NATIONAL CENTER Series 4

For HEALTH STATISTICS Number 7

VITAL and HEALTH STATISTICS

DOCUMENTS AND COMMITTEE REPORTS

use of Vital and Health Recordsin EpidemiologicResearchA Report of the

United States National Committee

on Vital and Health Statistics

An analysis of the changing needs for data in epidemiologic

research in relation to the present vital and health statistics

system with recommendations for use of existing vital and

health records and for developing new data for epidemiologic

studies.

DHEW Publication No. (HSM) 73-1265

Washington, D. C. March 1968

U.S. DEPARTMENT OF

HEALTH, EDUCATION, AND WELFARE Public Health Service

John W. Gardner William H. Stewart

Secretary Surgeon General

Public Health Service Publication No. 1000-Series 4-No. 7

NATIONAL CENTER FOR HEALTH STATISTICS

THEODORE D.WOOLSEY, Director

PHILIP S.LAWRENCE, SC.D., Associate Director

OSWALD K. SAGEN, PH.D.,, Assistant Director for Health Statistics

WALT R. SIMMONS, M.A., Assistant Director for Research and Scientific

ALICE M. WATERHOUSE, M. D., Medical Consultant

JAMES E. ‘KELLY, D. D. S., Dental Advisor

LOUIS R. STOLCIS, M.A.,Executive O//icer

DONALD GREEN, lf@~afio~of/icey

Development

Development

OFFICE OF HEALTH STATISTICS ANALYSIS

IWAOM.MORIYAMA,Ph.D.,Director

DEAN E.KRUEGER, Deputy Director

Public Health Service Publication No. 1000-Series 4-No. 7

Library of Congress Catalog Card Iiurnber 67-62375

FOREWORD

This report, prepared under the auspices of the U.S. National Com-mittee on Vital and Health Statistics considers ways in which vital andhealth statistics systems can better serve the changing need for datain epidemiologic research. These needs arise from the increasing con-cern with chronic noninfectious diseases and the measurement problemsrelated to the nature of these diseases,

Recommendations are made for modifying the content of basic vitaland health records, and for developing new ways of making data fromthese records available for epidemiologic research and other uses.

Robert L. Berg, M.D.ChairmanU.S. National Committee onVital and Health Statistics

...Ill

U.S. NATIONAL COMMITTEE ON VITAL AND HEALTH STATISTICS

Robert L, Berg, M.D., Chairman Herbert E. Klarman, Ph.D.Professor and Chairman, Department of Department of Public Health Administration

Preventive Medicine and Community Health School of Hygiene and Public HealthThe University of Rochester The Johns Hopkins UniversityMedical Center Baltimore, MarylandRochester, New York

Iwao M. Moriyama, Ph. D., Executive Secretary Everett S. Lee, Ph.D.Director, Office of Health Statistics AnalysisNational Center for Health StatisticsPublic Health Service*Washington, D.C.

Donald J. DavidsChief, Records and Statistics SectionColorado State Department of Public HealthDenver, Colorado

William HaenszelChief, Biometry BranchNational Cancer InstituteNational Institutes of HealthPublic Health Service*Bethesdaj Maryland

Clyde V. Kiser, Ph.D.Senior Memker, Technical StaffMilbank Memorial Fund40 Wall StreetNew York, New York

Department of Sociology and AnthropologyUniversity of MassachusettsAmherst, Massachusetts

John R. Philp, M.D.Health OfficerCounty of Orange Health DepartmentP. O. Box 355Santa Ana, California

Donovan J. Thompson, Ph.D.Department of Preventive MedicineSchgol of MedicineUniversity of WashingtonSeattle, Washington

Theodore D. Wmlsey, Ex officioDirector, National Center for Health StatisticsPublic Health Service*Washington, D.C.

SUBCOMMITTEE ON

USE OF VITAL AND HEALTH STATISTICS

Brian MacMahon, M.D., ChairmanProfessor of EpidemiologyHarvard School of Public HealthBoston, Massachusetts

Lillian Guralnick, SecretarylSocial Science Research AnalystHealth Insurance Research BranchDivison of Health Insurance StudiesSocial Security Administration*Washington, D.C.

1. M. Moriyama, Ph. D., Ex officioExecutive SecretaryU.S. National Committee on Vital and Health

StatisticsWashington, D.C.

John Cassel, M.D., M.P.jf.Professor of EpidemiologySchcol of Public HealthUniversity of North CarolinaChapel Hill, North Carolina

Carl L. Erhardt, SC.D., Director2Health Intelligence StatisticsThe City of New York Health Services AdministrationNew York, New York

*Department of Health, Education, and Welfare

IN EPIDEMIOLOGIC RESEARCH

Elmer A. Gardner, M.D., Director3Community Mental Health CenterHealth Sciences CenterTemple UniversityPhiladelphia, Pennsylvania

Robert W, Miller, M.D.Chief, Epidemiology BranchNational Cancer InstituteNational Institutes of HealthPublic Health Service*Bethesda, Maryland

Donald L. Rucknagel, M.D.Department of Human GeneticsUniversity of Michigan Medical SchcdAm Arbor, Michigan

Colitt White, M.D.Professor of BiometryDepartment of Epidemiology and Public HealthSchool of MedicineYale UniversityNew Haven, Connecticut

lWhen appmn“ ted to the Suhcommittse, Miss Guralnick was a Statistician, Office of Health Statistics Analysis, National Center for Health Sta-tistics, Public Health Service, Department of Health, Education, and Welfare, Wasbingtcm, D.C.

%fntil July 1, 1966, Dr. Erhardt was Associate Director, Office of Research, City of New York Deportment of Health.

3When appointsd to the Subcommittee, Dr. Gardner was Assistant Professor and Director, Division of Preventive Psyohia@, University of

Rochester School of Medicine and Dentistty, Rochester, New York.

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CONTENTSPage

Foreword ------------------------------------------------------------

U.S. National Committee on Vital and Health Statistics --------------------

Subcommittee on Use of Vital and Health Statistics in EpidemiologicResearch -----------------------------------------------------------

Introduction ----------------------------------------------------------

Need for Review ------------------------------------------------------

Procedure ------------------------------------------------------------

Findings and Recommendations -----------------------------------------

Access to Vital and Health Records ----------------------------------Record Linkage --------------------------------------------------The Unique Number ----------------------------------------------Ascertainment of Death -------------------------------------------Followup --------------------------------------------------------

Information on Vital and Health Records ------------------------------Cause of Death --------------------------------------------------Congenital Malformations -----------------------------------------Other Items -----------------------------------------------------

Development of Other Resources -------------------------------------

Summary of Recommendations ------------------------------------------

Appendix I. Selected Bibliography on Record Linkage -------------------

Appendix II. The Underlying Cause Concept ----------------------------

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IN THIS REPORT the changing needs for data in epidemiolo~”c re-search are examined in relation to the pvesent vital and health statis-tics systems.

