,000

Tables C through H are for estimated percentages or means per beneficiary and require knowledge of the number in the base of the estimate. Thee numbers can be found in Tables J through O. To illustrate their use, Table 13 shows the amount of deductible per beneficiary for age group 65-69 to be $23.06. The following steps, using double linear interpolation, show how to obtain the standard error of this estimate.

Table C. Approximate Standard Error of Percent Distribution of Number of Users—Aged and Disabled.

Percent	Base of percent (users In thousands)
	1	2	3	5	7	10	20	30	50	70	100	200	300	500	700	1,000	2,000	3,000	5,000	7,000	10,000	20,000
1 or 99	3.2	2.2	1.8	1.4	1.2	1.0	.71	.58	.45	.38	.32	.22	.18	.14	.12	.10	.071	.058	.045	.038	.032	.022
2 or 98	4.5	3.2	2.6	2.0	1.7	1.4	1.0	.82	.63	.53	.45	.32	.26	.20	.17	.14	.10	.082	.063	.053	.045	.031
3 or 97	5.5	3.9	3.2	2.5	2.1	1.7	1.2	1.0	.78	.66	.55	.39	.32	.25	.21	.17	.12	.10	.077	.065	.054	.038
4 or 96	6.3	4.5	3.7	2.8	2.4	2.0	1.4	1.2	.89	.76	.63	.45	.37	.28	.24	.20	.14	.12	.089	.075	.063	.044
5 or 95	7.1	5.0	4.1	3.2	2.7	2.2	1.6	1.3	1.0	.85	.71	.50	.41	.32	.27	.22	.16	.13	.099	.084	.070	.049
7 or 93	8.4	5.9	4.8	3.7	3.2	2.6	1.9	1.5	1.2	1.0	.84	.59	.48	.37	.32	.26	.19	.15	.12	.099	.082	.057
10 or 90	10	7.1	5.8	4.5	3.8	3.2	2.2	1.8	1.4	1.2	1.0	.71	.58	.45	.38	.32	.22	.18	.14	.12	.098	.067
20 or 80	14	10	8.2	6.3	5.3	4.5	3.2	2.6	2.0	1.7	1.4	1.0	.82	.63	.53	.45	.31	.26	.20	.16	.14	.090
30 or 70	17	12	10	7.8	6.5	5.5	3.9	3.2	2.4	2.1	1.7	1.2	1.0	.77	.65	.54	.38	.31	.24	.20	.16	.10
40 or 60	20	14	12	8.9	7.6	6.3	4.5	3.7	2.8	2.4	2.0	1.4	1.2	.89	.75	.63	.44	.36	.27	.22	.18	.11
50	22	16	13	10	8.5	7.1	5.0	4.1	3.2	2.7	2.2	1.6	1.3	.99	.84	.70	.49	.39	.30	.25	.20	.12

Table H. Approximate Standard Error for Percent Distribution of Services—Disabled.

Percent	Base of percent (services in thousands)
	5	7	10	20	30	50	70	100	200	300	500	700	1,000	2,000	3,000	5,000	7,000	10,000	20,000
1 or 99	9.6	8.3	7.1	5.3	4.4	3.5	3.0	2.6	1.9	1.6	1.3	1.1	.96	.71	.60	.48	.42	.36	.28
2 or 98	14	12	10	7.4	6.2	5.0	4.3	3.7	2.7	2.3	1.8	1.6	1.4	1.0	.84	.68	.59	.51	.39
3 or 97	16	14	12	9.0	6.6	6.0	5.2	4.5	3.3	2.8	2.2	1.9	1.6	1.2	1.0	.83	.72	.62	.47
5 or 95	21	18	16	11	9.6	7.7	6.6	5.7	4.2	3.5	2.8	2.4	2.1	1.6	1.3	1.1	.92	.79	.60
7 or 93	25	21	18	13	11	9.0	7.8	6.6	4.9	4.1	3.3	2.9	2.5	1.8	1.5	1.2	1.1	.93	.70
10 or 90	29	25	21	16	13	11	9.1	7.8	5.8	4.8	3.9	3.4	2.9	2.1	1.8	1.4	1.3	1.1	.83
20 or 80	38	33	28	21	17	14	12	10	7.6	6.4	5.1	4.4	3.8	2.8	2.4	1.9	1.7	1.4	1.1
30 or 70	43	37	32	23	20	16	14	12	8.6	7.2	5.8	5.0	4.3	3.2	2.7	2.2	1.9	1.6	1.2
50	46	39	34	25	21	17	14	12	9.1	7.7	6.1	5.3	4.5	3.4	2.8	2.3	2.0	1.7	1.3

Table J. Number of Part B Beneficiaries, 1975.

