Field checks on accuracy of popuulation and vital statistics

II I

~J'NITED NATIONS

~CONOMIC I

AND ~ ·

SOCIAL COUNCIL ~

ECONOI\iI.G COT/[MISSIOIJ FOR AFRICA

Seminar on Population Problems in Africa 29 October - 10 November 1962

Cairo, United Arab Republic

Di.atr,' LiMIT'~D

E/CI~.14/ASPP/L. 10

E/CN.9/ CONF.3/L.10 4

October 1962 Original : ENGLISH

FIELD CHECKS ON ACCURANCY OF POPULATION AND VITAL ffilATIsrICS

:'..".,....

62-2610

..(';

.1,',I..:.~:- _,

E/CN.14/ASPP/L.10 E/CN.9/CONF.3!L.10

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•/ I.~I

This Seminar has been organized by the secretariat of the Economic Commission for Africa in co-operation with the United Nations Bureau of Social Affairs, the Statistical Office and the Bureau of Technical Assistance Operations, and the Government of the United

Arab

Republic as host.

I···

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FmLD CHECKS ON ACCQRACY'."OF POPULATION AND VITAL STATISTICS

Prepared ^by the Statistical Office of the United Nations

CONTENTS

Paragraphs

I~ '. ·INTRODUCTION .. .. • • • • ^{i • • • • •} II. . TYPES OF ERRORS ·TOBE ,EXPECTED • • • • • • • • III. :'METHODS OF EVALUATING ACCURACY 'OF E'NUMERAT'ION AND

REGIST~TION

., .,

.0 ., · · .. ., • .. • · · ..•.. • '. · · A:~' Dire··ct· eva.Luat.Lon of population census results •

(a) Ghana

. . · · ^· · · ^. · ^· · · · ·

(b) Greece

· · · ·

(c) Liberia

. . . · · ^{· · · . · · · · · ·}

(d) ~Jigeria

· · · · · · · · ·

(e) Tunisia

. _{· · ·} · · ^{· ·} · ·

(r)

_(g) United States_Yugoslavia

· · · · ·

· · · · ·

9.

Plans for post-censal sample field checks in

connexio~ with

1960

censuses

· · · · · ^· · · ·

Errors revealed by a post-censal sample field check.

/ . ..

^~

1-2

3-5

6-112

10-14 13-17 15-16 17

18-21 22-27

28-47

29 30-32

33

, 3534

36 37 38-43

44-47 48-58 48-55 48-53 54-55 56-58 59-60 61-62 63-73

64

66..

67

68 69 70 71-72

73

..'

· . ..

. . .. ...

... . , . . . ^,

Sample surv~ys · . . .~ . ~ · • · · ..• .' •. · 'Post-ce~s~l .s~mple ~i~i4 chec~' defined •

Fe~tu.:es of a. pos't-icensa.L sampl.e field check •

{a)

S,cope of .r~-enum~ration....:...•. · . • . . • • (b) Timing of. the~e-enumera~ion '. · · •

( c) . Type o~ sampl.e • • • •..•..• . •

(d) Sampling unit · · · ·

(e) Size of· the sample • . • • • '( f) Enume'rators .' .: · ·. . • • · • ·

(g) Informant. · · · . (h) Contents of test schedule • • · ·

(i)

Testing procedures

5.

(a) Errors of coverage

(i)

Under-enumeration . • (ii) Over-enumeration

(b) Errors of content or response

6.

Use of the results of the field check

7.

Limitations of the sample field check

8.

Examples of true post-censal field checks 1. 'R~gisters ~ . .. • . . .~ .' . •

, .(a) . Partial lists • .' .. .' .

·(b) . Population registers . . . .

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. CONTENTS

(cent

1d)

Paragraphs

104-108 109-111 75-111

78-79

• • •• 80-82. :,

• • •• 8.3-84.^{0 . '}

85 . 86

(period .of observation) ..

87-88

89-90 91 92 93 94-95

• • • o '

96-99

.: 100-103 (a) Scope of survey. . . • . . . . • .