The ascendancy of chronic noninfectious diseases as major causes ofmovbidity and mortality requires new types ofdu$a and changes of em-phasis in existing types of data. New measurement problems are oftenencountered in these diseases, in which onset may be insidious, pro.gression slow, and the interval between causes and effects long.

Each source of vital and health statistics is examined in terms of theinformation requested on the basic record, the present means of accessto the data on the vecord, and the tabulations now being prepared by theNational Centev for Health Statistics.

Linkage of vcwious vital and health records is seen as a means of in-creasing their sepavate valwe, and fuvther exploitation of this device isrecommended. Use of some ynivenal identity numbev fov this purposeshould be explored along with the possibility of assigning such numbersat bivth,

A National Death Index would be a great- asset in epidemiologic re-search. The National Center for Health Statistics is urged to explorethe technical pvoblems in establishing this vesouvce. Extension of thescope of patholo~”cal conditions vecorded on death certificates beyondthose contributing to death should be considered.

Other recommendations are made for development of vital records in-formation on congenital ma~ormations and for inclusion of a sample ofnewbovn infants in the Health Examination Survey.

vi

USE OF VITAL AND HEALTH RECORDS INEPIDEMIOLOGIC RESEARCH

t!~~~i% some t~ths, ad not commonly-believed opinions, to

arise ~?om my meditations upon these neglected papevs (the Bills ofMortality), I proceeded j%rther, to consider what benefit the knowledgeof the same would hying to the world; that I might not engage myself inidle, and useless speculations, but . . . present the world with some realfYuit Jrom those ayyie blossoms.”

John G~aunt, 1662

INTRODUCTION

The practice of epidemiology, or indeed ofpublic health, would today be inconceivable with-out access to vital and health records and the tabu-lations routinely assembled from them. The dataobtained by Graunt’s “antient matron” searchershave been replaced by legally required certificatesof birth and death. These documents, and thebreadth of their application, have changed re-markably in the last 50 years, and today theyprobably constitute the single most important re-source of epidemiologic investigation. In addition,entirely new sources of health statistics have beendeveloped, notable among these, in the UnitedStates, being the several programs of the NationalHealth Survey.

With respect to epidemiologic purposes, vitaland health records serve the following functions:

1. As source data for the measurement of theincidence and prevalence of disease.These measurements serve administra-tive as well as epidemiologic purposes,Because of the limitations of diagnosticinformation derived from certificates ofbirth and death, it is to this general pur-pose of providing source data that mostof the newly introduced types of healthstatistics have been addressed.

2.

3.

4.

5.,

For comparison of disease rates in dif-ferent populations, indifferent parts of thesame population, and in similar groupsover a period of time, in order to develophypotheses regarding the etiology of dis-ease. Studies over time may also serveto evaluate the effectiveness of preven-tive or therapeutic measures.

For identification of groups of people athigh risk of particular diseases. Suchgroups may be of significance in diseasecontrol or they may be particularly suit-able for studies of etiology and therapy.

As the starting point for “follow-back”studies in which a series of cases withparticular characteristics (e.g., dyingfrom a particular disease) is identifiedfrom the primary source (in this instance,the death certificate) and supplementaryinformation is sought from other sources(e.g., the certifying physician) relevant toetiology or other subjects of interest.

As the end point for studies in which sub-sets of the population are selected becauseof their unusual characteristics or en-

vironmental exposures and followed toidentify diseases or other outcomes sus-pected of being related to the selectedfactors.

1

Erhardt 1 and Moriyama~ have recently com-piled some examples of the ways in which vitalrecords are being utilized for epidemiologicresearch. Major projects in this country that aredependent on vital records include the extensiveseries of studies of veterans carried on by theFollow-Up Agency of the National Academy ofSciences, National Research Council, the large-scale studies of the effects of smoking on healthby the National Heart Institute and the AmericanCancer Society, the followup programs of regis-tries of cancer and other specific diseases,, anda great many smaller scale studies aimed atspecific problems.

It is difficult to assess the extent of epi-demiologic use of the statistics published inVital Statistics of the United States or in thereports from the National Health Survey. Re-ference to any journal of epidemiology or publichealth will yield examples of such uses, but ex-tensive use is also made of them by individualinvestigators in searching for ideas and in pre-liminary testing of hypotheses-activities thatlargely pass unrecorded.

NEED FOR REVIEW

The emphasis of epidemiologic investigationhas shifted markedly in the last two decades. Adecline in interest in the infectious diseases andincrease in concern with the noninfectious dis-eases have resulted from the change in relativeimportance of these categories of disease inmany parts of the world, including the UnitedStates. It is also recognized that, although majortasks still remain in the improvement of controlover the infectious diseases, the contribution ofepidemiology to the development of controlmethods is largely past —new advances are being”made predominantly as the result of work in theexperimental laboratory and. through the betterapplication of existing knowledge. On the otherhand, the identification of cigarette smoking asthe major cause of this centuryis epidemic oflung cancer has clearly demonstrated the po-

lErhardt, C. L. Vital records are useful. Harvard, Pub.

Health Alumni Bull. 227-11, 1965.

2Moriyama, I. M.: Use of vital records for epidemiologicalresearch. J. Chronic W?. 17: 889-897, 1964.

tential contribution of epidemiologic research. atthe present stage of knowledge of those chronicdiseases that now constitute the predominanthealth problems in this country.

This shift in emphasis of epidemiologic in-vestigation has required great changes in method-ology, if not in philosophy. New or newly em-phasized methods are required to deal withproblems such as:

1.

2.

3.

4.

5.

Detection of causal associations in whichdecades or generations may lapse betweencause and effect.

Measurement of existence and stage ofdiseases whose onset and progression areinsidious and often unknown to the patientfor many years.

Description of demographic distribution ofconditions of low mortality for which thequality of medical diagnosis may varymarkedly between populations and popu-lation subgroups.

Scientific and administrative problems ofcohort studies that require large numbersand long-term followup.

Detection of clustering of disease in timeor place at a much lower level of intensitythan that observed in frank infections.

With these types of problems in minfi, “it hasseemed useful to review existing health statis-tics and their sources to determine whether theyshould and could be modified to better serveepidemiologic needs.

The review has been further stimulated byrecognition of the enormous increase that hasoccurred and will continue in the technical feasi-bility of data reduction, retrieval, and analysison a large scale. The potential of this improvedtechnology may be unrealized if the basic recordsare not appropriately modified.