	Aged	Disabled
Total	21,795,120	1,945.209
Age:
Under 25		52,086
25-44		402,048
45-64		1,491,075
65-69	7,345,221	—
70-74	5,784,179	—
75-79	4,173,444	—
80-84	2,707,192	—
85 +	1,785,084	—
Sex:
Male	8,796,210	1,221,246
Female	12,998,910	723,963
Race:
White	19,451,455	1,610,596
All other Races	1,758,041	297,975

Table O. Total Number of Users and Number of Users with Unassigned Claims for the Aged by State, 1975.

Area of Residence	Total Number of Users (in thousands)	Number of Users with Unassigned Claims (in thousands)
United States	10,822	7,541
Northeast	2,828	2,032
New England	697	425
Maine	59	32
New Hampshire	43	30
Vermont	29	17
Massachusetts	335	172
Rhode Island	72	41
Connecticut	160	134
Middle Atlantic	2,130	1,607
New York	1,063	801
New Jersey	414	340
Pennsylvania	654	466
North Central	2,714	2,164
East North Central	1,806	1,442
Ohio	468	406
Indiana	238	210
Illinois	468	381
Michigan	397	255
Wisconsin	235	190
West North Central	908	723
Minnesota	205	164
Iowa	164	139
Missouri	260	207
North Dakota	40	31
South Dakota	32	28
Nebraska	75	64
Kansas	132	89
South	3,278	2,319
South Atlantic	1,664	1,252
Delaware	26	18
Maryland	135	90
District of Columbia	32	20
Virginia	177	123
West Virginia	79	54
North Carolina	221	154
South Carolina	99	63
Georgia	196	125
Florida	699	604
East South Central	586	370
Kentucky	128	92
Tennessee	183	132
Alabama	159	89
Mississippi	116	56
West South Central	1,028	698
Arkansas	132	88
Louisiana	143	98
Oklahoma	154	119
Texas	600	393
West	1,996	1,024
Mountain	413	329
Montana	33	28
Idaho	36	31
Wyoming	13	11
Colorado	110	78
New Mexico	45	34
Arizona	114	100
Utah	39	29
Nevada	23	18
Pacific	1,584	695
Washington	198	161
Oregon	126	118
California	1,224	388
Alaska	4	3
Hawaii	32	25

1. Table J shows the number of beneficiaries in the base to be 7,345,221.

2. In Table D we find:

   1. Standard error for $20.00 and 7 million enrolled—$.60.

   2. Standard error for $30.00 and 7 million enrolled—$.74.

3. The interpolated standard error for $23.06 and 7 million is $.64.

4. Again in Table D we find:

   1. Standard error for $20.00 and 10 million enrolled—$.50.

   2. Standard error for $30.00 and 10 million enrolled—$.62.

5. The interpolated standard error for $23.06 and 10 million is $.54.

6. Interpolating between $.64 and $.54 for the 7,345,221 beneficiaries in the base, we find the standard error of the estimate to be $.63.

Table D. Approximate Standard Error of Estimated Dollars per Beneficiary—Aged.

Dollars per Beneficiary	Base of rate (persons enrolled in thousands)
	1	2	3	5	7	10	20	30	50	70	100	200	300	500	700	1,000	2,000	3,000	5,000	7,000	10,000	20,000
$10	10	10	10	10	10	10	7.2	5.9	4.6	3.9	3.3	2.4	1.9	1.5	1.3	1.1	.77	.63	.49	.42	.35	.25
20	20	20	20	20	17	14	10	8.4	6.6	5.6	4.7	3.4	2.8	2.2	1.8	1.5	1.1	.90	.71	.60	.50	.36
30	30	30	30	25	21	18	13	10	8.1	6.9	5.8	4.1	3.4	2.7	2.3	1.9	1.4	1.1	.87	.74	.62	.44
50	50	50	41	32	27	23	16	14	11	9.0	7.5	5.4	4.4	3.5	2.9	2.5	1.8	1.5	1.1	.96	.81	.58
70	70	60	49	38	33	27	20	16	13	11	9.0	6.4	5.3	4.1	3.5	2.9	2.1	1.7	1.3	1.1	.96	.69
100	100	72	59	46	39	33	24	19	15	13	11	7.7	6.3	4.9	4.2	3.5	2.5	2.1	1.6	1.4	1.2	.82
200	140	100	84	66	56	47	34	28	22	18	15	11	9.0	7.1	6.0	5.0	3.6	3.0	2.3	2.0	1.7	1.2
300	180	130	100	81	69	58	41	34	27	23	19	14	11	8.7	7.4	6.2	4.4	3.6	2.8	2.4	2.0	1.5
500	230	160	140	110	90	75	54	44	35	29	25	18	14	11	9.6	8.1	5.8	4.7	3.7	3.1	2.6	1.9
700	270	200	160	130	110	90	64	53	41	35	29	21	17	13	11	9.6	6.9	5.6	4.4	3.7	3.1	2.2

