enrollment, however, it is necessary to make a deduction for duplication between insurance companies and independent plans.

Use of the procedure outlined above yields estimates of net enrollment for hospital and surgical coverage of about the same level of magnitude as the HIAA estimates of net enrollment for these services. Because the basis for an independent estimate of the extent of duplicatory coverage is not fully firm and the figures of net enrollment thus developed are not materially different from those the HIAA publishes, the HIAA estimates of net enrollment for hospital, surgical, and inhospital medical coverage are used here, as shown in tables 1, 2, and 3.

For the other services, no studies of the extent of duplication, either within the insurance industry or among the different groups of carriers, have been made. (There is every reason to believe that the extent of duplicatory coverage in these services is less than that in hospital, surgical, and in-hospital coverage and varies with the gross enrollment. Factors of duplicatory coverage have therefore been assumed that seem reasonable in relation to those estimated for the three primary services.)

As previously mentioned, all estimates of coverage based upon enrollment reported by health insurance organizations run higher than estimates of coverage based on household surveys. The findings of the Public Health Service 196263 survey on the number of persons with hospital and surgical coverage at the end of 1962, increased by the percentage rise in gross enrollment between 1962 and 1966 shown by the Office of Research and Statistics data, yields an estimate of 146.4 million persons covered at the end of 1966 for hospital care (75.2 percent of the civilian population) and 136.8 million covered for surgery (70.3 percent of the civilian population).

The most nearly precise statement that can now be made on the extent of private health insurance coverage at the end of 1966 is that it is probably within the range of 75-81 percent of the population for hospital coverage and 70-74 percent of the population for surgical coverage.

7 For a brief description of the HIAA methods of estimating duplicatory coverage, both within the insurance industry and among the three types of carriers, see Louis S. Reed, The Extent of Health Insurance Coverage in the United States (Research Report No. 10), 1965.

Interpretation of the Data

Some notes on the extent of coverage shown for certain services are required. The figures for X-ray and laboratory examinations include only persons covered for these services in doctors' offices or clinics and for all types of cases. They do not include persons covered for these services only in hospital outpatient departments or only in accident or fracture cases or when the examination is later followed by surgery. Substantial numbers of Blue Cross and Blue Shield members have the latter type of restricted coverages.

The figures on persons covered for physicians' office and home visits likewise include only persons entitled to such services for all conditions. and do not include substantial numbers of Blue Cross-Blue Shield members covered for office and home visits only for continued care after hospitalization. Similarly, with respect to out-ofhospital prescribed drugs, persons covered for drugs only for continued care after hospitalization are excluded.

The figures on dental coverage relate only to persons with coverage of at least dental diagnosis, fillings, and extractions-in other words, a fairly broad coverage—and exclude persons covered only for dental care required as a result of an accident or when dental surgery must be performed in a hospital. Virtually all persons with major medical coverage have the first type of restricted coverage, and most Blue Shield plans cover dental surgery in a hospital.

The coverage shown for private-duty nursing relates to services of a registered nurse in the hospital or home, though some policies will also cover services of a practical nurse in the hospital. The large number of people shown as covered for visiting-nurse service may seem surprising. Major medical policies agree to reimburse for the cost of services of a registered nurse. Visiting nurses are registered nurses, and the policies do not specify that service must be for at least 8 hours a day. Such policies would therefore reimburse for charges for visiting-nurse service. It has been assumed that all persons covered for private-duty nursing are also covered for visiting-nurse service, although the use of visiting nurse service by those covered for private-duty nursing is actually infrequent. The difference between the number of persons with private-duty nursing coverage and

the number with visiting-nurse coverage represents the fairly substantial numbers of persons covered for visiting-nurse service but not privateduty nursing by Blue Cross and certain independent plans. Persons covered for visiting-nurse service only after hospitalization are includedsince it was deemed that for this service the restriction is of minor importance.

The figures on persons covered for nursinghome care or care in extended-care facilities do include those entitled to such care only after hospitalization—a rather common provision in Blue Cross coverage and one that also exists under Medicare. The figures for nursing home coverage by Blue Cross-Blue Shield plans and by independent plans can be considered as reliable. Those for persons covered by insurance companies represent only an informed guess.