(b).

Timing .of

the

survey ( c) Type of sample • • (d) Sampling unit

(e).

Size of the sample . . • • '.. . • . • . • • • • (f), ~nterviewers .. . •

(g) Informant. • . . • •

(h) Contents of the test sc~edule

(i) Testing procedures . • • . . . . Limitations of the field check of v~tal statistics from civil registe~s . . • • . . . • . . • . Examples of field checks o't" vital statistics from civil registers " .' • • • • . . . . • . . Direct evaluation of vital statistics from

civil registers . . . . .

1. Registers . . . • . . 2. Census of population~ • • •

3.

Sample surveys. . . •

4.

Features of a vital statistics field'check.

5.

6.

B.

c.

^{Dt re}ct evaLuat.Lon of househo.Ld sample survey data

on _1?i~hs and deat.hs • • • • • • • • • • 112

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I. INTRODUCTION

'.- !. . '

1: ·~:.D~ilJ.gzecent. yea.rs , ~ncreasing.~mphasis has been. attached.. to the need to

·';evaluate.andp\lbJ-i,.cize. the accuracy of' stat!stieaJ.- se r-Le s , This relatively. new philosophy of admitting the possibility of error and the need (1) to

quantify

it in order to indicate the degree of reliability of the results, (2) to pin-point faulty procedures for cor-rect.Lon when the col.Lect-Lon p.rocedure is repeated, and (;) :.to; cor-rect OJ;' ad.just ',t~e totals in some cases, permeates all fields of

.~:~atistics. .I~. ar~s~s f'rom the recognition that, because of their nat.ure ,

9~ti'st~c's'-'ca:n-:nOt;rior'ne~d ~h~y b~,

¹⁰⁰ per' 'cent accurate ,and provided the

'."~rgin

^{of erro;}

i~'.o~jecti

vely assessed and found to be within reasonable lim1ts ,

. . .. ' . ' ..~. .. . .

the .d~ta ~.Y

pe

.p~consid~rable use for many purposes .

... , . . .' :.. . : ' ...' " . .

2·.

..Application of th.is principle of evaluation to population and vital statlstics .

.^{'.~ ,}..',". . , ' ..~ . .

...Ls

no

^{t . .}ea ay because of the nature of the collection processes involved. For . ,

~~mI?le"

^:the

,~uc~essfultakin~

^{of a} census or national demographic sample survey

. .: " . . . ' . ' " "

de,PeXl~s on a complex Of highly variable components.

It

is, first of all, dependent ona.~Fttion-wideadministrative organization Which' covers every part of the

..; ." . " .. .

count-ry,

It,

is dependent on the quaLity of' performance of a 'large body of mobile

'..~"':' ..:,~ ~~.i...~. " ' . ; . - . . . .

.enumerator-s recruited on a temporary basis. It is dependent; on the ·design of a

.:':~..=.:..r'. .: . . . . .' .. ': ; .

schedult: or' questionnaire which determines the items' on which inf'ormatioriis collected. It i~ dependent on the accuracy

of

a respondent¹s reply t:D thoSe..··

.q~t;_s~ion~. Finally, it is dependent on the quality 'of the data-processing

.·.~:,·~;,-).Ll·:·'.J· .~I'- ,:·:;-.r··..I ..·· ;~r' ' . \'. " ", ••..._. , : . " " _';

.p-~oce·d.~re·s-~-ut;U~ized in the compilation. Similarly; .achievement ofo'complete

. "• • .::':•-'~"J _.~' ^; ~^..;'~fJ.;~ ~~"':^{0' ',' • .' ' .} . . . . •. . .

(100 percerrt )..~.~e,gistration of births, deaths , marr-Iage s and divorces and the'

,..,. '.~: ' ~ ~ . ,

...

comp.~~~,~~~~.^of' re~ie:tble vi"tal statistics :f'roin these records is also a complex

',~ ",' .:..~,~.;'.:' ,: ...:...: <.c."·. ". : : ..".. ; . .

