NATIONAL CENTER 

For HEALTH STATISTICS 

PROPERWOFTHE 

PUBLICATIONSW3/MJC/-/ 

EDITORIAL LIBRARY 

VITAL and HEAL3H STATISTICS 

DATA EVALUATION AND METHODS RESEARCH 

MethodsforMeasuring 

PopulationChange


A SystemsAnalysisSummary 

An introductory study of varying requirements of data for the 

measurement of population change, and of the alternative 

methods which are available to obtain these data, using a 

systems analysis approach. Data requirements are grouped 

into four categories, and seven maior statistical methods are 

explored and rated in terms of their usefulness in furnishing 

each type of data. 

DHEW Publication No. [HSM) 73-1262 

U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE 

Public Health Service 

Health Services and Mentai Health Administration 

Washington, D. C. March 1969 
PubIic Health Service Publication No. 1000-Series 2-No. 32 
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 Development 

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

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

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

EDWARD E. MINTY, Executive O//icer 

MARGERY R. CUNNINGHAM, in./ormation O//icer 

Public Health Service Publication No. 1000-Series 2-No. 32 

Library of Congress Catalog Card Number 71-600267 
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CONTENTS 

1. Introduction


2. The Systems AnalysisApproach


3.	 Matrix of Required Measurement Factors


Data Content Requirements


Population CompositionRequirements


Geographic AreaRequirements


Time Requirements


4.	 The Armamentarium of Statistical Methods


Conventional Population Census


Conventional Vital Registration System


Continuous PopulationRegister


Sample RegistrationSystem


Sample InterviewSurvey


PanelLongitudinal Studies


Demographic Measurement Laboratories


5. Ratings ofMeasurementMethods


References


Appendix. Detailed Notes on Ratings inTableA


Page 

1 

2 

4 

5 

5 

5 

6 

6 

7 

7 

7 

7 

8 

8 

9 

9 

12 

13 
With increasing concern about vapid growth of the population, in this 

country as well as in many less developed countvies, and with the widespread adoption of family planning programs, theve is a growing need 

for methods of measuving population change. Considerable vesources 

have beenand will be expended in the collection of cibta to measwe population change. A systems analysis approach is described which, by exumining difftzrent methods of measurement in relation to the vavying types 

of data required, wowld lay the foundation for decisions on wheve additional theoretical methodological research should be concentrated to 

improve the adequacy and precision of existing methods and to identify 

methodological gups fov which new methods are required. 

The fow broad classes of population data requirements ave summarized 

u?ub four heudings: (1) dab content requirements, (2) population composition Requirements, (3) geographic area veqw”rements, and (4) time 

requirements. 

The ar?namentum”um of statistical methods available to meet these requirements is then explored. The statistical methods are considered 

under seven major headings: (1) the conventional population census, (2) 

the conventional vitul re~”stvation system, (3) continuous population 

ve~”sters, (4) sample rega”stration systems, (5) sample inte-rview surveys, (6) panel lo~”twdinal studies or repetitive cross-section surveys, 

and (7) a combination of methods in “demographic measurement laboratories. ” 

After a brief description of each method, the methods are then examined, 

taking each one separately, as to their suitability with regard to the fow 

gYoups of data requirements. Each method is rated fov each of the data 

requirements ona judgmental scale of strong, medium, and weak. These 

evaluations are summarized in table A (p. 10). 

iv 
METHODS FOR


MEASURING POPULATION CHANGE


A SYSTEMS ANALYSIS SUMMARY 

Forrest E. Linder, Ph. D., Univemity of North Cavolinaa 

1. INTRODUCTION 

The world is now in a period of extremely 

rapid population growth. This is a continuing 

process of growth that started in the far past 

with a slower rate and smaller absolute increments but is now growing at a faster rate with 

rapidly increasing absolute increments. 

Examining official and unofficial estimates 

of past and future world population totals, b 

the following first order differences for successive 50-year intervals can be seen: 

Between 1750-1800, increased 187,000,000 

Between 1800-1850, increased 284,000,000 

Between 1850-1900, increased 388,000,000 

Between 1900-1950, increased 865,000,000 

Between 1950-2000, will increase 3,615,000,000. 

aForrest E. Linder is Professor of Biostatistics at the 

Sahool of Public Health of the University of North Carolina, 

Associate Director of the Carolina Population Center, and 

consultant to the National Center for Health ‘Statistics international statistical program. This study was supported entirely by PHS Research ‘Grant No. HD03441 from tbe National 

Institute of Child Health and Human Development to the University of North Carolina. 

bMany differing population estimates are available, but 

within narrow limits determined by different assumptions and 

methods of calculation, the same broad interpretation emerges. 

The above figures are derived from the U.N. World Population 

Prospects 1 and Durand 2, 

The impact of these rapid increases does not 

fall equally on every country of the world. The 

increases are generally proportionally larger in 

the less developed countries of the world and 

many of these have adopted national policies and 

instituted specific programs designed to slow the 

rate of national population growth. It is estimated -

that more than half the people of the less developed 

nations now live in more than 25 countries 

with policies and programs to reduce birth rates 

by family planning. 3 

The population problem is not limited to 

countries in the early stages of economic development. It is true that for many Americans the 

population question is generally viewed as a world 

problem, and one removed from day-to-day living 

in the United States. But the United States also 

has a domestic population problem although it is 

of a different type than the global problem. 

On a global basis and in the less developed 

countries, there are immediate warnings of extensive starvation with continuing social and 

political unrest. In the United States there is no 

foreseeable danger of wide-spread malnutrition 

due to an overall shortage of food. On a global 

basis there can be valid concern in many areas 

that the population is rapidly approaching a 

magnitude where the land-space is inadequate 

to permit an acceptable mode of life considering 

the probability of slow economic and social 

development. The United States, at least in the 

near future, does not face this desperate space 

problem. 
However, the American people are used to an 

extremely high level of living in terms of open 

space and the domestic population pressure may 

therefore be rapidly approaching unacceptability. 

There is considerable doubt that Americans will 

be willing to gracefully accept drastic changes 

in their accustomed mode of living, and yet 

U.S. population growth is forcing such changes. 

‘These considerations, together with the fact 

that in the United States the deleterious effects 

of population growth are concentrated in the less 

affluent sectors of the population, have led to a 

positive U.S. population policy and programs to 

make family planning information available to 

all who desire it. 4!5 Appropriations specifically 

earmarked for’ population programs by the U.S. 

Congress for research, domestic action programs, and for foreign assistance have rapidly 

increased for the fiscal years 1967, 1968, and 

1969. 

It is easy to recognize that a population 

problem does exist. The crudest type of existing 

statistical data make this evident. But to measure 

more subtle population changes; to evaluate the 

social, economic, and cultural factors that facilitate population change or create barriers to it, 

requires more sophisticated measurement instruments. Programs for the modulation of population growth will be extremely costly, will extend 

over long periods of time, and may produce results that will be obscure in the initial phases. 

Many false starts will be made, many programs 

will fail to penetrate to the population sectors 

most concerned, and some approaches may have 

a negative rather than the expected positive 

effect. 

The timely evaluation of these programs 

will require effective, sensitive, and relatively 

inexpensive measu~ement tools capable not only 

of giving an early indication of changes in vital 

rates but of revealing significant factors related 

to such changes. The statistician concerned with 

such measurement problems has at his dispmal 

a considerable array of measurement methods 

or tools, but each of these methods has certain 

intrinsic limitations as well as varying technical and administrative difficulties or defects. 

A review of these tools, first in relation to 

their suitability to meet the broad needs for 

population change measurement instruments, and 

then, in more depth, with regard to the special 

technical power of each, will be of value in selecting operating methods to be used in the field as 

well as in identifying basic and operations research which may be needed to improve the 

existing methodology. 