Table I contains the relative standard error of dollars per service. (Note that this table is based on a 5 percent sample whereas all other standard error tables are based on a 1 percent sample). To illustrate its use, assume we have an estimate of $18 per service based on 7,000,000 services. The relative standard error is .0089 and the standard error .0089 × $18 = $.16.

Table E. Approximate Standard Error of Percent Distribution of Dollars—Aged.

Percent	Base of percent (dollars in millions)
	$1	$2	$3	$5	$7	$10	$20	$30	$50	$70	$100	$200	$300	$500	$700	$1,000	$2,000	$3,000	$5,000
1 or 99	3.3	2.4	2.0	1.5	1.3	1.0	.78	.64	.50	.42	.36	.26	.21	.17	.14	.12	.088	.075	.061
2 or 98	4.7	3.3	2.7	2.1	1.8	1.5	1.1	.90	.70	.60	.50	.36	.30	.23	.20	.17	.12	.10	.086
3 or 97	5.7	4.1	3.3	2.6	2.2	1.9	1.3	1.1	.86	.73	.61	.44	.36	.28	.24	.21	.15	.13	.10
5 or 95	7.3	5.2	4.3	3.3	2.8	2.4	1.7	1.4	1.1	.93	.78	.56	.46	.36	.31	.26	.19	.16	.13
7 or 93	8.5	6.1	5.0	3.9	3.3	2.8	2.0	1.6	1.3	1.1	.91	.66	.54	.42	.36	.31	.23	.19	.16
10 or 90	10	7.2	5.9	4.6	3.9	3.3	2.3	1.9	1.5	1.3	1.1	.77	.63	.50	.43	.36	.26	.22	.18
20 or 80	13	9.5	7.8	6.1	5.2	4.4	3.1	2.6	2.0	1.7	1.4	1.0	.84	.66	.56	.48	.35	.29	.24
30 or 70	15	11	8.9	7.0	5.9	5.0	3.6	2.9	2.3	1.9	1.6	1.2	.96	.75	.64	.54	.40	.33	.27
50	16	12	9.7	7.5	6.4	5.4	3.9	3.2	2.5	2.1	1.8	1.3	1.0	.81	.69	.59	.43	.36	.29

Table F. Approximate Standard Error of Percent Distribution of Dollars—Disabled.

Percent	Base of percent (dollars in millions)
	$1	$2	$3	$5	$7	$10	$20	$30	$50	$70	$100	$200	$300	$500
1 or 99	4.2	3.1	2.6	2.1	1.8	1.5	1.1	.93	.74	.63	.54	.40	.33	.26
2 or 98	6.0	4.4	3.7	2.9	2.5	2.1	1.6	1.3	1.0	.89	.76	.56	.47	.37
3 or 97	7.3	5.3	4.4	3.5	3.0	2.6	1.9	1.6	1.3	1.1	.93	.68	.57	.45
5 or 95	9.3	6.8	5.7	4.5	3.9	3.3	2.4	2.0	1.6	1.4	1.2	.87	.72	.58
7 or 93	11	7.9	6.6	5.3	4.5	3.9	2.8	2.4	1.9	1.6	1.4	1.0	.85	.67
10 or 90	13	9.3	7.8	6.2	5.3	4.5	3.3	2.8	2.2	1.9	1.6	1.2	.99	.79
20 or 80	17	12	10	8.2	7.0	6.0	4.4	3.7	2.9	2.5	2.1	1.6	1.3	1.0
30 or 70	19	14	12	9.3	8.0	6.8	5.0	4.2	3.3	2.9	2.4	1.8	1.5	1.2
50	20	15	12	9.9	8.5	7.3	5.3	4.4	3.5	3.0	2.6	1.9	1.6	1.3

Table G. Approximate Standard Error for Percent Distribution of Services—Aged.