...lJ.Pder~~l~ing.~ ^. ~t ~s dependent on the existence of a nation-wide' network of 'local

...' ~../\~::-;«: 1,'~'. -,\~^{. 1 , ' '.}-~ J~'I e"-:' . ".~' , . . . . ; . . . ' , ' . ' .

registration offices. It is dependent on each office being staffed

by a

competent registrq~:w~o ~~~~,~iews.theinformant. It is _~ependent on the ability' of

this

;, ...:- •,. . ,)... '. . ...: : . I ' . ~ ,. , • .

..re~istra.:r;.. _~.o co.lLect .information on ce r-ta In topics or items whLch characterize the

..~ "..'.' .' ^{~ , .}

vital event. ._:r~ i~ dependent; on the accuracy of the respondents^t answers to the

.:, .' : , . : . ' . • i.. ..'.. ::.-:.., , • ,

quea'tLons, And finally. i t is. d~p'~Jl~ent on the. adequacy of the data-processing ...~~f?cedu:r:~s ut.Ll.Lzed in P/~~ducingthe vital statistics •. Similar considerations

..

~pPJ.,yto data: .on.bf,ryhs,rr~~ deaths obtained from household sample surveys - a

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procedure of data collection whicl;l::q.~sbeen followed in many parts of Africa.

Errors are to be anticipated at every stage of enumeration, registration and stati:stical proceaamg sInce each is

a

product of human endeavour; therefore

procedures must'

be

^{devised to eliminate,} minimize or at least measure, these' errors

at

'ev~i:y stage.

II~ TYPES OF ERRORS TO BE EXPECTED

3.

Errors to pe expected in population and vital statistics can be classified into ~wQ madn categories. The first category comprises errors of coverage',

that

.-;'.:";' .' ." . -..'

Ls, .quantitative errors which have a bearing on the reliability of the' total count

. :'" ~"-; ' . '~ . . .

of persons or events and on the corresponding frequencies fo'r the geographf,c ' ,subdivisions of the country. These are errors of under--enumera'tdon or under-

reg~strationof po~~ationand vital events, that is, deficiencies in geographic

. . . .

or ethnic ,covera~e characterized by failure to include whole groups of'population,

,,;.. ' . ..

inadvertent omission of househo.l.ds or individuals and failure to register

'or

"report

all

vital events. Over-enumeration

or

over-registration is also

a

quantitative error. I~,maY,1?e caused, inter ~, by failure by the enumerator to restrict himself to his particular areas of enumeration or to

follow

instructions for enumerating de facto or de jure ,population as the case may be, as of a specified date; or ^by deliberate or inadvertent registration of a 'vital event in two'

separate registration areas.

4.

The second principal category of errors may be def'Lned iaa errors of content , .'. that is, mistakes in reporting and recording information concerning housebol.de,

inqividuals or events. These are qualitative errors, as contrasted with

quantitative,.~hichmay affect the accuracy of the distribution of population,

" ~ir~~s" deat.ns, mar-rf.ages and divorces by such characteristics as age', "sex, e conomt..

. -, -.

~ct~vity" and the ~ike.

, '

5.

Good. census. survey and registration procedures should provide 'built-in

[email protected]:r.'ds designed to minimize both quantitative and qualitative errors. TO"'help

:, . ,) t:: . -.•:'. .

ensure co:mplete geographd.c coverage in th.e population census, for example, the

t,e~ritory t~ be enumeratied should be well demarcated, with precise geographic

- .

bo:un?-a"ries easily,: identifiable in the field with the help of clear maps. 'Accurate cartographic materials will materially assist in avoiding, the pc)ssib:1.lity

or:·:gB.ps

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or dup~~cation in enumeration. Omission o~ households "Can 'be minimized by a system ~f' .pre-numbe~ingdwellings and checking on coverage by dwelling number."