2. THE SYSTEMS ANALYSIS 

APPROACHC 

An organized analysis of the attributes of 

statistical methods in relation to the measurement of population change is justified because 

of the extensive resources that are being and 

will continue to be put into data-collection activities. It cannot be assumed that all of these 

methods will be successful and there is substantial evidence, using the criteria of the amount 

of valid data produced on changing vital rates, that 

there is substantial waste effort. The conventional 

census procedure produces no direct data on 

change of vital rates, and the validity of survey 

methods at their present level of technical development has serious defects .d In spite of such 

defects the needs for data are so great that 

survey activity for collecting new data on fertility 

topics will continue to increase. A committee of 

the International Union for the Scientific Study 

of Population has published an extensive list of 

recommended topics for fertility studies. 14 The 

Population Council has published a valuable 

collection of questionnaires on KAP (knowledge, 

attitude, and practice) surveys 15 and is preparing 

a standard operating manual. The U.S. Bureau 

of the Census is recommending to countries 

a comprehensive package of survey proposals 

including suggested methods for measuring vital 

cThe definitions and concept of “systems analysis” differ 

greatly but generally “the systems approach involves identifying a problem, defining the objectives which must be aohieved to solve it, considering alternative methods for meeting 

these objectives, and choo~ing the most attractive alternative 

by rigid cost-effectiveness analy:~~,)y intuition and judgment, or by something in between, 

%om and others have written on nonsampling errors and 

biases in retrospective demographic inquiries. 8“13 The National Center for Health Statistic has published a number of 

studies on survey response error in Vita2 and Health Statiatios, 

Series 2. 
rates. 16 There is a substantial possibility that 

these types of recommendations will encourage 

expanded data-collection activities without a critical appraisal of the validity of the data collected. 

The likelihood of waste effort and invalid results 

are particularly great in reference to ad hoc 

fertility surveys. The conventional census and 

vital statistics systems have deficiencies but at I least these methods have the benefit of over 100 

years of international study and the cooperative 

formulation of recommendations, so that the subject coverage has been reduced to the most 

manageable and important topics and the nature 

of the deficiencies is well known. e Although experience is now being rapidly accumulated, this 

“shakedown” process has barely started for fertility surveys. 

A systems analysis of existing methods in 

relation to present requirements is only an initial 

step in developing a theory of measurement 

of population change. And even a detailed systems 

analysis cannot be definitive since a systems 

analysis is an iterative process leading to different conclusions as requirements and methods 

change and as more precise information on the 

short- comings and strengths of the different 

methods is known. 

The first step in a systems analysis of~pulation change measurement methods would be an 

examination of the broad requirements or uses 

that any system of measurement methods must 

satisfy. These are more complex and interrelated than may seem at first glance and it is 

certain that no one statistical procedure will 

meet all of the requirements. The next step is 

to identify and clearly define the armamentarium 

of statistical tools or methods that can be used 

to deal with the measurement of ~pulation 

change. An examination of the attributes of the 

various methods in relation to the broad requirements would then lay the foundation for decisions on where additional theoretical methodological research should be concentrated to improve 

the adequacy and precision of existing methods 

and to identify methodological gaps for which 

new methods are required. 

eF~rthe la~st formulation of these hterntitiOId rWJmmendationssee UnitedNations Recommendations. 1’7,18 

In examining the extent to which statistical 

methods satisfy the stated requirements it will be 

difficult to separate characteristics of each 

method which are to some degree intrinsic to the 

method from characteristics which are merely 

a consequence of the available resources or 

of good or bad administrative or operational 

practice. 

The different methods do require different 

types of field organization, different types of 

specialized personnel, and different levels of 

financial expenditure. If these factors are substantially changed, then a method as defined 

here becomes almost a different method. It is 

conceivable that almost any deficiency of any 

method could be reduced or eliminated by an 

adequate infusion of operating resources and 

by superior administrative conditions. Inversely, 

of course, even the best technical methods 

can be vitiated by insufficient resources or 

operational incompetence. In spite of this, considering the pattern within which the diffevent 

methods are in fact usually wised, the. methods 

have intrinsic limitations and advantages which 

may be>considered in relation to different measurement requirements. This discussion is concerned primarily with these intrinsic limitations 

and advantages rather than with the characteristics most susceptible to administrative change. 

The broad analysis suggested above should 

then be followed by a detailed study of each 

defined method. These following studies should 

consider each method in detail, carefully identifying the technical character of each method, 

the administrative requirements in terms of 

organization, personnel and budget, synthesizing 

practical experience that has. accumulated, and 

revealing important technical problems which 

require new basic or operational research. 

It is the purpose of this paper to attempt 

only the initial broad analysis of requirements 

and methods. A detailed examination of the 

attributes of each statistical tool can then follow 

with the benefit of some overall reference framework within which each method can be oriented. 

For either the broad analysis or the detailed 

examination of an individual method it is important to have a practical judgment of how much 

precision is really required to serve the pur-
poses for which the data are collected. Perfect data are seldom if ever necessary. Even 

approximate data may be sufficient to indicate 

a general course of action and rough data may be 

sufficient to permit an administrative judgment 

as to whether that course of action needs to 

be changed. With regard to the soundness of their 

statistical bases, many public health programs 

have proceeded on a philosophy of “as if” and 

with regard to population action programs many 

different types of considerations other than those 

based on statistical fact may determine their 

direction, thrust, and velocity. Nevertheless, it 

can scarcely be denied that accurate data can 

be used to avoid tremendous waste in planning 

and evaluating administrative operations and in 

general, more precision makes possible more 

rational program administration. 

It is also necessary to define the Ixmndaries 

within which the systems analysis is to be undertaken. The concept of a systems analysis is 

broad in scope and, without definite boundaries, 

the analysis could tend to range in a too amorphous manner over the entire field of statistical 

method. There are numerous requirements and 

subrequirements for data and numerous minute 

features of the different methods. These are 

interrelated to form a complex too broad for a 

single treatment. There is, of course, a vast 

literature dealing with the mathematical or 

analytical adjustment, graduation, subtabulation 

and computational treatment of defective data, 

and with extracting estimates of vital rates from 

partial information. Some of these methods and 

new techniques are summarized in various sessions of professional conferences. 19 The United 

Nations has also published a detailed manual on 

these methods. 20 This article is not intended to 

deal with this class of method but rather to be 

directed to the problems of obtaining more adequate data in the first place. 

Even in the area of original data collection 

there are certain types of problems which will 

not be considered. In general, consideration will 

be limited to those methods most directly applicable to the measurement of the net effects of 

programs intended to achieve some reduction in 

the rate of population growth. Within these terms 

of reference there are some statistical problems 

and methods which are not studied. Some of these 

are methods relating to administrative evaluation 

of operating programs, the collection of service 

statistics, 21 and the use of microsimulation 

schemes to estimate vital rate changes .22 

3. MATRIX OF REQUIRED 

MEASUREMENT FACTORS 

The required factors or attributes that any 

measurement system should have depends upon 

the broad purpose that the system is designed 

to serve. 28 Some statistical systems are designed to serve a number of different purposes, 

and the methods used evolve into a compromise 

procedure which is thought appropriate to balance 

its suitability to these various purposes. The 

intent here, however, is not to examine the major 

statistical data-collection methods from the point 

of view of their adequacy in meeting several 

general needs, but to examine in a more limited 

way their adequacy in meeting the specialized 

purposes as measuring tools to detect the end 

results of programs directed at the reduction 

of the rate of population growth-that is, the 

measurement of changes in vital rates (birth 

and death rates) or the measurement of the net 

results of such changes. 

The variety and pioneering character of the 

population modulation programs that are being 

initiated in various countries of the world is 

evidence that even within the limits of the purpose stated above, measurement methods must 

be designed that will satisfy a number of distinct 

requirements. It is obvious that one single method 

or procedure will not suffice. In brief, the requirements that must be met can be grouped into 

four broad classes: (1) data content / requirements, (2) population composition requirements, 

(3) geographic area requirements, and (4) time 

requirements. The optimum satisfaction of only 

one of each of these requirements might result 

in the selection of a statistical method that 

would be entirely inadequate in relation to the 

other groups of requirements, But since these 

groups of needs are all interrelated and must all 

be satisfied to some extent, they constitute a 

matrix of requirements. In effect this matrix 

becomes a multidimensional mold which partially defines the desired measurement tools. 

It is clear that the matrix described for dis -

4 
I 

I 

I 

i 

( 

I 

! 

, 

cussion is not a complete matrix for evaluation 

purposes, since the choice of a measurement 

method to be used may depend upon factors not 

considered in detail here such as cost requirements, needs for specialized personnel, specifications for minimum sampling errors, and so 

forth. It is hoped that factors such as these will 

be considered in more detail in subsequent analysis of the methods. 