In the past, the nature of health statisticsand the usefulness of vital records have &enlimited by the fact that the records were es-tablished and continued for legal rather thanhealth purposes. In the last 50 years, however,there has been increasing acceptance of the useof vital records for public health and scientificpurposes. There is, rherefore, a good prospect

that the demonstration of significant epidemio-logic needs will be influential in producingchanges or applications in vital records andstatistics. While most of the information thathas been added to vital records and the newsources that have developed have been based ona request for voluntary response, rather than asa legal requirement, there is no evidence thatquality or completeness of information has beencompromised on this account.

PROCEDURE

The subcommittee has limited its considera-tion to the uses of health records and statistics ininvestigating the etiology of disease. Althoughthis may imply a rather narrow definition of“epidemiologic uses, “ it embraces the most im-portant use of epidemiologic data. Other sub-committees of the National Committee have, ofcourse, keen concerned with medical care, de-mography, and other areas in which “epi-demiologic” data have application.

The committee has reviewed the standardcertificates of birth, death, fetal death, marriageand divorce, now in the final stages of a de-cennial revision, as well as the tabulations regu-larly developed from these sources and publishedin Vital Statistics of the United States. Programs,data forms, and reports of the three main com-ponents of the National Health SurveJ –The HealthInterview Survey, the Health Examination Survey,and the Health Records Survey— were considered.The purposes of and current activities in specialdisease registries, record linkage, and geneticuses of linked vital records were reviewed.

The subcommittee did not deal with im-portant issues of confidentiality of vital andhealth records and protection of the privacy ofindividuals. While these issues underlie any useof vital records for epidemiologic purposes andmight be important in the implementation ofseveral of its recommendations, the subcom-mittee did not consider itself constituted withthe legal and other representation that would berequired for a meaningful discussion of the issues.It should ke pointed out, however, that legal andprocedural safeguards against the misuse of vitalrecord information have been part of the operationof Federal and State statistical systems for manyyears, and that these safeguards have been phe-nomenally successful. The distinction between

the use and dissemination of data on individualsas individuals and their use for describing thecharacteristics of groups without the identifi-cation of individuals has become widely recog-nized and accepted as a basis for statistical andepidemiological use of c, mfidential records.Computers now provide new and even more ef-fective techniques for protection against the tpis-use of confidential information.

The subcommittee did not take up the ques-tion of infectious disease reporting, the nationalcomponent of which is now the responsibility ofthe National Communicable Disease Center(NCDC), Atlanta, Ga. However, it is believed thata review of this area would be useful, and theNational Committee might consider the establish-ment of a subcommittee with special competencein infectious disease and with representation fromNCDC and State Health Departments to reviewthis field.

With respect to each of the types of recordsreviewed, the subcommittee considered (a) the in-formation existent, or requested, on the basic rec-ord, (b) the tabulation now prepared from thisinformation by the National Center for Health Sta-tistics (NCHS), and (c) the existing means of ac-cess to the information contained on the records.

By far the most important gap betweenexisting and potential usefulness seemed to liein connection with item c, access to records.Since the major recommendations of the sub-committee are in this area, it will be consideredfirst.

FINDINGS AND RECOMMENDATIONS

Access to Vital and HealthRecords

The problem of access to vital records hasbecome acute with the revolutionary changes indata processing techniques already referred to.The potential for record utilization has been ex-panded almost beyond limit, provided the recordsand their storage are in such forms as permitmachine access. Aggravating the problem is thefragmentation of the U.S. vital record systeminto more than 50 politically, geographically, andadministratively independent systems. The effectsof this fragmentation are especially evident instudies th~ require that people be followed over

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long periods of time, as is usually the case ininvestigations of the etiology of chronic diseases.

Two particularly urgent needs are apparent:(a) methods that will improve our ability to “link”records pertaining to the same person or family,and (b) facilities to improve our ability to tracedeath records of persons enrolled in investiga-tions.

Record Linkage

The potential of the information to be ob-tained by linkage of records is obvious. Thelinkage of records pertaining to an individualallows the correlation of events and circumstancesof his life extending over the long periods as-sociated with the incubation and development ofchronic disease. The linkage of records per-taining to members of the same family allowsstudies of the genetic determinants of disease aswell as the familial environment. No one seriouslyquestions the premise that the linkage of healthrecords of as many varieties as possible wouldbe of great value for patient care and adminis-trative purposes as well as for the purposes ofetiologic investigations.

The practical aspects of the record linkageproblem are less clear. A number of experi-mental record linkage systems have been set upin recent years, and a bibliography of relevantpublications is given in Appendix I. Basic ques-tions still at issue are (a) what identifying in-formation most accurately allows linkage ofrecords of the same individual or family, (b) whatrecords can be linked with the greatest profit interms of derived information, and (c) ‘what is themost appropriate population size to ke covered.Unfortunately, the answers to these questions arenot generalizable to all times or all places, andalthough some of them have keen answered forinvestigations of particular problems in particularplaces, it appears that available information isinsufficient to recommend inauguration of anyparticular record linkage system in the UnitedStates as part of routine record procedures.

Two general recommendations do seem ap-propriate however. First, exploration of individ-ual and family record linkage should continue tobe pressed as a high priority research area toidentify which linkages are likely to be most prof-itable and which methods most efficient. Second,

the basic records themselves should already bein process of modification so that (a) recordlinkage for the purpose of specific short-termstudies, whether performed clerically or elec-tronically, is facilitated and improved in ac-curacy, and (b) record systems are prepared forthe incorporation of routine machine linkagewhen the time comes. Perhaps the most im-portant single component of this modificationwould be the acceptance and wider use of theconcept of a unique number to identify each in-dividual in a population.

“The Unique Number

The idea that each individual would have aunique number and that this number would identifyall his health (and other) records is an old one,The advantages of such a procedure for recordlinkage are obvious. The widening use of theSocial Security number in the United States putsthe concept within the realm of feasibility fora large proportion of the population, perhaps forthe first time. Several other numbering systemshave been proposed, and even tried. A uniquebirth certificate numbering system, begun in1947, has subsequently been dropped in manyareas, presumably because of lack of use.

The wider the use of a particular number,the greater is the amount of information that canbe linked. At the same time, the more frequentlyan individual is asked for that number the morelikely he is to remember it correctly or have itavailable, which again encourages its use forother purposes. Thus, there is a circular effectoperating-in favor of the more widespread number-ing system. This consideration argues over-whelmingly for the adoption of the Social Securitynumber as the unique identifying number forhealth record purposes. If there was doubt aboutthis previously, it was dispelled by the imple-mentation of the Medicare program, in which theSocial Security number is the basic identifyingdevice.