"Re~eipt ofcensu~ schedules should be controlled by strict supervision at the' enumerat.Lon district level. Similarly, clear delimitation of local registration areas :will assist.;.~!l control of registration completeness. GOod indexes will help to avoid duplicate :.~e.g~~tration. Receipt of statistical reports on each

r~gis~e~ed,eventfrom each local register should be strictly controlled. ContrOl

. f ' (

of the qual~ty of the performance of the enUmerator or the registrar by on-the~

spot verification of an interview will help improve accuracy. Editing and querying of census sched~es,and vital statistics reports for internal consistency, omission of responses, ill::egib11ity and the':iike can improve ,the accuracy of the data.

D~'spi^te these'sb.;:r~'gtlards, ^{which are} part of the normal conduct of a statisticaJ- inqhi'ry:; the popul.a't Lon and vital statistics will reveal inaccuracies which have

#.\ . • ••il .. ~ "

the'ir

source in the enumeration or registration process, Methods for detecting and' meaaurLng'these a.re set forth be.Lov,

III. METHODS OF EVALUATING ACCURACY OF ·ENUMERATION AND REGISTRATIOW

6.

Methods of evaluating the accuracy of statistics may vary in detail according to ,the purpos~s; to be achieved and the resources and degree of statistical'

development of the countries and territC<4"ies involved, but basically' they may

be

classif~ed .Lrrto two types, ,designated for convenience as the direct''and the' indirect methods of evaluation.

7.

Tile Lndfre

ct

method of detecting and, if possible, asaeasang the 'extent of ','omi~9io~1s;_,or duplications in a census , surveyor register is the 'ah81ytlcal

procedure which. cons Lat.s in ecrut tn.Lzf.ng the statistical results tabUlated from"

~h~,:c~nsus schedul.es or the re cords in the register, for plausibility, comparing

::th~se.:,..:¥itl{l:,cor'respondf.ng numer-LcaL data from another time period or from' a . similar geognaphd.c area, and: examining the various distributions for consistency one with the other and for conformity to classic relationships which are known to 'exist between diffe~ent population ch~racteristics from the same universe and between

the~e.and..a theoretical model •

.8., ".The d;irec,t ^.me'tbcd is the more fundamental evaluation procedure designed to

'..

detect errors of coverage and quality. It consists of checking each item on the

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individual ce~s~s or survey schedule or those on the entries in the civil register

, .

against cor'respond.ing data from other current records' "for the same individual^I obbaf.ned ,by.means of an independent data-collection mechanism. Since either'

se't'

of records I!1ay be in error, ^ddscz-epancd.e s must be resolved by further investig:at'1on.

9.

It must be emphasized that both the direct and the Lndf.rec't methods should"be employed in evaluating any type of statistics. Suggested analytical assessment' methods have been set forth in document

E/CN.9/CONF.3/L.ll;'the

direct method of'

"field checks" is described below. Applications to population data are presented , in Part A, and those applicable to vital statistics are given in 'Parts B-C.

A. Direct Evaluation of Population Census Results

10. '~ Iri thi's- sect-Ion , ,the problems, of df.rec't evaluation of popul.ation statistics ..";';'~ ~'-'.:'

are',,'discils,sed wi,th -reference to results of an attempt at 100 per cent enumeratiop.

of:.the populatiQn.,;"To a large extent the methods di~cussedhere are also re'Levarrt to the problem of evaluation of populatio~ data obtained from sample

surveys

though some modifications are required for the latter purpose.

11. As

noted

above, direc~evaluationof the census results consists i:q. matching

e~qh",census report on an individual to a similar record from another source and assessing .the degree of comparability observed. This comparison can 't'a'ke"'place' immediately after, or long after, the ~ensus date so long as it 'utiiizes

'li's'tso"r

persons presumed to be living in tl1.e area as of the time of

the cenSus.'