Data Content Requirements 

If the primary purpose under consideration 

here is the measurement of changes in vital 

rates, the main requirement with regard to data 

content is that the method include information 

on the number of births and deaths together with 

any additional information which is necessary to 

convert such gross numbers to rates. While this 

is the obvious major requirement, it is by no 

means sufficient, since the appraisal of the 

effects and causes of population control programs 

requires knowledge of many factors related to 

the manner and rapidity of population change as 

well as the range of variables which may affect, 

in a positive or negative way, the design and 

operation of the population programs themselves. 

The International Union for the Scientific Study 

of Population 14 as well as other agencies has 

made recommendations for items for such related variables. 

No doubt some of the many items suggested 

have little or marginal value and in time a more 

concise list of essential and tested items will 

emerge. However, there is no doubt that any completely satisfactory statistical procedure must be 

capable of coping with the collection, processing, 

and analysis of a wide variety of substantive 

items. It does not follow, of course, that any 

single statistical tool must encompass the whole 

range of substantive topics, but the available 

armamentarium of tools must meet the needs 

for many different types of data. 

Population Composition Requirements 

The substantive items referred to above are 

in many cases of little value unless they can be expressed as rates by reference to an appropriate 

population base. This obviously requires that the 

total population serve as a base but it is also es. 

sential that the various strata or elements that 

makeup the composition of the total population 

serve as bases. The population of any nation is not 

usually spread evenly over all population composition elements and population action programs must 

be designed to differentially relate to these 

elements. For example, in some countries the 

population problem may be more or less acute 

among the different economic classes. In some 

instances, the more affluent economic classes 

may already have easy access to family planning 

information with the resultant birth rates reflecting their desired family-size norms. In the 

United States this is the case and accordingly 

the thrust of the official programs is to bring 

this same knowledge to the less affluent sectors 

of the population. In other countries the population 

problem may be primarily the problem of the 

predominantly rural areas. 

For such reasons, the whole necessary analysis of the changes of population may depend upon 

a differential study of numerous sectors of the 

population—by social and economic variables, by 

education, by demographic ‘variables such as age, 

by urban-rural sectors of the populations, and by 

various religious, ethnic, and nationality groups. 

The point is not only whether these data can be 

collected in relation to the data-content items 

discussed above but whether a population base 

for rate computation can be also compiled and 

classified according to these variables. Some survey designs and other data-collection systems 

may produce the numerator information for rate 

calculation but fail to produce the denominator 

population base classified by the required categories. 

Geographic Area Requirements 

The geographic area requirements for adequate measurement of population change are perhaps the most difficult to meet. For certain 

important purposes, such as national economic 

planning, a nationwide measure of change in 

vital rates is most essential, since these rates 

determine the gross rate of population growth 

and this in turn defines an important aspect of 

a national plan for economic and social progress. 

However, action population programs are not 

5 
necessarily administered in a uniform way from 

a national center and, even if they were, the 

problems and results vary by geographic areas 

as well as by population composition factors. 

In large federated countries, program administration may be a responsibility of state or 

provincial administrations with great variation 

in the program design, available resources, 

and efficiency of administration. This creates 

a demand for population growth data not only for 

the national totals, but for subnational geographic 

or political divisions such as ‘states, cities, and 

minor civil divisions. Since family plaming programs are still in an experimental stage of 

development there may also be a need for precise 

data for large program developmental regions 

or areas and even for small experimental units 

established to evaluate different program designs. 

From a theoretical point of view it is conceivable that an ideal statistical method could 

be designed and successfully applied to the 

smallest geographic area required and that this 

method could then be expanded to larger and 

larger geographic units until the total national 

area was covered. However the resource and 

logistic demands of this approach for most if not 

all of the methods considered here would seem 

to rule it out as a practical approach for the near 

future. 

Time Requirements 

Familv planning programs are difficult to 

organize and are extremely expensive in terms of 

budget and manpower. Such programs are designed 

in various ways based on differing premises and 

differing strategies of program operation. To 

prevent enormous waste effort it is essential 

that some method of appraising the effective results of such programs be used which can detect 

changes in population growth rates over relatively short time periods. For more classical 

types of demographic analysis or for historical 

demography such long-interval statistical procedures such as the traditional census may be 

adequate. It was from the analysis of decennial 

census data that the world has been brought to 

an appreciation of the urgency and magnitude of 

the world population problem. However, for program evaluation a decade-interval is much too 

long as a statistical measure of population change. 

In addition to the needs for evaluation of population action programs, the study of short-term 

changes in vital rates, such as those related to 

economic fluctuations, war activities, and poor 

agricultural seasons, require at least a year-toyear measure of changes in vital rates, and for 

some purposes an even more current index. 

4. THE ARMAMENTARIUM OF 

STATISTICAL METHODS 

It will be clear that to meet the specifications 

of the’ matrix of required measurement factors 

a variety of statistical methods may have to be 

employed. Broadly speaking the statistical methods which are available as data-collection procedures may be considered under seven major 

headings: (1) the conventional population census, 

(2) the conventional vital registration system, 

(3) continuous population registers, (4) sample 

registration system, (5) sample interview surveys, (6) panel longitudinal studies or repetitive 

cross-section surveys, and (7) a combination of 

methods which might be called “demographic 

measurement laboratories. ” The total statistical program in any country directed at measuring 

population changes and carried on by official 

and unofficial data-collecting and research agencies will probably comprise some combination of 

all of tiese methods. Yet, a careful examination 

of each major method in relation to the matrix 

of requirements will permit the development of 

an eclectic compilation and research program of 

maximum utility. 

Among the seven major groups of statistical methods listed, the conventional population 

census and the conventional vital registration 

system have rather clear internationally accepted 

definitions. 17,18,2425 The othermethods require 

some additional degree of definition and description before they can be evaluated in terms of the 

general requirements that have been set up. Even 

for the census and the vital registration system 

it may be worthwhile to reemphasize some of 

their essential attributes in the same manner as 

for the other methods, so that the different 

methods as defined and discussed in this article 

are clearly ‘differentiated. 

6 
Conventional Population Census 

The concept of the conventional population 

census is generally well understood, but the term 

is sometimes used also to refer to a variety of 

data collection procedures which are not’ ‘population censuses” in the more precise meaning of 

the term. The examination of the census in 

this paper refers to the method defined by the 

United Nations 25”in these terms: “A census of 

population may be defined as the total process 

of collecting, compiling and publishing demographic,economic and social data pertaining at 

a specified time or times, to all persons in a 

country or delimited area. ” The United Nations 

source lists some of the essential features of 

a national census as: (1) must be officially 

sponsored or carried out by a national government, (2) must relate to a precisely defined area, 

(3) must be universal in the sense of covering all 

persons within the defined scope of the census, 

(4) must be a total enumeration referring to a 

well-defined point in time, (5) must be a collection 

of separate data for each individual and not 

merely some process of aggregating group totals, 

and (6) must be carried through to the compilation 

and publication of data by geographic areas and 

by basic demographic variables. 

Conventional Vital Registration System 

Some form of legal provision and permanent 

organization for the continuous registration of 

vital events exists in practically every nation 

of the world. The United Nations Handbook of 

VW Statistics Methods’4 defines this process 

as follows: “. . . a vital statistics system can 

be defined as including the legal registration, 

statistical recording and reporting of the occurrence of, and the collection, compilation, analysis, presentation, and distribution of statistics 

pertaining to ‘vital events’, which in turn include 

live births, deaths, fetal deaths, marriages, divorces, adoptions, legitimations, recognitions, 

annulments, and legal separations .” The registration method is defined as “. . . the continuous 

and permanent, compulsory recording of the 

occurrence and the characteristics of vital events 

primarily for their value as legal documents as 

provided by law and secondarily for their usefulness as a source of statistics . ...” 

Obviously the vital statistics systems of 

most countries fall short of this comprehensive 

definition in one way or another, either by not 

covering all of the different vital events specified 

or by operational deficiencies in covering completely the types of events specified by the 

national legal basis of the system. In this paper 

the primary concern is with the system as the 

source of statistics on births and deaths although 

the other vital events are also of interest as 

factors indirectly related to population growth. 

Continuous Population Register 

The continuous population register starts with 

a base of census-type information to which continuous corrections and additions are made with 

an input of data derived from a vital registration 

system and other administrative reports. Because 

of the necessity to make change-of-residence 

corrections the record systems are typically 

maintained at a local level. The method of extracting statistical information from a large 

number of local registers and consolidating it 

for national totals varies from system tos ystem. 