Major Medical and Extended-Benefit Coverage

Most of the coverage shown for physicians' office and home visits, prescribed drugs, privateduty nursing, visiting-nurse service and a large share of that for nursing-home care is under insurance company major medical policies or supplementary major medical provisions of Blue Cross-Blue Shield that is, under provisions where the insurance pays 80 or 75 percent of the cost over and above a deductible. By contrast the coverage of these services by the independent plans is mainly of the so-called basic or firstdollar type.

The HIAA reports the following number of persons covered under major medical policies of insurance companies at the end of 1966:

drugs, and private-duty nursing (and visitingnurse service also) and a small proportion also covers nursing-home care. Persons covered under these policies account for all or the vast majority of the number shown as covered for the abovementioned services by insurance companies.

The number shown as covered by insurance companies for X-ray and laboratory examinations and for physicians' office and home visits is believed to be understated by a considerable margin. It is estimated from HIAA data that 34.2 million persons under age 65 have basic (first-dollar) coverage of X-ray and laboratory examinations and another 12.1 million are covered for these services under comprehensive major medical policies. But 38.8 million persons under age 65 are also covered for these services under supplementary major medical policies, bringing the total— after some allowance for persons with both basic and supplementary major medical coverage—to perhaps 77 million. Similarly, HIAA data show about 8.2 million persons with basic coverage of physicians' office and home visits. This number, together with the 12.1 million covered under comprehensive major medical policies and the 38.8 million covered under supplementary major medical policies would bring the total to about 55 million (again with allowance for duplication). To have used these figures instead of the estimates shown in table 2 would have thrown the coverage for such services out of line with the coverage shown by the HIAA for physician in-hospital visits, which is certainly larger than for either of the other two services.8

8 Basically the discrepancies arise from the fact that the HIAA, in making its estimates of persons covered for hospital care, surgery, and what it calls "regular medical" coverage counts only those with basic coverage and comprehensive major medical coverage and excludes those with supplementary major medical coverage on the grounds that they are already included in the count of persons with basic coverage. This is probably true for hospital care and surgery but not true for in-hospital visits, since appreciable numbers of persons have the latter coverage only through supplementary major medical policies. The HIAA figure for in-hospital medical visits is therefore almost certainly too low.

The HIAA at the request of the Office of Research and Statistics has asked five of the larger companies to study a small sample of their larger supplementary major medical policies to determine what services these policies cover and what are the basic coverages they supplement (and whether through insurance companies or Blue Cross-Blue Shield plans). The results will be available too late to be taken into account here, but they should aid in more accurate reporting next year.

The Blue Cross Association and the National Association of Blue Shield Plans report that the unduplicated number of Blue Cross-Blue Shield. members with supplementary major medical coverage is 10,409,000 with an additional 3,943,000 covered under extended benefit provisions. Both counts exclude aged persons with complementary coverage. The supplementary coverage in virtually all cases covers X-ray and laboratory examinations, physicians' office and home visits, drugs, private-duty nursing, and visiting-nurse service. The extended-benefit contracts frequently cover physicians' office and home visits, prescribed drugs, and visiting-nurse service but generally only after hospitalization. Most of the Blue Cross-Blue Shield coverage of physicians' office and home visits is under supplemental major medical provisions, including the supplemental major medical provisions of complementary contracts. Blue Shield plans report only 3.2 million persons with basic coverage of office and home visits 6 percent of the total membership.

Shares of the Carriers in Enrollment

The shares of the three groups of health insurance organizations in the total gross enrollment for each type of service are indicated in table 4. It is evident that, among the population of all ages and among those under age 65, insurance

9 An additional 3,683,000 persons are covered under dread-disease or prolonged-illness coverage, but because the coverage is restricted to certain diseases they are not considered here.

companies have considerably more enrollment for most services than Blue Cross-Blue Shield plans, and that the insurance companies have made considerably further progress in providing the newer services (those other than for hospital care, surgery, and in-hospital medical services). In general, this growth has resulted from the wide sale of major medical policies by insurance companies.

The independent plans cut only a small figure in the total enrollment for the older types of coverage but show strength in the coverage of X-ray and laboratory examinations and physicians' office and home calls-a reflection, of course, of the emphasis given by these plans to comprehensive coverage of physician services. The independent plans also play a major role in dental coverage.