It 'is ":

obvious that lists originating months or years following the census will make matclJ,ing difficult or impossible because of population mobt.Lity ,

12. "Tndependerrt .recorrts'' for this purpose can come from two sources:' ' the,

commones't and moat ea sLLy obt.alned are the lists or registers of the';population: or

of.~~~~nts tn~~eof which have their' origin' in an administrative procedure not·

: . : ' i ':;',~ . . ' : ',

n~?~~sarily statistical in nature. A second source of independent records is a

S~lIlP+~.survey." that is, the repet I ii"on of the census process on a sample basis and

; • I •~.. •• ~• . : . •

un~e~ .con~itions which seek to ensure that the errors committed in the original enumerat.Ion wi,~l not be repeated and other errors will be minimized.

13.

The relative adequacy of either of the sources

mentioned

above

can

'be' mea~ured

oy; i.,~~,a~ility to provide (1);, an estimate of the completeness of enumeration of"

•'• ..I v,~.,: ,~• _

~o?seho~ds and perso~s for both the country as a whole and for selected geographic

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sUbdiv1"sions:'and (2) a measure or the' accuracy of the cha rac'tez-Lst.Lcs recorded for

individ:uals

in

the

popul.at.Ion, This···crite·~fonwill-"be applied first to registers,

. ^.

to show that they' are rarely adequate for the' comprehensive evaluation envisaged here and that the field check procedure is likely to pe the be~t method •

. .l'~ ; Registers

,::~;!14.· Re'g1sters which have been used to check census schedules are lists of children

enrolled

Ln schools; lists of' registered voters', L, e. electoral lists; registe~s of birtllsarid deaths;

famili~s

^on 'popul.at.Lon registers; lists ()f taxpayers (real estate'tax,income tax, etc.); registers of military recruits, social security .:;~:beneficiaries and so forth.

~.. \

(a) Partial lists

15.Itwilibe apparent at once that, with the exception of the population

register, all of those mentioned are partial,l:i.stsin'that they cover only lImited segrii~rit~ of the population such as school children, voters, taxpayers, new~born

chi.iJi:e~

andvso forth. Because of this limitation, comparison of census

s~hedules

with'these cannot'provide an estimate of the completeness of the census enumeration for the .country as'a whole or'for its major civil divisions, the first prerequisite for adequacy. Nor can an evaluation of quality of response be obtained in most cases because such registers do not usually supply infonnation 'on an.i'ndividual's personal characte rf.stLcs ; The compfetenees with ,which children unde.r .one year of age have been enume rated rp.ay be, evaluated by .co.l.Latd.ng the infants r~PQrted.Ln t.he census with these Lnscr-Ibed in the birth regi:sterand the reliability of response in respect of topics re.la ted to infants can be checked, but this Ls of limited, value.

,.It;>. In additio.n to their limitations in terms of coverageyut must be borne d,n mind ~q.crt

..

tp.e comp.Le'teneas and accuracy of, the pa rt.La.L re,gisteritself is lik~+y to be que at.Lonab.Le , In countries where school enrolment Ls ,~ow,.. t.he list of school.

chf.Ldren will :be def'LcIerrt ; Birth registers t.end to be LncompLe'te in th~. countries which are likely to have poor census enumeration. Electoral registers are notably

inc<?m~~~~e,

in;

m~n,y

count

rdes; ,Tax.:,re.gisters are likely to be deflated while foo,d

..r

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ration regi$ters

t~nd

.to be inflated•

.!/

For this and the otber reasons gi.ven;,

~~oye, it is clear that partial registers are not entirely adequate for asse~~i~g eithe~ the completeness ?r accur~cyof national census results.

(b), Population registers

17.

Population registers, being the most comprehensive of the

registers

mentioned,

••_J_. ..~• •

can serve a~ a better independent source against which to check the qensus

re?9rds,

and indeed they are so used in some European countries. But even in this case, when discrepancies are found in two records, there is no way of knowing wh;i.ch set of data is correct without locating the individual concerned and re~intervi~wing

him. This is usually the procedure adopted. For example, after the count of

1950

in Norway, all census schedules were sent to the office of the local population register to be verified. Discrepancies were followed up in the field" and as a result close to 40,000 persons were added to the.cen~us schedules while some 20,000 were deleted. Thus, a net 'addition of about 1/2 per cent of the total

I " " • •'";. • •

domiciled population was made, a correction of little significance in relation to :. ';t'he whole',' but of importance for 'breakdowns such as age and occupation. The

• • w.

limiting factor on the use of this ,source of records is, of course, the relative -' rarity of reliable population registers.