Population register systems are theoretically 

attractive because the same system produces data 

on the number of births and deaths as well as the 

corresponding population base. However, the systems are highly sophisticated in that they require 

very precise input data, a disciplined and literate 

population to report regularly changes in demographic status, and accurate procedures for 

matching records and compiling data from them. 

The concept of a continuous population register is not uniquely defined. Many variations in 

the design and the purposes of thes ystems exist. 26 

The best known systems are those in several north 

European countries and the Japanese Koseki system, In most instances the systems have not been 

established for the purpose of creating statistics 

but for other administrative objectives and in 

general the statistical output from the systems 

has been disappointing, although increasing attention has been given to this statistical byproduct 

of the systems .27 

Sample Registration System 

The conventional registration system fails 

to serve its purposes in many situations because 

7 
I


the technical manpower and financial resources 

are inadequate to produce vital statistics at a 

useful level of quality. The concept of a sample 

vital statistics system is that available resources 

could be concentrated on the administration of 

vital registration in a limited group of geographic 

areas selected as an adequate sample of the whole 

country or some subnational major civil division 

and in this way produce an acceptably accurate 

estimate of birth and death rates for that political geographic unit. Earlier descriptions of 

the sample registration concept 28visualized the 

sample registration units as reinforced units 

of the already existing national registration system so that the number of sample units could 

be gradually increased resulting ultimately in an 

improved nationwide conventional vital registration system. Since a vital registration system 

does not in itself produce the population base 

figures necessary for the computation of vital 

rates, most experimental efforts to establish a 

sample vital registration system have included an 

overlay of sample interview surveys partly to 

estimate the population of the sample area and 

partly to yield an independent report of births 

and deaths based on retrospective responses of 

the interviewees. A rather wide variety of designs 

have been tried, some in which the registration 

element of the system is quite independent of the 

official registration organization, some in which 

elaborate matching between the individual records 

of the registration and surve~ is attempted, and 

some in which the method is essentially a sequence 

of surveys with less emphasis on the continuous 

registration process. Some of these variations in 

method are described in a number of papers .29-34 

Sample Interview Survey 

In some respects the sample interview survey 

method resembles the census technique except 

that with the advance in the theory and practice 

of population sampling these surveys can be conducted on a smaller number of respondents—a fact 

which permits many changes in data collecting 

techniques. Sample surveys for demographic purposes may be conducted with sample units consisting of individuals, households, or defined 

geographic areas. The items of data collected 

may be items of current fact (e.g., present 

marital status) or retrospective items (e.g., 

total number of children ever born). Surveys can 

be designed to produce estimates of a wide variety 

of items and at the same time population estimates in the required detail to convert the gross 

estimates of the variables to demographic ratios 

or rates. Sample surveys have almost unlimited 

flexibility as to the scope of their subject matter 

and geographic coverage, but their wide potential 

and relative economy tends to encourage their use 

without due attention to the many technical problems of survey design and administration and 

without a critical evaluation of the validity of 

the data collected for newer and untested topics. 

Nevertheless the power and the adaptability of 

the sample interview survey assure it a role of 

increasing prominence as a method of collecting 

data on factors related to population change. 

Panel Longitudinal Studies 

The concept of the panel longitudinal followup 

method of studying population change is simply 

that of selecting an initial panel of persons, 

according to criteria determined by the purposes 

of the Istudy, and making periodic observations on 

this group by repeated interview surveys and the 

collection of other records so as to create a 

complete history of the changing facts which are 

pertinent to the study for each person in the panel. 

Unfortunately the needs and requirements for this 

method of study have not been clearly analyzed 

and they are generally difficult from an administrative as well as an analytical point of view.’6 

The term “longitudinal” study is applied to a 

number of quite different study designs, and for 

some of these designs, even if data are collected 

longitudinally, the analysis is basically little more 

than a series of cross-section studies. Longitudinal studies are essential where a variable must 

in some sense be integrated over a time period 

for each individual or where the outcome of a 

particular act is being studied. While important 

for medical studies, longitudinal types of investigation would seem to have fewer advantages for 

general studies of population change. Studies of 

this type require perhaps more sophistication and 

data collecting precision than population register 

systems, but are more feasible because the number of persons in a panel is usually quite small. 

8 
Demographic Measurement Laboratories 

The concept of a demographic measurement 

laboratory is a relatively new concept for demographic studies, but is a long established method 

for the study of health conditions of a population 

and for developing improved methods for measuring such attributes. The Eastern Health District 

of Baltimore established in the 1930’s by Johns 

Hopkins School of Hygiene, the Hagerstown area 

administered by the U.S. Public Health Service, 

the Tecumseh area in Michigan designed by the 

Michigan School of Public Health, the Arsenal 

Health district in Pennsylvania established by the 

Pittsburgh School of Public Health, and the California Population Laboratory under the direction 

of the California State Health Department are 

varying examples of this general concept as 

applied to problems of population health and medical care. These different study areas have produced a great wealth of published data on health 

and health measurement methodology, but unfortunately there seems to be no general review 

article which examines the general concept as a 

statistical method. 

The concept as applied to population is 

simply that of defining a fixed geographic area 

and using all available continuous and ad hoc 

.etatistical procedures for collecting the maximum amount of information for that area that 

pertains to the topics under study. Since many 

different types of. data can be collected and all 

available methods can @ used, the total pool 

of data which becomes available has much greater 

analytical potential than if the same data collection 

efforts were dispersed over different population 

areas. Further, since a great deal becomes known 

about the population of the area, it forms an 

ideal situation in which to test the validity of new 

measurement methods. 

The demographic measurement laboratory 

concept permits a variable design, but ideally 

the laboratory should include a specific geo­

‘As stated above, the laboratory concept has not yet been 

developed in detail for the study of population or population 

measurement methods. However, tbe studies carried on in the 

Gandigram area of Madras ‘State, India and intensive area 

Studies such as those of “Singur, West Bengal, India are examples of early applications of thie approach. 

graphic area, for which maps and a ‘house 

numbering system are maintained, a periodic 

population census taken, an upgraded sample or 

complete vital registration system established, 

and a permanent central office where data from 

these continuing processes as well as from ad hoc 

surveys and studies can be collated, linked, and 

analyzed. The data obtained from a limited geographic area of this type may have validity for 

that area, but the extent to which they can be 

given a broader generality depends upon the extent 

to which the laboratory population can be considered to represent a broader group. 

5. RATINGS OF MEASUREMENT 

METHODS 

Table A gives the results of an examination 

of each method defined above in terms of the 

degree to which the method seems to satisfy the 

broad measurement requirements with which this 

particular analysis is concerned. The ratings or 

evaluations are on a rough judgmental scale of 

stiong, medium, and weak. It is recognized that 

these summary ratings are judgmental in character but they do depend on an examination of 

essential attributes of the method itself modified 

by knowledge of the experience with these methods 

as they have been actually applied and administered in various countries throughout the world. 

Because of the qualitative nature of the evaluations 

or ratings, it is expected that other investigators might give somewhat differing weights to 

various attributes of each method and would have 

differing appraisals of the accumulated experience 

on their use. The ratings assjgned by the author 

are supported to some extent by the detailed notes 

given in the appendix. For convenience in reference the paragraph numbers in the notes correspond to the numbers of the entries in table A 

so that ready reference can be made from the 

table to the corresponding comment. ‘The comments or notes given in the appendix for each 

rating in table A, by no means, constitute a complete justification or detense of the ratings, but 

they do in@cate some of the factors and the line 

of thought that lead to the evaluation. It would 

be differences of opinion in the selection and 

evaluation of these factors that would result in 

different ratings. 