The Social Security number is not ideal, Aproportion of the population still has no number;a person may, by request, have more than onenumber; numbers are not usually assigned untilwage earning begins; the lack of any apparentpattern to the assigned number (i.e., a person

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cannot directly relate his number to his birthdate or any other readily remembered set offigures) makes for frequent errors in recordingand transcribing. Some of these problems willdecrease as time passes and use of the numbersspreads. Others may be mitigated by deliberateefforts.

In the latter context, for example, it is notedthat NCHS and representatives of State HealthDepartments are planning to confer with theSocial Security Administration (SSA) to explorethe possibility that a number assigned to an in-dividual at birth by the State Health Department(from a list previously supplied by SSA) couldlater become the Social Security number whenthe individual makes application for assignmentof a number.

Hospitals should be asked to incorporateSocial Security numbers as part of their basicidentifying information. (Presumably, this willin any event be necessary for Medicare patient s.)They should be asked to explore the feasibilityof the use of the Social Security number in placeof their own record numbering system. Thiswould greatly improve access to records of aparticular patient identified by means of hisSocial Security number in some other context.

The U.S. Standard Certificate of Death nowcontains a place for the Social Security number.The States are urged to retain this item in theirown certificates and to press for its completionin all possible instances. Whether or not it sub-sequently becomes possible to assign a “SocialSecurity number !! at birth, it would be of great

value to incorporate Social Security numbers ofboth parents on the Certificate of Live Birth.Family record linkages would be enormouslyfacilitated by this procedure.

Ascertainment of Death

U.S. death certificates contain a considerableamount of information regarding the decedent, andthe presumed cause of his death. The quality ofthe information is high and the completeness ofregistration is excellent. These certificates con-stitute a most valuable source of information forepidemiologic studies,

The major problem arises in locating thedeath certificate of a specific individual unless

the date and place of his death are known withaccuracy. The registration system is centralizedonly with respect to certain advisory functionsand the preparation of national statistical tabu-lations. After the national statistical tabulationshave been prepared, the centralized copies of thebasic records are discarded. To locate the deathcertificate of a person whose place of death is notknown might involve separate searches in morethan 50 different States and cities. There is con-siderable variation across the country in theease with which searches of these archives canbe conducted. In addition, there is an under-standable reluctance on the part of some Regis-trars to undertake searches for certificateswhich may not exist in their archives. It shouldbe noted that, in some jurisdictions, while thecost of the search is borne by the Registrar’soffice, the reimbursement goes directly into theState treasury and does not compensate the Reg-istrar’s office for the additional labor involved.

As only one example of the type of problemthat this fragmentation can provoke, it may bepointed out that in a current study of the mortalityamong steelworkers undertaken by the NationalCancer Institute, more than 30 clerical steps areinvolved in tracing the subjects from employmentto death. In addition to the size of the task in-volved in tracing deaths, there is also a problemwith completeness, since it is, in practice, neverpractical to search for untraced cases in all 50jurisdictions. Searches are usually restricted totwo or three States with the highest rates of im-migration from the area of the study.

The idea of a National Death Index locatedin the National Center for Health Statistics hasbeen discussed, more or less casually, fromtime to time in the past. The index would permitidentification of the fact, place and date of death,and, probably, State death certificate number.Access to information on the death certificatesthemselves would, as now, be through individualState registries.

It is believed that the mounting volume ofstudies of the chronic diseases alone makes theestablishment of such as index an urgent ne-cessity. There are, in addition, needs for suchan index in connection with Medicare, and othermedical care and commercial purposes. The costof the index could be justified entirely by its

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epidemiologic uses, but the additional medicalcare and commercial uses ‘appear to eliminatecost as a serious deterrent.

In epidemiology, the index would be usedprimarily for studies of prognosis or cause ofdeath among persons having particular diseasesor undergoing particular exposure, for example:

1.

2.

3.

4.

5.

Selected occupations, e.g., steelworkers,the rubber industry, hard-rock and ura-nium miners, smelters, etc.

Professional societies whose membershave unusual laboratory exposure, e.g.,American Chemical Society, AmericanSociety of Immunologists.

Groups undergoing health status evalua-tions (as predictors of longevity or causesof death) e.g., participants in the NationalHealth Survey, Kaiser-Permanente mul-tiphasic examinations, studies of infantdevelopment and health status, executivehealth (preventive maintenance) pro-grams, and the American Cancer Society’sstudy of more than 1 million persons.

Other suspected special risk groups, e.g.,children who received SV 40 or othercontaminated vaccines or drugs, personsexposed to ionizing radiation, blooddonors, cases of accidental poisoning,etc.

Members of special disease registries—cancer, mental illness, congenital mal-formation,

It is therefore recommended, that a NationulDeath Index be established. Problems that re-quire detailed technical study include the amountand nature of information that will be required foraccurate identification, cost of the index, and theextent to which this cost can be met by com-mercial uses.

Followup

in some studies it is sufficient to identifythe dead members of the study group--membersnot so identified being assumed to be alive. How-ever, when death ascertainment is known to be

incomplete, or when pathologic end points shortof death are being studied, it is usually necessaryto trace individuals over periods of years ordecades.

In this country, in the presence of con-siderable migration and the absence of cent inuouspopulation registration, a national health serviceor other national identification system, such afollowup can be extremely difficult. Nevertheless,there are numerous resources and methods thatcan be utilized. Many workers appear to be un-aware of the range and potential of these re-sources. In connection with its own researchprogram the Division of Radiological Health(DRH), USPHS, prepared in 1962 a roster offollowup facilities.q More than 30 sources aredescribed, together with the legal basis on whichthey may be utilized and the usual proceduresinvolved. It is believed that it would be mostuseful to make such a document readily availablethrough publication, and it is recommended thatNCHS arrange for the preparation and publicationof a revised version of the DRH manuscript or anewly prepared document with similar intent.Costs of various procedures should be included.

Information on Vital and HealthRecords

Having in mind the undesirability of burden-ing routinely prepared documents with informationrequired only for ad hac and limited purposes,there are few recommendations to be made re-garding the content of existing vital and healthrecords. However, some areas of concern wereidentified,

Cause of Death

The present standard certificate of deathrestricts information on pathologic conditionsexisting in the decedent to those which the certi-fying physician considered as contributing to thedeath. In fact, however, with many chronic condi -

3Staff of the Cooperative Thyrotoxicosis Therapy Follow.Up Study: Resources forLocating Patients. Division of Radio.logical Health, U.S. Public Health Service, 1962. (mimeo.graphed)

t ions it may be impossible to determine in individ-ual cases whether or not an existent conditioncontributed to the death; such a determination

may be possible only in terms of statisticalprobability based on comparison of mortalityrates in groups of persons with and without thecondition, In many instances, therefore, selectionof pathologic conditions to appear on the certifi-cate is arbitrary and inconsistent. A memoran-dum on this matter is reproduced in Appendix IIas a basis for discussion.