Percent	Base of percent (services in thousands)
	10	20	30	50	70	100	200	300	500	700	1,000	2,000	3,000	5,000	7,000	10,000	20,000	30,000	50,000	70,000	100,000	200,000	300,000
1 or 99	7.1	5.0	4.1	3.2	2.7	2.3	1.6	1.3	1.0	.87	.73	.52	.42	.33	.28	.24	.17	.14	.11	.094	.081	.061	.053
2 or 98	10	7.1	5.8	4.5	3.8	3.2	2.3	1.9	1.4	1.2	1.0	.73	.60	.46	.39	.33	.24	.20	.15	.13	.11	.086	.074
3 or 97	12	8.6	7.1	5.5	4.7	3.9	2.8	2.3	1.8	1.5	1.3	.89	.73	.57	.48	.40	.29	.24	.19	.16	.14	.10	.090
5 or 95	16	11	9.0	7.0	5.9	5.0	3.5	2.9	2.3	1.9	1.6	1.1	.93	.72	.61	.52	.37	.30	.24	.21	.18	.13	.12
7 or 93	18	13	11	8.2	7.0	5.8	4.1	3.4	2.6	2.2	1.9	1.3	1.1	.85	.72	.60	.43	.36	.28	.24	.21	.16	.13
10 or 90	21	15	12	9.7	8.2	6.9	4.9	4.0	3.1	2.6	2.2	1.6	1.3	.99	.84	.71	.51	.42	.33	.28	.24	.18	.16
20 or 80	28	20	17	13	11	9.1	6.5	5.3	4.1	3.5	2.9	2.1	1.7	1.3	1.1	.94	.67	.56	.44	.37	.32	.24	.21
30 or 70	33	23	19	15	12	10	7.4	6.1	4.7	4.0	3.4	2.4	2.0	1.5	1.3	1.1	.77	.63	.50	.43	.36	.27	.23
50	35	25	21	16	14	11	8.1	6.6	5.7	4.3	3.6	2.6	2.1	1.7	1.4	1.2	.84	.69	.54	.46	.39	.29	.24

Table K. Number of Physicians' Services and Charges for the Aged and Disabled by State, 1975.

	Aged		Disabled
Area of Residence	Number of Services (in thous)	Total Charges (in thous)	Number of Services (in thous)	Total Charges (in thous)
United States	260,658	$4,904,585	21,855	$446,661
Northeast	67,265	1,386,394	4,468	105,984
New England	16,227	297,762	878	19,441
Maine	1,573	22,077	121	2,633
New Hampshire	1,151	15,251	62	1,052
Vermont	693	9,499	39	1,118
Massachusetts	7,820	146,856	436	8,764
Rhode Island	1,695	30,605	86	2,146
Connecticut	3,296	73,473	135	3,728
Middle Atlantic	51,038	1,088,632	3,590	86,543
New York	26,707	614,850	1,658	40,399
New Jersey	9,646	194,935	822	20,725
Pennsylvania	14,685	278,847	1,110	25,419
North Central	62,857	1,121,718	4,993	91,601
East North Central	41,084	760,148	3,643	68,746
Ohio	12,399	178,530	1,101	16,039
Indiana	5,446	87,238	515	8,175
Illinois	10,800	215,015	741	17,841
Michigan	5,638	174,527	649	18,578
Wisconsin	6,801	104,838	637	8,113
West North Central	21,773	361,570	1,349	22,855
Minnesota	4,735	80,177	246	4,969
Iowa	3,536	58,160	207	3,418
Missouri	7,135	112,844	534	8,023
North Dakota	1,018	13,142	76	902
South Dakota	733	11,177	35	666
Nebraska	1,949	32,160	116	2,132
Kansas	2,668	53,910	137	2,746
South	82,217	1,379,299	7,928	141,370
South Atlantic	39,312	735,110	3,786	72,923
Delaware	601	8,693	65	751
Maryland	2,748	58,625	258	6,112
District of Columbia	773	18,481	44	1,080
Virginia	4,096	69,920	466	8,995
West Virginia	1,815	25,495	199	3,186
North Carolina	4,998	77,080	592	9,750
South Carolina	2,227	33,646	335	5,568
Georgia	4,812	78,270	792	14,159
Florida	17,242	364,902	1,037	23,323
East South Central	14,902	210,692	1,742	27,445
Kentucky	2,869	42,859	258	4,413
Tennessee	4,559	67,144	627	10,316
Alabama	3,632	58,011	453	8,102
Mississippi	3,842	42,677	404	4,614
West South Central	28,003	433,497	2,400	41,002
Arkansas	4,130	50,443	330	5,371
Louisiana	3,413	57,572	352	6,428
Oklahoma	3,833	60,541	280	5,148
Texas	16,628	264,941	1,439	24,055
West	48,218	1,014,644	4,449	106,970
Mountain	9,609	185,404	949	19,077
Montana	555	8,447	63	897
Idaho	936	13,806	69	1,219
Wyoming	335	5,608	15	208
Colorado	2,516	46,367	352	6,094
New Mexico	1,211	21,408	67	1,293
Arizona	3,008	62,137	272	5,601
Utah	579	15,351	34	1,114
Nevada	469	12,280	78	2,650
Pacific	38,609	829,241	3,499	87,893
Washington	4,496	83,181	339	6,603
Oregon	2,957	53,705	251	4,805
California	30,381	676,745	2,846	75,311
Alaska	96	2,130	10	188
Hawaii	680	13,480	53	985

Table L. Number of Services and Charges by Physicians' Specialty for the Aged, 1975.