I 9 
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Table A. VARIOUS METHODS OF MEASURING CHANGE RATED ACCORDING TO THE DEGREE TO 

WHICH THEY SATISFY BROAD MEASUREMENT REQUIREMENTS 

[The numbers in each cell of the table correspond to paragraph numbers in the appendix,


which is a justification of the ratings givenl


REQUIRED MEASUREMENT FACTORS


STATISTICAL METHODS FOR


MEASURING POPULATION CHANGE


Subject Geographic Population


Time


Centent Area Composition


Conventional population census 1. weak 2. strong 3. strong 4. weak 

Conventional vital registration system- 5. weak 6. strong 7. weak 8. medium 

Continuous population register 9. medium 10. strong 11. weak 12. strong 

Sample registration system 13. medium 14. medium 15. weak 16. strong 

Sample interview system 17. strong 18. medium 19. strong 20. strong 

Panel longitudinal follow-up 21. medium 22. weak 23. weak 24. medium 

Demographic laboratory 25. strong 26. weak 27. strong 28. strong 
Such differences in ratings would not, however, destroy the value of table A since even 

allowing for variation some observations can 

emerge and these will be a useful guide to the 

selection of methods that have the greatest potential of satisfying the general requirements for 

measuring current population change. It is immediately obvious fi’om table A that no one 

method alone will meet all of the basic needs 

of a country for essential population data and 

the ratings in table A can serve as a guide in 

designing the overall measurement system, with 

each method playing a proportionate part so that 

the total effective result is maximized. 

This summary systems analysis of the broad 

characteristics of population measurement methods is also intended to focus attention on the 

soft or weak features of each to assist in the 

focusing of future methodological research. For 

example, the conventional population census is the 

most fundamental and universally used method of 

collecting data on population and related characteristics, Yet the procedure is weak as regards 

the “time” requirement. mere is typically along 

delay between the population enumeration and the 

date when the tabulated results become available, and there is generally a 10-year interval 

between censuses. Yet it may be possible to improve on both of these features. Continued research on character-reading methods of data 

processing, computer tabulation, and the introduction of sampling methods at various stages of 

census processing may appreciably improve ~he 

rapidity with which census results are obtained. 

The increasing practice of taking quinquennial 

censuses will cut the intercensal interval in half. 

On the other hand, the weakness of the census 

method with regard to subject content pertinent 

to measuring population change is likely to be 

more intractable. As a major national statistical 

collection method the general census must serve 

many purposes and the cost of a total census 

is so large that there must necessarily be a 

tight restriction on the number of items included. 

It is hardly conceivable that a population census 

could ever give the subject coverage required for 

KAP studies or could cover any large number of 

the items recommended for fertility surveys 

by the International Union for the Scientific 

Study of Population. 

Each method can be examined carefully not 

only to determine its defects as the method is 

now usually used but to probe for features that 

can most feasibly be improved. A concentration 

of theoretical and applied research on such features may more rapidly develop the method so 

that it is more efficient in meeting the types 

of requirements described in this paper. 

However, the summary analysis presented 

here cannot serve fully as a basis for either 

designing the overall national measurement system or identifying completely the areas of 

needed methodological research. These objectives require a more detailed and comprehensive 

systems analysis of each method for which this 

summary analysis can serve as a framework 

or background. Such a more detailed analysis 

for each method should go beyond consideration 

of the broad measurement factors considered 

here, and examine the available evidence as to 

the technical validity of the method as well 

as to survey more completely the administrative 

experience that has been obtained for each 

method. Such studies would then identify in detail 

the needed theoretical and operations research 

which could lead to the design of more adequate methods to meet the urgent needs outlined 

in the first part of this paper. 

11 
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2Durand, J. D.: The modern expansion of the world’s population. Proceedings of the American Philosophical Society 

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3Notestein, F. W.: The population crisis, reasons for hope. 

Foreign Affairs Oct. 1967. p. 171. 

4Corsa, L.: United States, Public policy and programs in 

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5Cohen, W. J.: Freedom of choice. Studies in Family PZanning No. %. Population Council, Oct. 1967. pp. 2-5. 

6Systems analysis, no panacea for nations domestic problems. Science 158:102811029, Nov. 24, 1967. 

7Systems Analysis and Policy Planning, editsd by E. ‘S. 

Quade and W. I. Boucher. New York. American Elsevier Publishing Company, Inc., 1968. 

8Som, R. K.: On recall lapse in demographic etudies. international Population Conference. Vienna, 1959. pp. 50-61. 

‘“flom, R. K., and others: Preliminary estimates of birth 

and death rates and of the rate of growth of population, 14th 

round, July 1958-July 1959. National Sample Survey Draft No. 

36.	 Indian ‘Statistical Institute, 1958-60. 

10%m, R. K.: Response bias in demographic enquiries. 

Proceedings of the world Population Conference In: 179-182, 

1965. 

1 lUnited Nations Economic Commission for Africa: Technical paper on non-sampling errors and biases in retrospective 

demographic enquiries, E/CN14/ CKS.*flS/3. 

12Sabagh, G., and Scott, C.: An evaluation of the use of 

retrospective questionnaires for obtaining vital data, the experience of the, Moroccan multi-purpose sample survey of 

1961-1963. Proceeding of the World Population Conference 

111:203,1965. 

13Horvitz, D. G.: Problems in designing interview surveys 

to measure population growth. Prooeedinge of the SociaZ Statistics Section, American Statistical Association. 1966. PP. 

245-249. 

141ntsrnational Union for Scientific Study of Population: 

Variable8 for Comparative Fertility Studies. June 1967. 

15The Population Council: Selected @e8tionnaires on 

Knowledge, Attitudes, and Practice of Family Planning. 2 

VOIS. Aug. 1967. 

16U.S. Bureau of the Census: Atlantida, a case study in 

household sample surveys, unit 11, content and design of 

household surveys. Series ISPO-1. Washington, D. C., 1965. 

17Uni@d Nations: Principles and recommendations for the 

1970 population censuses. Statistical Papere, Series M, No. 

44. United Nations, New York. 11967. 

18United Nations: Recommendations for the improvement 

and standardization of vital statistics. E/CN. 3/388/Add. 1, 

Jan. 1968. 

lgKeyfitz, N.: New developments in measurement and analysis of factors of population growth and structure. Proceedings of the World Population Conference 1:65-69, 1965. 

12 

20United Nations: Methode of estimating basic demographic measures from incomplete data. Manual IV. Manuals 

on Methods of Estimating Population, ST/SOA/Series A/42, 

‘Sales No. 67.XIIL 2, 1967. 

21 The Population Council: A Handbook forservice Statistics in Family Planning Programs. New York. The Population 

Council, 1968. 

2%orvitz, D. G.; Giesbrcht, F.: and Lachenbruch, P. A.: 

Micro-simulation of vital events in a large population. Paper 

preeented at ,meeting of Biometrics Society, Atlanta, 1967. 

Research Triangle Institute and University of North Carolina. 

23 Linder, F. E., and “Simmons, W. R.: Objectives and requirements for measurement of vital rates.1 Proceeding of the 

Social Statistics Section, American Statistical Association, 

1966. pp. 240-244. 

2*United’Nations: Studies in methods. Handbook of Vital 

Statistics Methode, Series F, No. 7, 1955. 

25United Nations: ‘Studies in methods. Handbook of Population Ceneue Methods, Vol. 1, Series F, No. 5, Rev. 1, 1958. 

26United Nations: Methodology and evaluation of continuous population [registers. U.N. Statistical Commission, 12th 

Session, Dec E/CN.3/293, 1962. p. 41. 

27Hofs@n, E. v.; population registers and COmpUterS, new 

possibilities for the production of demographic data. Review 

of the International Statistical Institute 34(2):186-194, 1966. 

28Hauser, p. M.: The use of sampling for vital records and 

vital statistics. Bulletin of the World Health Organization 

11(1-2):5-24, 1954. 

29 Cavanaugh, J. A.: ‘Sample vital registration experiment. 

Proceedings of the International Population Conference 2:363-

371. New York, 1961. 

30Lauriat, P.: Field experience in estimating population 

growth. Demography 4(1):228-243, 1967. 

31Ahmed, No, and ffrot~,, K. J.: Simultaneous estimations 

of population growth-the Pakistan experiment. Quarterly Journal of the Institute of Development Economics IH(1):37-65. 

Karachi, Pakistan. Spring, 1963. 

32Unitecf Nations: Gwanabara Demographic Pilot SurveY, a 

Joint Project of the United Natione and the Government of 

BraziZ. United Nations, New York. (Undated) 

33Manceau, Jo N.s Sample survey of the registration areas 

of deaths and fetal deaths in the Brazilian Northeast Region. 

Review of the Intemutional Statistical Institute 36(1):43-67, 

1968. 

34Wells, H. B., and Agrawal, B. L.: Sample registration in 

India. Demography 4(1):347-387, 1967. 

35Kodlin, D., and Thompson, D. J.: An appraisal of the 

longitudinal approach to studies in growth and development. 