The matter, while clearly a theoreticalproblem, did not appear of great practical mo-ment so long as statistical tabulations, and,generally speaking, access to certificates,were on the basis of a single pathologic conditionselected as the “underlying” cause. This singleselection made quite obvious the arbitrary natureof the information presented and the necessityto restrict the use of diagnostic information topathologic conditions likely to be selected as theunderlying cause if they were present.

However, NCHS is now committed to earlyinitiation of a program of coding and tabulatingmultiple causes of death listed on individualcertificates. It then becomes much more crucialwhich conditions are included on and which omittedfrom the certificate, From two points of view--(a) for investigating in statistical terms whichconditions do in fact contribute to death and inwhat degree, and (b) improving the death certifi-cate as a general research tool— it seems im-portant to shift the emphasis in certification fromconditions supposedly contributing to death toconditions present at the time of death, or ofwhich residua are present at the time of death.

How such additional information might bestbe collected has not been evaluated. Thus, indesigning a possible Part III of the cause ofdeath question on the death certificate, seekinginformation on other significant conditions pres-ent, . it is not clear whether more completecertification would be obtained by means of anopen- ended question or by a checklist of condi-tions such as diabetes, hypertension, congenitalmalformation, and so on. Such questions may beapproachable through follow- back studies start -ing from current certificates, and it is suggestedthat such studies be undertaken as a basis for

specific proposals for the next revision of thestandard certificate.

Congenital Malformations

As other causes decline, the congenital mal-formations become responsible for an increasingproportion of mortality and morbidity in infancyand childhood. Because certain forms of mal-formation have been clearly shown to be pre-ventable, and because of the relatively shortinterval between cause and effect, this categoryof diseases is a prime target for investigativeeffort. Birth certificates can provide a majorresource for this effort by providing access to(1) very large numbers of cases of common mal-formations, (2) large numbers of cases of com-mon malformations with characteristics of partic-ular value, e.g., being a twin. (3) series ofcases of malformations of such rarity that seriescannot be assembled from clinical sources, and(4) population-based series that can be used toinvestigate geographic and temporal clustering.

Birth certificates can never be expected toprovide a complete ascertainment of malfor-mations—partly because of the impossibility ofdefining a malformation. However, descriptivefeatures make it quite evident that differentetiologic factors are operative in different cate-gories of malformation, and, in some instances,within a single diagnostic category of malfor-mation. Birth certificates will be a useful re-source even if their information is limited to

‘those major, externally evident, anomalies whichcould be expected to be fully reported in areasonably competent system.

It is to be hoped, therefore, that all Stateswill retain the malformation item proposed onthe standard live birth certificate, and makeefforts to improve reporting of this item. Withrespect to the maintenance of surveillance ofmalformation reporting, in order to detect geo-graphic or temporal clustering at an early stage,it is recommended that a comparison k made be-tween reporting on birth certificates and systems,such as have been set up in New Jersey andBritish Columbia, that are based on reportingindependent of the birth certificate.

It is further recommended that considerationbe given to the possibility of examination of a

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nationally selected sample of newborn infants(including late fetal deaths) as one of the cyclesof the Health Examination Survey. With respectto congenital malformation specifically, such asurvey would provide estimates of the prevalenceof congenital malformations detectable at birth—heretofore unavailable except with respect to

the patients of a few highly specialized hospitals—and a standard against which to evaluate othermeans of estimating malformation rates, Becauseof the special problems of conducting examina-tions immediately after birth, such a surveywould require different sampling proceduresfrom those that have been used so far in theHealth Examination Survey. However, samplingof maternity facilities and of blocks of timewithin such facilities (rather than direct samplingof individuals born) would seem to provide arelatively simple method for assembling a repre-sentative national sample of births.

Other Items

Level of education of parents has replacedoccupation on the standard certificates of livebirth and fetal death. The replacement resultsfrom the difficulty of interpreting and codingthe occupation item, and belief that, as an indexof social class (which is the main purpose of theoccupation item), education is equally valid, Inview of the very limited use of occupation asrecorded on death certificates, an attempt mightalso be made to collect education data on deathcertificates in selected areas. The greater dif -ficulty of obtaining education data on decedents,as contrasted with parents, is recognized, and inthe evaluation phase the item should probably besought as a supplement to, rather than replace-ment for, information on occupation.

In many studies of the effects of social andpsychologic stress it would be advantageous tohave the names (rather than simply the number)of the children as an item on the certificate ofdivorce. It is understood, however, that there isa reluctance on the part of Registrars to pressfor this item.

Development

of Other Resources

It seems worthwhile to identify two resourcesthat do not appear to have been utilized to theirfullest potential for epidemiologic investigation,although there are no specific recommendationsas to how their utilization might be increased,

The first consists of the records of deathscoming under the purview of the medical ex-aminer. The medical examiners’ investigationsof such deaths are detailed and the records arepublic. Medical examiners in general appear tobe favorably disposed to the utilization of therecords for scientific investigation, and, in someinstances, have initiated epidemiologic investi-gations based on their material. The recordsoffer extensive possibilities for analysis alone,or as the starting point for investigations in whichadditional information is sought.

The second resource consists of the recordsof health insurance schemes. The value of suchrecords is demonstrated by the series of reportsbased on the experience of the Health InsurancePlan (HIP) of Greater New York. While it is truethat HIP incorporates medical care as well asan insurance program, essentially similar rec-ords are usually required as the basis for pay-ment even when the medical service is not per-formed by the insuring company. Remarkablylittle use has been made, for example, of thevoluminous material that must exist in BlueCross- Blue Shield plans relevant to studies ofthe familial clustering of disease, the associationof diseases in individuals, and ‘the natural historyof chronic diseases.

Lastly, in connection with the major pro-grams of medical care now being initiated—notably Medicare, the Title 19 provisions ofMedicare as they relate to children, and theheart-cancer-stroke and community mental healthcenters—it is hoped that adequate statistical andepidemiologic consultation will be obtained atthis early stage to ensure the ultimate usefulnessof the medical records.

SUMMARY OF RECOMMENDATIONS

1,

2.

3.

4.

5.

Linkage of various vital and health rec-ords should continue to be explored as ahigh priority research area, to identifywhich linkages are likely to be mostprofitable and which methods most ef-ficient.

The Social Security number should beaccepted as the most practical numeri-cal identification of individuals, and in-corporated into all vital and health rec-ords, Where possible, the Social Securitynumber should become the actual identi-fication number for the specific record ofthe individual. Hospitals should be askedto consider this last possibility.