The picture is different with respect to the aged. Blue Cross and Blue Shield plans have been relatively more successful than insurance companies in the sale of complementary coverage to older people.

In considering these figures, it should be borne in mind that Blue Cross-Blue Shield coverage of hospital care and physician services is generally somewhat deeper or more extensive than that of the insurance companies especially in comparison with individual insurance company policies. The data on benefit expenditures per covered person, presented later in this article, make this point clear. For premiums or benefit expenditures, the Blue Cross-Blue Shield plans' share in the total is slightly larger and the shares of the insurance companies slightly smaller than their respective shares in total enrollment.

Quality of Coverage

It is important, of course, to know the number of persons who have some protection against the various types of medical care costs. To appraise the contribution of voluntary health insurance to the health and welfare of the American people, however, much more knowledge is required. It is essential to know how good and how extensive the coverage is and to what degree it affords security against burdensome medical costs and removes financial barriers to the receipt of care.

The Blue Cross plans have made considerable efforts to present meaningful data on the extent of service available to covered persons. One survey shows that, at the end of 1965, approximately 8 percent of the members were covered for 21-69 days of care, 18 percent for 70-119 days, 47 percent for 120 or more days, and 8 percent for 21365 days; in addition, 18 percent were covered for some combination of full and partial benefits that adds to 120 days or more and 1 percent for some combination of full and partial benefits that adds to less than 120 days.10

Of the members in plans reporting these data, 67 percent were covered for the full room cost in semiprivate accommodations, 5 percent for a percentage of the cost in semiprivate accommodations, 22 percent for the full room cost in ward accommodations, 16 percent for a dollar allowance against the room cost, and 9 percent for other benefits.

Of plans with a total membership of about 56 million that cover laboratory examinations, approximately nine-tenths of the members were covered for all laboratory examinations and onetenth had only partial coverage. In some places, Blue Shield provides this service. Of plans with 45 million members that cover X-ray examinations, again almost nine-tenths were covered for all X-ray examinations and about one-tenth had partial coverage. Some 53 million Blue Cross members at the end of 1965 had full coverage of anesthesia supplies, and 2.5 million had partial coverage.

Virtually all Blue Cross members are covered in full for use of the operating room, according to a survey for 1964. The same survey found that 98.5 percent of Blue Cross members were covered

10 Blue Cross Association, Statistical Bulletin No. 8, October 13, 1966.

in full for drugs during their period of benefit coverage.11

Reasonably complete data on the number of Blue Shield members covered for different services are available. At the end of 1966, 89 percent of those enrolled in the United States were covered under basic contracts for anesthesia service, 72 percent for office X-ray examinations (with about 60 percent of this group covered in all types of cases), 59 percent for office laboratory examinations (with about 60 percent covered in all types of cases), 6 percent for office and home visits, and 94 percent for in-hospital medical visits. What is not known is how many of these persons are entitled to full coverage of doctors' charges for these services that is, to full service benefits.

Most persons covered under community-consumer independent plans have a hospital coverage as good or better than that of the average Blue Cross member, and they are entitled to all necessary services of physicians in the office, home, and hospital. Coverage under the employer-employeeunion plans varies widely.

The greatest gap in knowledge of the quality of health insurance coverage is the lack of adequate data on insurance company coverage. The annual surveys of the Health Insurance Institute, New Group Policies Issued, though useful do not give a reliable picture of the extent and depth of coverage possessed by the insured population at any given time. Data are almost totally lacking on the depth of coverage given under individual policies.

Trends in Enrollment, 1940-66

Data on enrollment for hospital care, surgical service, and in-hospital physician visits are available for each year since 1940. Figures on the extent of coverage for the other services were first compiled only a few years ago.

Hospital, surgical, and in-hospital medical protection. The figures in tables 5, 6, and 7 for Blue Cross and Blue Shield have been compiled by the Office of Research and Statistics from data supplied by the Blue Cross Association and the National Association of Blue Shield Plans. The data for insurance companies are estimates com

11 Blue Cross Association, Statistical Bulletin No. 6, December 30, 1965.