Monographs of the Society for Research h Child Development, 

Vol. XXIII, Serial 67, No. 1, 1958. 

36United Nations: Report of the I%h Seesion of the Statistical Commission. Dec. E/CN.3/304, May 1962. 

371ndian Statistical Institute: The use of the National 

‘Sample “Survey in the estimation of current birth and death 

rates in India. Proceedings of the International Population 

Conference. 2:395-402. New York, 1961. 
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APPENDIX 

DETAILED NOTES ON RATINGS IN TABLE A 

Table A. Various methods of measuring population change rated according to the degree to which 

they satisfy broad measurement requirements 

[The numbers in ench cell of the table correspond@ p-mgmpb numbers in this appendix, which is a justification of tbe ratings given] 

$ 

Statistical methods for Required measurement factors 

measuring population change 

Population Subject content Geographic area Composition Time

Conventional population census 1. weak I 2. strong I 3. strong I 4. weak 

Conventional vital registration 

system 5. weak 6. strong 7. weak 8. medium 

Continuous population register medium 10. strong weak 12. strong 

Sample registration system 1?: medium 14. medium :;: weak 16. strong 

Sample interview system 17, strong 18. medium 19. strong 20. strong 

Panel longitudinal follow-up 21. medium 22. weak 23. weak 24. medium 

Demographic laboratory 25. strong 26. weak 27. strong 28. strong 

1. Census - content (weak): The subject-matter 

content of the traditional population census is limited 

by the large cost of collecting data on many variables 

for a total population. The fact that most censuses are 

taken as official governmental projects under penalties 

for nonresponse, tends also to restrict the census content to those few items which the govemmentis willing 

to consider so important asto justifya mandatory reaponse. The census,asUnitedNationsrecommendations 

for the 1970 World Census17 show, is typically designed 

as a multipurpose statistical instrument, providing 

most essential national data on a variety of subject 

topics. The content coverage in terms of the number of 

items included for any one topic (e.g., fertility) is 

therefore quite restricted. The newer census practices 

of covering the total population with only a few basic 

items and expanding the subject coverage, utilizing 

subsamples of the population, greatlyincreasethe scope 

of the census. Censuses of this design mightbe consideredas “medium” with regard to coverage. 

2. Census -avea (strong): The area coverageof 

the census is its strongest characteristic. Bydefinition 

the term “census” connotes a national census and this 

is universally true except insofar as a few censuses 

in special cases may omit by design some relatively 

minor sector of the national territory because of reasons such as inaccessibility. Since by definition a“cenSUS” covers 100 percent ofthepopulationg the volume 

of data is adequate to permit tabulation and detailed 

cross-tabulation of items for major and minor civil 

divisions. Census data is almost universally tabulated 

in some detail for states or provinces, subnational 

regions, individual large cities, counties, and sometimes even for smaller geographicunits, suchascensus 

tracts. If the subject-matter scope of a census is 

increased through the use ofpopulation subsamples,the 

validity oftabulating theseitemsfor smallergeographic 

areas is weakened. 

3. Census - composition (strong): Since one of 

the primary purposes of the censusis to determine the 

composition of the population thisis one ofthe census’ 

strong ‘attributes. Many of the census items relate to 

the economic, social, and educational status of the population. To the extent that the census also includes 

items of more formal demographic interest (age structure, marital history, and fertility history) the census 

provides an extremely rich source of data for demographic analysis. Again, as in the case of tabulation 

gBaSerlcmtbe IJ.N. definition of a census, tbe term “sample census” is really a contradiction of terms. 

13

by areas, the large volume of census data permits 

tabulation and cross-tabulation of demographic variables in great detail according to the population composition groups, 

4. Census - time (weak): As a statistical tool 

for measuring population change the census is weak in 

two ways regarding the time factor. As a major and 

expensive nationwide statistical effort the usual practice 

is to take a census at 10-year intervals. While a 

sequence of decennial censuses provides an excellent 

base for long-range studies of historical demography 

and perhaps the most complete base for analyzing 

changes over the past decades, the long interval between censuses does not provide a sensitive method of 

measuring current population change which is required 

to evaluate population action programs. The decennial 

census interval is also too long for the effective use of 

census data for other national purposes and consequently 

more and more countries are establishing a tradition 

of quinquennial censuses. However, for measurement of 

current population change a 5-year interval is also too 

long. The second time defect of the nationwide census 

arises from the bulk of data processing required with 

the result that in ordinary circumstances census tabulations, except for a few total figures, are typically not 

available for 2 to 3 years after the date of the enumeration. In many cases the pttblication of the certsus results 

extends over a longer time span. This means that the 

most recent available decennial census data are usually 

3 to 13 years old. With an increasing pattern of quinquennial censuses and the use of electronic computers, 

the conventional national census procedure is being 

greatly improved, but even so, the census is not an 

adequate statistical method from the standpoint’ of the 

time variable for measuring current ~o@a:ion change. 

5. Vifal reg”stvation - content (weak):’- ?he vital 

registration system exists originally and primarily as 

an official method of establishing the legal fact of birth 

and death. The statistical uses of the system are secondary byproducts. Accordingly many items on the 

registration document are for the purpose of establishing identity and family relationship and other legal 

characteristics of the vital event and have little or no 

value as analytical variables in studying population 

change. This priority of items, in combination with the 

necessity for administrative reasons to keep the total 

number of items limited, results in a registration 

document with a paucity of information relating to 

factors affecting population change. Those demographic 

items which are included are usually highly relevant to 

the analysis of population change and, - of course, the 

fakt of birth or death established by a registration 

system is the datum of greatest importance to this 

question. Nevertheless, the statistical content of the 

vital registration system is one of its weak aspects. 

6. Vital re~”stratwn - area (strong): As with the 

census, the area factor of the registration system is a 

strong point. A registration system, presumably covering all of the population of a nation, can be the source of 

birth and death information for every civil subdivision 

even to the smallest village. This strong feature of the 

registration system—the ability to provide data on 

vital events for subnational geographic areas—is somewhat dampened &cause the gross number of births and 

deaths for an area has little meaning unless it can be 

related in the form of rates to the populations from 

which the births and deaths arise (the population exposed to risk). Because many births or deaths occur in 

areas other than those in which the principals concerned usually reside, it is difficult in many cases to 

tabulate the data so that there is a correct relationship 

between the population exposed to risk and the vital 

events. This factor is negligible for data tabulated for 

national totals but becomes more and more serious 

as the geographic tabulation unit becomes smaller and 

smaller. It is, of course, particularly serious in the 

case of small geographic units containing medical 

facilities that attract births and deaths across boundary 

lines from adjacent geographic units. Most modern 

vital statistics systems attempt to correct this defect 

by a reallocation of nonresidents. 

7. Vital veg%”stvation- composition (weuk): National vital registration systems are usually weak insofar as information on the registration record which 

would permit compilation of the data according to the 

economic, social, and demographic composition of the 

population. The latest draft of United Nations recommendations18 for the contents of the birth record include only a few priority factors of this kind. Typically 

vital statistics are not available by income, occupation, 

education, literacy, and other important variables 

corresponding to population composition groups. 

8. Vital vegz”stration - time (medium): Since the 

registration system operates continuously it does not 

suffer from the same time deficiencies as the periodic 

census. Also since the total volume of individual records 

for births and deaths to be processed in any 1 year 

would be only about 2.5 percent to 7.0 percent of the 

volume of census records the system potentially could 

produce annual reports on the number of vital events 

with an acceptable timelag” in tabulation and publication. 

Provisional totals are sometimes available on a monthly 

or quarterly basis with a timelag of only 3 to 4 months. 

W@h a periodic census as a base, current birth and 

death data permit the continuous calculation of a national 

population total, assuming international migration is 

negligible or, as is usually the case, its net effect is 

known. 

The census and the registration system, if both are 

accurate and timely, thus provide a strong up-to-the-
minute measure of overall population change for a 

country as a whole. This strong time factor largely 

disappears for the estimation of vital rates or net rates 

I of population change for subnational areas since in 

must cases, internal migration is not negligible nor 

is its net magnitude known in post-census periods. 