Physician Specialty	Total Services (in thous)	Assigned Services (in thous)	Unassigned Services (in thous)	Total Charges (in thous)	Assigned Charges (in thous)	Unassigned Charges (in thous)
All Physicians	234,931	104,492	112,892	$4,573,055	$2,234,946	$2,139,734
General Practice	60,644	25,607	29,193	688,325	312,148	324,699
Family Practice	5,752	2,578	2,730	66,138	31,968	30,199
Internal Medicine	60,946	25,366	32,114	943,649	435,664	466,994
Cardiovascular Disease	5,726	2,558	2,847	125,962	61,965	59,764
Dermatology	2,897	1,127	1,415	56,735	25,544	26,085
General Surgery	13,546	6,285	6,299	520,692	281,545	227,967
Otology/Rhinology/Laryngology	2,236	677	1,234	57,407	22,768	29,934
Ophthalmology	5,979	1,751	3,217	292,052	121,242	154,534
Orthopedic Surgery	4,926	2,108	2,472	247,772	128,030	114,474
Urology	5,774	2,401	2,853	235,067	115,789	113,620
Anesthesiology	9,823	5,089	4,610	206,269	105,134	99,459
Pathology	5,740	3,746	1,834	38,813	23,483	14,203
Radiology	12,678	7,034	4,883	231,689	121,700	97,630
Chiropractor, Licensed	2,758	826	1,754	25,175	8,195	15,410
Podiatry	4,081	2,124	1,382	75,765	45,846	22,162

Table M. Number of Services and Charges by Physicians' Specialty for the Disabled, 1975.

Physician Specialty	Total Services (in thous)	Assigned Services (in thous)	Unassigned Services (in thous)	Total Charges (in thous)	Assigned Charges (in thous)	Unassigned Charges (in thous)
All Physicians	19,302	11,123	7,034	$405,948	$256,733	$136,689
General Practice	4,238	2,308	1,545	47,662	27,606	16,679
Family Practice	420	240	156	4,924	3,012	1,690
Internal Medicine	4,883	2,661	1,989	82,624	51,352	28,605
Cardiovascular Disease	438	239	180	14,214	8,410	5,570
Dermatology	130	51	63	2,288	1,105	957
General Surgery	1,031	615	343	44,564	30,759	13,060
Otology/Rhinology/Laryngology	144	51	77	4,497	2,182	2,109
Ophthalmology	206	80	98	8,974	3,397	5,165
Orthopedic Surgery	515	251	232	24,690	13,563	10,662
Urology	445	228	185	13,553	8,333	4,906
Anesthesiology	1,012	640	363	19,330	12,173	7,016
Pathology	643	453	179	3,258	2,349	840
Radiology	1,025	684	293	18,529	12,271	5,558
Chiropractor, Licensed	227	101	111	2,141	967	1,022
Podiatry	153	96	37	3,335	2,370	685

Table N. Number of Physicians' Services and Charges for the Aged and Disabled by Census Region¹ and Selected Specialties, 1975.

	United States		Northeast		North Central		South
	Number of Services	Number of Charges	Number of Services	Number of Charges	Number of Services	Number of Charges	Number of Services	Number of Charges
Aged:
Internal Medicine	60,946	$943,649	20,003	$325,371	13,217	$193,316	17,153	$248,968
General Practice	60,644	688,325	11,847	139,665	14,790	162,139	23,109	237,952
General Surgery	13,546	520,692	3,401	156,447	3,806	127,090	4,422	143,326
Radiology	12,678	231,689	2,257	47,931	3,488	54,925	5,023	85,049
Disabled:
Internal Medicine	4,883	82,624	1,321	24,209	1,010	15,998	1,711	25,599
General Practice	4,238	47,662	633	7,502	866	9,169	1,839	18,421
General Surgery	1,031	44,564	197	12,026	277	9,406	401	14,814
Radiology	1,025	18,529	133	2,641	276	4,419	454	7,722

¹See Table 2, footnote 1 in text.