NCHS, representatives of State HealthDepartments, and the Social SecurityAdministration should explore the possi-bility of assigning a Social Security num-ber to dn individual at birth. This recom-mendation supposes that the Social Se-curit y Administration is itself not alreadyconsidering the use of a birth numberingsystem for its own purposes.

Social Security numbers of parents shouldbe added to the certificates of live birthand fetal death.

Because of the great epidemiologic use-fulness of a National Death Index, NCHSshould explore with some urgency thetechnical problems involved in the es-tablishment of such a resource. Apartfrom estimates of cost and the extent towhich this would be mitigated by com-mercial use, there is need for information

6.

7.

8.

9.

on the amount and nature of the infor-mation required to identify decedents,and the computer technology most ap-propriate to such an extensive operation.It should be stressed that an index ismeant, not a repository for the death cer-tificates themselves.

A document should be prepared and pub-lished for the assistance of investigatorsin followup studies, along the lines of thatprepared for their own staff by the Divi-sion of Radiological Health. Sources offollowup, legal bases, usual procedures,and costs should be included.

The basis for inclusion of pathologic con-ditions on the death certificate may needto be extended beyond the present re-striction to conditions presumed to havecontributed to the death. Information mightbe sought on all significant conditionspresent at the time of death, or of whichsignificant residua are present at thetime of death. The best way of obtainingthis information should be sought infollow- back studies based on currentcertificates in preparation for the nextrevision of the standard certificate.

Efforts should be made to extend, im-prove, and utilize information on con-genital malformations reported on vitalrecords, particularly the birth certificate.

Consideration should be given to thepossibility of examination of a nationalsample of newborn infants (including fetaldeaths) as one of the cycles of the HealthExamination Survey.

00

9

APPENDIX I

SELECTED BIBLIOGRAPHY ON RECORD LINKAGE

Acheson, E. D.: The oxford Record Linkage Study, Reporton the Second Year’s Operations. Oxford Regional Hospital

Board. Oxford, England 1963.

Acheson, E. D.: The Oxford Record Linkage Study, a re-view of the method with some preliminary results. F’rvc.Roy.Soc.Med. 57:11, 1964.

Acheson, E. D.: The Oxford Record Linkage Study, a cen-tral file of morbidity. &it. J, Preo. &SocW Med. 18:8, Jan. 1964.

Acheson, E. D., and Evans, J. G.: The Oxford Record Link-age Study. Biometrics 2:367, 1963.

Acheson, E. D., Truelove, S. C., and Witts, L. J.: Nationalepidemiology. Brit.M.J. 1:668, 1961.

Bahn, A. K.: Methodological study of population of oubpatient psychiatric clinics, Maryland 1958-59. Public Health

Monograph No. 65. PHS Pub. No. 821. Washington, D.C., 1961.

Bahn, A. K.: The development of an effective statisticalsystem in mental illness. Arn.J.Psychiat. 116:798, 1960.

Bahn, A. K.: Person matching by electronic methods.Communications of the Association for Computing Machinery5:404, 1962.

Babn, .4. K., and Bahn, R.: Considerationsin using socialsecurity numbers on birth certificates for research purpoees.Pub. HeaZth Rep. 79:937, 1964.

National Office of Vital Statistics: Some aspects of vitalstatistics registration in Canada, by A. E. .Bailey. VitalStatiez!ice-SpeciaZ Rep&k Vol. 23, No. 22. Public HealthService. Washington, D.C., 1947. pp. 252-61.

National Center for Health Statistics: Summary report onTennessee’s “Record of Events,” by M, R, Baird, and E. H.Halpin. The Public Health Conference on Records and StG-tie tics, PHS Dec. No. 473. Public Health Service. Washing-ton, D.C., Dec. 1959

Central Bureau of Statistics: Population changes 1961.Official Statistics of Sweden (Population and Vital Statis-tics) Stockholm, 1963.

Davidson, L.: Retrieval of mispelled names in an airlinepassenger records system. Communications of the i4ssoc&ation for Compu$ing Machiney. 5:169, 1962.

Dunn, H. L.: Record linkage. Am. J. Pwb.Heatth. 36:1412,1946.

Dunn, H. L.: A national identity registration system tosynthesize social statistics. Estadiatica, Journal of the InterAmerican Statistical htstitute 11:605, Sept. 1953.

Harris, R.: Letter to Dr. Councell dated Mar. 8, 1965.

Kennedy, J. M.: Linkage of birth and marriage recordsusing a digital computer. Atomic Energy of Canada Ltd.,Report No. 1258, Chalk River, Ontario, 1961. p. 18.

Kennedy, J. M.: The use of a digital computer for recordlinkage. Proceeding of the Seminar on the Uee of Vital andHealth Statistics for Genetic and Radiation Studies, 1962,pp. 155-159.

Kennedy, J. M., Newcombe, H. B., Okazaki, E. A., andSmith, M. E.: List processing methode for organizing filee oflinked records. Atomic Energy of Canada Ltd., Report No. 2078,1964.

Kjelsberg, M., and Metzner, H.: Record system used in theTecumseh Community Health Study. Personal communication.

Marshall, J. T.: Canada’s national vital statistics index.Population Strtdies 1(2):204, Sept. 1947. (Printed in GreatBritain.)

Masi, A. T., Sartwell, P. E., and Shulman, L. E.: The useof record linkage to determine familial occurrence of diseaeefromhospital records (Haehimoto’s disease). Am.J.Pub.Health54(11): 1887-1894, NOV. 1964.

McKeown, T. and others:. Session VII, panel discussion,session on epidemiological studiee. Second international Con-ference on Congenital Malformations. The International MedicalCongress, Ltd., New York, 1964. pp. 341-351.

Minet, P. L.: Fertilitd pr~coce d’une cohorte de mariagesclans une province canadienne. Biology Branch. Atomio Energyof Canada Ltd. Basel 14:186-196. Chalk River, Ontario, 1964.

National Center for Health Statistics: “Studygroup on recordlinkage. The Public Health Conference on Records and Statis-tics, PHS Dec. No. 603. Public Health Service. Washington,U.S. Government Printing Office, Nov. 1964.

National Centsr for Health ”Statistics: Planning session forstudy group on record linkage. The PUWC Health Conferenceon Records and Statistics, PHS Dec. No. 603.1. Public HealthService. Washington. U.S. Government Printing Office, Jan.1965.

Newcombe, H. B.: Detection of genetic trends in public

health. E/feet of Radiation on Human He?edity. World Health

Organization, Geneva, 1957. pp. 157-168.

Newcombe, H. B.: Record linkage as a means of studyingthe somatic effects of low doses of radiation. Science 130:

994.959, 1959.