Therefore, for other than national totals, the vital 

statistics system inherits the time deficiency of the 

periodic census. In certain countries there is another 

serious time-defect in the registration system. In 

these countries vital events are tabulated not according 

to the month or year in which they occurred but 

according to the month or year in which they were 

registered. Since substantial numbers of births may be 

registered years after the events took place, this method 

of compilation may conceal a significant trend in the 

rate. 

‘3. Continuous Population re~”stev - content (medium): The continuous national population register 

based on some form of a national census, continuously 

updated by an input of information from a registration 

system and periodically verified by a census check, 

would be expected to be more complete in terms of 

content than either of the two systems which support 

it. In general, these registers include clear information 

on the fact of a vital event, on the geographic movement of people from residence in one geographic civil 

division to another, and, in some cases, on a few censustype variables relating to population composition. If the 

registers are maintained on a family basis, many 

other items of demographic interest, such as marital 

history and fertility history, can be derived from the 

information on the record. Because of this linking of 

discrete items of information the population register 

can be richer in content than either of its supporting 

systems. In spite of such technical advantages it may 

be noted that the United Nations statistical commission 

has expressed a rather negative opinion of population 

registers	 as a statistical data collecting method.36 

10. Continuous Fpufat{onve@”ster - areal(strong): 

One of the original and primary purposes of the population register is to establish a population figure (or 

even a roster) for small geographic civil administrative units. For this reasofl the fact of change of residence from one local jurisdiction to another is currently 

noted. Hence data on vital events, together with figures 

on the corresponding base population is potentially 

available for cities and small geographic areas. Population registers are often stronger in providing data for 

local areas than in methods for collating such data, except for a few summary figures, into totals for more 

and more comprehensive subnational or national figures. 

Il. Continuous population re~”stw - compositwn 

(weak): Since population registers are periodically revised or verified by some form of population census, 

they could have the same strength relative to data on 

population composition as the census itself. However, 

the current input information from the registration 

system is weak on this type of information and as a 

consequence the continuous register will rapidly deteriorate with reference to its accuracy on ihese variables as the original or revised census data become 

obsolete. Furthermore, the population register collates 

input data relating to the base census information, the 

current registration information, and reported information on migration. The necessity for economical and 

efficient procedures for recording these data tends to 

eliminate from the population registers variables which 

were not essential to their original purpose. As stated, 

these purposes usually have been more closely concerned with local administrative problems than compiling useful national or subnational statistics. 

12. Contimwuspopulation regz”iter - time (strong): 

The continuous population register has all of the advantages of the vital registration system with regard 

to the time factor, and because the base population is 

continuously updated, the system overcomes the disadvantages relating to time which are suffered by the 

periodic census. Therefore from the standpoint of 

measuring current population changes and current 

changes in vital rates, the population register has 

outstanding advantages particularly since this time 

advantage is accompanied by an equally strong area 

advantage. These strong points would seem to indicate 

that the population register method approaches an 

ideal system for measuring current population change. 

However, the method is highly sophisticated and serious 

defects in the system arise from a complex of technical 

and administration problems. The detailed consideration of these problems requires a separate analysis of 

the operational requirements of population register 

systems. 

13. &le re~”stiation system - content (medium): As has been stated above in comection with the 

definition of the statistical methods considered here, 

the concept of the sample registration system is not 

yet precisely defined. If tbe sample registration system 

is, in effect, an integral part of the regular nationwide 

legal registration system then it tends to be limited 

in content to the same items that are included in the 

regular system. Some new experimental data-collection 

procedures which are sometimes referred to as sample 

registration schemes are more in the namre of a series 

of successive interview surveys of the same sample 

areas. To the extent that this is so, the procedures can 

have a wider content scope than the conventional registration system. Because it is on a sample basis and 

therefore more economical than a complete system, 

there is no intrinsic reason why a semple registration 

system could not expand its content werage to some 

extent even if the system is closely r “ed to the regular registration organization. 

15 
14. Sample re~”stration system - area (medium): 

The sample registration system is appropriate either 

for collecting data for a small defined area, such as a 

minor civil administrative unit, or for larger geographic 

areas such as states or provinces or for the territorial 

expanse of a whole country. For example, the Indian 

sample registration scheme~4 is planned for the whole 

country, but it is initially Mng put into operation in 

only some of the states and within some of these states 

it has also been operating on a more intensive basis 

than in others with increased sample sizes in selected 

regions. 

A sample registration system, whether it covers 

only a small local area or the total country, is of 

course based on data collected from a number of small 

geographic sample units. This exposes the system to 

some technical and administrative problems related to 

reallocation of data on a residence basis. Another problem arises in the assumption that there is correspondence between the population in an area and the vital 

events recorded in the area. 

15. Sample ve~”stration system - composition 

(weak); The sample registration system suffers from 

the same limitations as the conventional registration 

system in the restriction of the number and scope of 

items on the registration document that permit an 

analysis of the information on vital events according to 

composition groups of the population. Unless established 

as an independent and duplicating system in addition to 

the regular system in the sample areas, the sample 

system will k constrained somewhat by the underlying 

legal orientation of the conventional system. 

16. Sample re~”stiation system - tim~ (strong): 

Since under a registration system the data are collected 

currently and since under a sample system the total 

volume of data need not be large, the time aspect of the 

sample registration scheme is one of its strong factors. 

However, the gross number of vital events becomes 

meaningful as a measure of population change only when 

it is converted into rates by being related to a correct 

population base. Therefore a sample registration system, by itself, has some of the same time deficiencies 

as the conventional registration system. That is, it is 

most valuable at the time of, or for a short period 

after, the regular census. However, if the primary 

purpose of the sample registration system is to provide a current measure of change in birth and death 

rates it need only cover a population of sufficient size 

to bring the sampling errors down to a size consonant 

with the magnitude of the rate changes it is desired to 

detect. Under this sampling scheme, it therefore becomes administratively feasible to take ad hoc or regular periodic censuses of the sample areas as frequently 

as required to establish a satisfactorily accurate population base. 

17. Sample interview survey - content (strong): 

The feasible content coverage of the sample interview 

survey as a method of measuring population change 

and related factors is one of its strong aspects. Since it 

is on a sample basis, the volume of field and processing 

work may he held at a manageable level so that there 

is no intrinsic limit to the scope of items determined by 

work volume considerations. Usually there are no legal 

or policy considerations, as in the case of the census or 

the vital registration system, that restrict the scope of 

the items included. In this type of data-collection process it is so easy to add items that this may turn into 

somewhat of a disadvantage rather than an advantage. 

The Population Council has recently compiled a collection of fertility survey schedules15 that contain a bewildering array of topics. In an attempt to introduce 

some order and standardization into fertility survey 

practice the International “Union for the Scientific Study 

of Population has prepared several recommended lists 

of topics but even the recommended core list contains 

over 80 items and subitems. The census and the vital 

statistics system may be too weak on item coverage 

but the items that are included in these official procedures have had the advantage of many decades of 

appraisal, testing, and international recommendation.h 

This sifting process has barely begun for items included in fertility surveys. 

18. Sample interview surveys - area (medium): 

With regard to area coverage, sample surveys may be 

considered to have medium or variable strength. The 

sample investigation can be focused on any defined 

small area that may be of interest in evaluating population action programs or, as in the case of the Indian 

National Sample Survey,37 the area coverage may be 

nationwide. While adjustable in this way, surveys in 

practice have one feature that usually limits their 

utility for area analysis. If designed for nationwide 

coverage, a sample survey cannot be designed to also 

yield estimates for states or provinces without substantially increased costs. If designed to produce estimates for a single state or province, the survey cannot 

yield estimates for subprovincial units without large 

increased costs. Ileoretically, of course, a nationwide 

survey could - be designed to produce national, state, 

and local estimates, but in this case the operation 

would become so massive that it would approach censuslike magnitude and would necessarily take on some of 

the census deficiencies with regard to content coverage, 

time required to produce results, and the gap between 

successive surveys as dictated by budget considerations. 

hworkon in~rnational standards for mortality classi fication was 

initiatsd at the first International Statistical Congress in 1853. The 

first international recobrmendations for a population census were adopted by the International Statistical Institute in 1872. 

16 
19. Sample intevview survey - composition 

(strong): A sample interview survey if properly designed can produce population estimates in the proper 

categories for which it is desired to compute vital 

rates and other population-based proportions. Since 

there is no rigid limit on adding content items it is 

practical to produce population estimates for the desired composition factors. This factor is therefore one 

of the strong features of sample interview surveys. 