Newcombe, H. B.: Population genetics, population records.

hlethodology in Human Genetics. Holden-Day, Inc., 1962. pp.

92.113.

Newcombe H. B.: Untapped knowledge of human populations.

Transactions of the Royal Society of Canada. Vol. LVI, Series

III, Section 111, June 1962. pp. 173-180.

Newcombe, H. B.: Risk of fetal death to mothers of differ-

wrt ABO and RH blood types. Am. J. Human Genet. 15(4):

449-464, Dec. 1963.

Newcornbe, H. B.: Pedigrees for population studies, a pro-

gress report. Cold Spring Harbor Symposia on QuantitativeBiology, 29:21, 1964. ‘

Newcombe, H. B.: Panel discussion, session on epidemio-

logical studies. Second International Conference on CongenitalMalformations. The International Medical Congress, Ltd., New

York, 1964. pp. 345-349.

Newcombe, H. B.: Environmental versus genetic interpre-

tations of birth.order effects. Eugenios Quarterly, Nov. 1964.p. 36.

Nmvcombe, H. B.: Screening for effects of maternal age

and birth order, in a register of handicapped children. Ann.Human Genet. 27:367-382. London, 1964.

Newcombe, H. B.: Use of vital statistic. United NationsWorld Population Conference, Belgrade, Yugoslavia, Aug. 30to Sept. 10, 1965.

Newcombe, H. B., Axford, S. J., and James, A. P.: A plan

for the study of fertility of relatives of children euffering from

hereditary rind other defects. Atomic Energy of Canada Ltd.,Report No. 511, Nov. 1957. p. 50.

Newcombe, H. B., James, A. P., and Axford, S. J.: Familylinkage of vi tef and health recorde. Atomic Energy of Canada

Ltd., Report No, 470. Chalk River, Ontario, July 1957. (Re-printed Aug. 1961 and May 1964.)

Newcombe, H. B., and Kennedy, J. M.: Record linkage,

reeking maximum use of tbe discriminating power of identify-

ing i~formation. Communications of the Association for Com-puting Machinery 5(11):563-566,1962.

Newcombe, H. B., and Kennedy, J. h!.: Demographic analy-sis and computer programs. United Nations World Population

Conference, Belgrade, Yugoslavia, Aug. 30 to Sept. 10, 1965.

Newcombe, H. B., Kennedy, J. M., Axford, S. J., and JamesA. P.: Automatic linkage of vital records. Science 130(3381):

954-959, Oct. 1959.

Newcombe, H. B., and Rbynas, P. O. W.: The cost of in-dividual follow-up studies of large populations. Proceedingsof the International Population Conference- Paper No. 16. (Re-

printed as Atomic Ener~ of Canada Ltd., Report No. 1255,

Sept. 1961. p. 8.)

Newcombe, H. B., and Rhynas, P.O. W,: Family linkageofpopulation records. On the Use of VitaJrznd Health Statis-tics fo? Genetic and Radiation St&ies. United Nations Pub.,Sales No. 61. XVII(8) :135-154, 1962.

Newcombe, H. B., and Rhynas, P.O. W.: Child spacing

following stillbirth and infant death. Eugenics QuarteT?y 9(l):25-35, Mar. 1962.

Newcombe, H. B., and Tavendale, O. G.: Effectsof father’sageontherisk ofchildhandicap or death. -4m.J.Human@~e~.17(2):163-178, 1965.

National Office of Vital Statistics: A coordinated system

of vital records and statistics, the need for coordination, byH. L. Dunn. Public Health Service. Washington, D. C., JUly

1953.

Phillips, W., Jr., and Bahn, A. K.: Experience with corn-puter matcbingby names. Proceedings of the Som.al Statis-

tics Sections, American Statistical Asso&ation, 1963.

Phillips, W., Jr., Bahn, A. K., and Miyasaki, M.: Person-matching hyelectronic metbods. Communications of the Asso-ciation foT Computing Machiney 5:404, 1962.

Phillips, W., Jr., and Gorwitz, K., and Bahn, A. K.: Elec-

tronic maintenance of case registers. Pub. Health Rep. 77:503, 1962.

Schwartz, E. E.: Some observations on tbe Canadian fami-ly allowances program. The Social Serv4ce Review Vol. XX,

No. 4. Dec. 1946.

Statistical Commission: Twelfth session, Item 9 of theprovisional agenda E/CN/3/293. United Nations Economic

and SociaJ Council. Feb. 7, 1962. p. 38.

Vinge, Margit, Head, Documentation Unit, Central Bureau

of Statistics, Stockholm. Letter dated Mar. 9, 1965, tn LouisR. Stolcis with attachments.

000

11

APPENDIX II

THE UNDERLYING CAUSE CONCEPT

At the November 1961 Geneva meeting of theSubcommittee on Classification of Diseases ofthe Expert Committee on Health Statistics, it wassuggested that the “concept of underlying causemight be reexamined to see if a more satisfactoryconceptual basis for classifying causes of deathcould not be developed.” The concept can be re-viewed in the light of uses made of informationobtained on death certificates, and from theviewpoint of the data available for decedents.No matter how the medical certification is de-signed, its source is the existing observationson the decedent, and its statistical function is toserve public health and medical needs.

Cause of death information is now used: (1)to describe the most important current healthproblems; (2) to record frequency of certainrare, fatal diseases; (3) to serve as a startingpoint of epidemiologic studies of specific popu-lations characterized by the disease to which thedeath was assigned; and (4) to assess the fre-quency of conditions associated with death, butwhich are not the direct cause. of death.

Does the underlying cause of death supplydata that are appropriate to these uses? If not,what questions on the medical certification wouldelicit a more valid response for these appli-cations? Are there other uses not nov servedthat could be met with a change in the kind ofinformation requested?

The first use, to describe the most importantcurrent health problems, has changed, at least inthe United States, in the last decade. The NationalHealth Survey can now provide data on the majorillnesses found among the living population.

While it was never sound to use mortality dataas an estimate of morbidity, this was commonlydone in the past. Such a use is no longer defen-sible. The function of the death certificate is stillthat of providing information on those diseasesthat cause death. These data augment those ob-tained on morbidity by supplying data for dis-eases that cause death without previous signs orsymptoms; by evaluating the severity of diseasethrough the fact that it has caused “premature”death; by supplying counts for diseases, that,owing to their rare occurrence, or occurrencein a limited population (say, under 1 month ofage) are not easily reached through surveymethods. In all of these cases, the concept of anunderlying cause of death can provide validinformation, But if disease incidence were viewedas a continuum of information beginning with the~ccurrence of signs and symptoms in the livingpopulation, followed by disabling illness andfinally, death, then the information collected onthe death certificate should be restructured 10parallel the “prevalence” concept used in thecollection of morbidity data. The underlying causeconcept cannot provide prevalence data, or thecounts needed for case fatality data.