20. Sample inteniew suvvey - time (strong): The 

time factor is a strong aspect of the sample interview 

survey. Due to the relatively small volume of documents, 

data processing can be completed without serious delays and aside from budgetary and administrative considerations sample surveys can be repeated at frequent 

intervals. Of course budgetary and administrative considerations are also the only barriers to a frequent 

repetition of a census, but in the case of sample surveys 

these considerations are not so restrictive because of 

the much smaller cost in funds and other resources 

required for sample investigations. 

21. Panel longitudinal - content (medium): The 

panel longitudinal followup study method potentially 

can cover a wide variety of topics or items. With a 

relatively small number of persons comprising the 

panel there is no strict barrier to the addition of a 

wide variety of topics to the scope of the data collected. 

This apparent freedom is somewhat restricted by the 

longitudinal character of the method which then results 

in a sequence of observations on the same items for the 

same person, thus introducing problems of reconciling 

inconsistencies and dealing analytically with a number 

of individual time sequence patterns. Because of these 

difficulties data collected as longitudinal series are 

often analyzed merely as successive cross-section 

studies. The analytical difficulties also make it impractical to study the interrelationship of a great many 

items. The wide possible subject coverage of this 

method is more apparent than real. 

22. Panel longitudinal - area (weak): One of the 

fundamental problems with the panel followup method 

of study is the difficulty of tracing and identifying 

members of the panel that move from their original 

place of residence during the course of the period 

of the longitudinal study. A related difficulty is to 

identify the fact of death for panel members or to 

record the fact and reason for other disappearances 

from the roster under active study. These problems 

are greatly increased as the geographic scope of the 

panel study is extended. Longitudinal studies have 

many intrinsic operational limitations even if confined 

to a small geographic area where intensive intermittent observations of the panel are possible. For a 

study extending over a large area the longitudinal study 

is an impractical data-collecting method. 

23. Panel longitudinal - composition (weak): This 

method of study is weak with regard to its potential 

for analyzing population change and related factors by 

various components of the population. The area limitations and the necessary limitation on the overall size 

of the panel is not likely to permit a panel with adequate 

representation of many different population components 

in adequate size for analysis. The method however permits the collection of a wide range of items and within the above restrictions the data can be analyzed by 

population composition. A major difficulty arises, 

however, as the study proceeds over a longer period 

of time. Even if the panel at its initiation contains the 

adequate or desired elements for a study of variables 

by the composition of the population represented, the 

gradual erosion of the panel by death and other losses 

produces doubt on the validity or representativeness of 

any analysis by the initially established categories. 

24. Panel lo~”tudinal followup - time (medium): 

The necessity of periodic observation of or interviews 

with the panel members introduces a time delay in this 

method which does not exist, for example, in the sample 

registration system where the recording of vital events 

is continuous. However, because the panel is likely to be 

small and located within a compact geographic area the 

interval between successive observations need not be 

long. The analysis of simple even’s, such as the number 

of births, requires no great tim’e for processing, but the 

analytical difficulties of interpreting a set of complex 

series means that the method is not likely to yield quick 

and clearly interpretable measures of population 

change? 

25. Demographic measurement laboratory - content (strong): As defined, the demographic measurement laboratory ia a contiguous area for which a variety 

of methods are used on a continuing basis to determine 

the demographic characteristics of the population resident in the laboratory. Accordingly the subject scope 

and content of the data collected can be extensive. The 

content coverage can include not only- typical census 

and vital statistics items but also many other variables concerning factors related to population change. 

The danger may lx? that the lalwatory concept encourages the collection of a plethora of subject items 

many of which may be of tangential value to the main 

issues under study. 

26. Demographic measurement lubwatory - avea 

(weak): A concept involving data collection by any 

method as an intensive process in a defined and limited 

area has the major weakness of an area limitation in 

the interpretation and application of its results. The 

laboratory concept, implying in effect a continuous 

intensive field investigation, is not feasible on a nationwide basis. Conceptually it is possible to visualize a 

network of such laboratories distributed throughout a 

country to adequately represent the heterogeneous 

spread of a nationts population. It is entirely possible 

that this area disadvantage could be overcome in this way 

and perhaps at a cost of more or less the same order 

17 
of magnitude as the annual cost of the decennial census 

program or of the vital registration system. However, 

cost and other operating data for an illustrative demographic laboratory are not yet available to allow an 

evaluation of the practicality y of such a national network 

of laboratories. ~ven if the laboratory idea were extended to a national network, it would still be inadequate 

to provide data for other political subdivisions such as 

states. Experience and the intrinsic concept of demographic laboratory indicate that the area factor is a 

weak aspect of the laboratory idea. 

27. Demographic measurement .Movatory - compos%on (strong): Since the laboratory concept visualizes the frequent periodic census—a current collection of data on vital events and various ad hoc surveys— 

the system has the potential of permitting detailed 

analysis of population change for various components 

of the population. The restrictions on these analytic 

possibilities do not arise from the feasibility of col­

* “. f.. GOVERNMENT PRINTING OFFICE -1 S70 - .3s6-244 P. 0.41 

lecting information on the variables of interest, but 

rather from the fact that the area limitation of the 

laboratory itself may mean that the population resident 

in the laboratory does not include an adequate number 

of the various population component groups which are 

of interest. Nevertheless, if the laboratory site is 

selected with this matter in mind, its usefulness in 

permitting the study of population changes for different 

components of the population is a strong factor. 

28. Demographic measurement laboratory - time 

(stiong): The time factor is one of the strong aspects 

of this concept. A frequent census, with current collection of information on vital events, involving a 

relatively small volume of data, permits a rapid collection and analysis of current material with little 

intrinsic timelag. The time delay in noting population 

changes can be reduced as much as desired so that it 

is limited only by administrative adeptness in the statistical operations. 

18 
OUTLINE OF REPORT SERIES FOR VITAL AND HEALTH Statistics 

Public Health Service Publication No. 1000 

Series 1.	 Progvatns an4t collection procertuves.— Reports which describe the general programs of the National 

Center for Health Statistics and its offices and divisions, data collection methods used, definitions, 

and other material necessary for understanding the data. 

Series 2.	 Data evaluation and methods research. —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. 

Series 3.	 Analytical studies. — Reports presenting analytical or interpretive studies based on vital and health 

statistics, carrying the analysis further than the expository types of reports in the other series. 

Series 4.	 Documents and committee reports. — Final reports of major committees concerned with vital and 

health statistics. and documents such as recommended model vital registration laws and revised birth 

and death certificates. 

Series 10.	 Data from the Health Intevviero SwweJ. —Statistics on illness, accidental injuries, disability, use of 

hospital, medical, dental, and other services, and other health-related topics, based on data collected 

in a continuing national household interview survey. 

Series 11.	 Data frotn the Health Examination Suvcey. — Data from direct examination, testing, and measurenlent of national samples of the population provide the basis for two types of reports: (1) estimates 

of the medically defined prevalence of specific diseases in the United States and the distributions of 

the population with reqpect to physical, physiological, and psychological characteristics; and (2) 

.malvsis of relationships among the various measurements without reference to an explicit finite 

universe of persons. 

SeYies 12.	 Data fvom the Institutional Population Surveys. — Statistics relating to the health characteristics of 

persons 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. 

SeVies 13.	 Data fvom the Hospital Dischavge Suvuey. —Statistics relating to discharged patients in short-stay 

hospitals, based on a sample of patient records in a national sample of hospitals. 

SeVies 14.	 Data on health resources: manpowey and facilities.—Statistics on the numbers, geographic distribution, and characteristics of health resources including physicians, dentists, nurses, other health 

manpower occupations, hospitals, nursing homes, and outpatient and other inpatient facilities. 

SeVies 20.	 Data on mo~tality. — 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. 

Sevies 21.	 Data on natality, marviage, and divovce. — Various statistics on natality, marriage, and divorce other 

than as included in annual or monthly reports—special analyses by demographic variables, also 

geographic and time series analyses, studies of fertility. 

Sevies 22. Da&a fvom the National Natalit>~ and Mortality SuYLJejs. —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 of 

Jife, characteristics of pregnancy. rt. 

l:or a list of titles of reports published in these series, write to: office of [nfornlation 

N.{tioll.11 Center for IIealth Statistics 

U.S. Public [Iealth Service 

Washington, D.C. 2020~