The second use, to record the frequency ofrare disepses with high fatality rates is clearlymet by the underlying cause concept. There shouldnot be any difficulty in collecting such informationunder other definitions of the cause of death,

The third use, as a starting point of epi-demiologic studies, is now practically limited tostudies of diseases selected as the underlyingcause of death. Many investigators would pre-

12

fer to follow every occurrence of a disease inthe population of decedents rather than thepopu-lation of persons whose deaths were assigned tothis disease. The larger population can be ap-proached by coding all the diseases reported onthe death certificate. The mention of these dis-eases will still be limited to the physician’s in-terpretation of the response required by thepresent certificate. A thoughtful certifier mayselect only those diseases related to the death,while another physician may list all seriousdiseases present at death. If the epidemiologistwishes to know for how many persons a partic-ular disease contributed to death, it may bepossible to obtain the information from the cur-rent certificate when all conditions reported onthe record are coded. If the epidemiologist needsinformation on how many persons died with a dis-ease, this count cannot be obtained with the pres-ent form of the medical certification.

The fourth use, to assess frequency of con-ditions associated with death but not the directcause of death, has been cited as the chief rea-son for coding all the conditions reported on thedeath certificate, rather than the underlyingcause alone. As pointed out in the previous para-graph, the wording on the present form does notelicit a report of all conditions present at death,not even all serious conditions. Response tospecific queries concerning diseases present atdeath has demonstrated that the entries on thecertificate represent the physician’s judgment orunderstanding of the nature of the report ex-pected from him. The form must be redesignedif conditions present at death are needed.

In summary, the underlying cause conceptcannot generally provide prevalence or incidencedata. It can provide counts for diseases causingdeath, or contributing to the event of death. Wherethere is more than one disease contributing tothe death, the present wording of the certificatedoes not encourage a complete response. Wherethere is a serious disease present that is un-related to the sequence of events resulting indeath, the certificate specifically discouragessuch an entry.

Once a decision is reached on what data areneeded about death for medical and public health

purposes, the requirements must be phrased tofit into the way death certificates are completed,and what is known about decedents. The medicaland social information at hand for a decedentmay vary from that assembled for the person undersystematic lifelong medical care to the one-timeposthumous observation made by the medical ex-aminer of an unidentified person. For the formerindividual there may be a record of his physicalcondition at regular intervals, each illness epi-sode, his last illness, and perhaps an autopsyprotocol. On the basis of this information, whatshould be recorded on the death certificate?How can the questions os instructions in the medi-cal certification be phrased to elicit the dataneeded? Can these questions be so phrased toserve also for the death in w!lich little informationis known?

What approach should be taken to psrmitseparation of data by qualit y—that based on com-plete histories; on attending physician recordsfor a terminal illness only, on autopsy only, etc?Some exploration of quality of diagnostic infor-mation and its effect on medical certification hasbeen reported in special studies, such as one byL M. Moriyama and others. 4 Thus far, there hasnot been any consideration of establishing a rou-tine collection of information on the quality ofmedical certification. Is it possible or desirableto make such measures part of the collectionsystem for m.,rtality statistics?

If it can be decided what data should be col-lected through the medical certifications on deathrecords, it m~.y become easily evident as towhether these data can be obtained through theunderlying cause approach, or through a newconcept. A new concept, and the questions orinstructions needed to produce the desired an-swers would then need to be tested. An ex-periment would need to be devised to learnwhether or not the new form is producing theexpected data.

4Moriyama,L M., Dawber, T. R., and Kannel, W. B.: Eval-

uation of Diagnostic Information Supporting Medical Certifi-

cation of Deaths from Cardiovascular Diseases. National Can-cer fnstitute Monograph No. 19, Jan. 1966. pp. 405-419.

* U. S. GOVERNMENT PRINTUJG OFFICE : 1973 515-214/7013

OUTLINE OF REPORT SERIES FOR VITAL AND HEALTH Statistics

Public Health Service Publication No. 1000

Sei’ies 1.

SeVies 2.

Series 3.

Series 4.

Series 10.

SeYies 11.

Series 12.

SeVies 13.

Series 20.

Sevies 21.

SeTies 22.

l+og~ams and collection procedu~es.— Reports which describe the general programs of the NationalCenter for Health Statistics and its offices and divisions, data collection methods used, definitions,

and other material necessary for understanding the data.

Data evaluation and methods reseavch. —Studies of new statistical methodology including: experi-mental tests of new survey methods, studies of vital statistics collection methods, new analytical

techniques, objective evaluations of reliability of collected data, contributions to ,statistical theory.

Analytical studies. — Reports presenting analytical or interpretive studies based on vital and healthstatistics, carrying the analysis further than the expository types of reports in the other series.

Documents and committee ~epovts. —Final reports of major committees concerned with vital and

health statistics, and documents such as recommended model vital registration laws and revised b~hand death certificates.

Data fvom the Health Intemiew Survey. —Statistics on illness, accidental injuries, disability, use of

hospital, medical, dental, and other services, and other health-related topics, based on data collectedin a continuing national household interview survey.

Data fyom the Health Examination Suvvey. —Data from direct examination, testing, and measure-ment of national samples of the population provide the basis for two types of reports: (1) estimatesof the medically defined prevalence of specific diseases in the United States and the distributions ofthe population with respect to physical, physiological, and psychological characteristics; and (2)analysis of relationships among the various measurements without reference to an explicit finite

universe of persons.

Data fvom the Institutional Population Surveys. —Statistics relating to the health characteristics ofpersons in institutions, and on medical, nursing, and personal care received, based on national

samples of establishments providing these services and samples of the residents or patients.

Data from the Hospital DischaYge .Swvey. —Statistics relating to discharged patients in short-stayhospitals, based on a sample of patient records in a national sample of hospitals.

Data on mortality. —Various statistics on mortality other than as included in annual or monthly

reports— special analyses by cause of death, age, and other demographic variables, also geographic

and time series analyses.

Data on natality, marriage, anddivoYce. -Various statistics on natality, marriage, and divorce otherthan as included in annual or monthly reports—special analyses by demographic variables, alsogeographic and time series analyses, studies of fertility.

Data fyom the National Natality and Mortality surveys. —Statistics on characteristics of births and

deaths not available from the vital records, based on sample surveys stemming from these records,including such topics as mortality by socioeconomic class, medical experience in the last year oflife, characteristics of pregnancy, etc.

For a list of titles of reports published in these series, write to: office of Information

National Center for Health StatisticsU.S. Public Health ServiceWashington, D.C. 20201

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