- - ,

2. Sample surveys

',18.

A second type of .independent record which· can be used for checking

the

completeness and accuracy

of

a census can

be

obtained from a samp.Le:'su"rvey~ SUch a check depends on'_~matching' the documents relating to the same iridi

,jidual

obtadrred from the enumeration arid the survey. Four' groups of documents should

resUli'·'from

this procedure: one group comprises persons enumerated in each of the two"

investigations; a second group consists of persons enUmerated in the census but-not

found in the survey households; a third grOup is the reverse of the second, i~e~,

persons enumerated in the survey households but not f'ound in the 'censusr a , hypothetical fourth group is persons missed "in 'both the census and the survey',

For:exaniple,

Japan, in addition to independent post-censal sample field

cheCkS,

also used the food ration register to check both the

1950

and

1955

censuses of population. A surplus of

0.5

per cent was found in the register for

1950

and

0.66

per cent in

1955.

However, these percentages could not be considered

equivalent to under-enumeration because of the possibility. that they representee duplicate registration in the food register.

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for which some allowance is usually made ; When frequenc~_e_s: for the first three groups are determined, re-examination or.~e-interviewingof .those in groups 2 and

3

must be undertaken to determine .whe~her or not these persons should have been enumerated or surveyed, as the case may be, according to the definitions of the two .i?y~st~.gations.

19.

Th~oretically, any Lndependerrt random sample 'survey of households should yield

. ..~

r~.co;rds adequate for the purpose provLded the sampling frame is such that the unit of enumeration is the same in each type of Lnveat.Lgat.Lon, and that households and

individ~als which failed to be enumerated in one or the other can be identified.

Howeyer, experience with the use of labour force and other surveys for this purpose

~.~,:.~j,c.':£ ':-. . -. .1:~~..

h~s been disappointing, primarily because of differences in the basic defini~i~n~.

used in the two inquiries. Canada, for example, utilized the May

1956

Labour

Force Survey (an area sample of about 1 per cent of the population) to check on the

, .

June

1956

census of population. Documents forthe·sa.me.· househol.d.d'rom each' invest:igation.' were matched .and those households where differences in composition were.found were .re-enumera'ted. Analysis of the resulting data produced an estimate of about 1.1 ·percent under-enumeration at the cen·sus5./ but it was also established that:\differe.nces between the two investigations were due Ln part to 'lack of

cOtnpt:l;:rab'ili,ty in 'the de f'Lnlt Ion of "household". Difficulties of match-ing may 'be .:',:p·o·sed··'also by. the-.·adoption of slightly different 'concepts of the popul.at.Lon to be

·enUme'rated ·in the. household, for example) the enume.ra tIon of popul.atton ·usually

"residing in'the household,at the time of the census and that 'present at the time of the saMple inquiry.

20. The.exp.erience' of Japan' in u.sing th.e Labour Force Survey as a mechanism for:.

che ckf.ngrbne ,l950. popu.Lat.Lon .ceriaue exemplifies another ·disadvanta.g~of.,.usinga.

sample', .survey designed :for .av.pur-poee other than eva'Luat.Lon , Following' ,the'

1950

.' censua-of'<Japan, houcehol.ds- .compr-Lafng the' 10 .pe r cent sample of census returns, used

for 'preliminary tabUlations we.re matched to records .f'r'om the monthly.Labour Force survey)./ Net. under-enumeration was found to be

o. ⁷⁴

per cent, but since the SurVey' was concerned onlY'vti,th persons

14

years of age and over, ,this percentage

· · l . . •

'E..I'

Edward, D. arid Yablonski, E.' "Popul.atn.on Quality Check of the

1956

Census

.or

'Canada'' • 'ottawa,

'1958.

d./

Morita, Yuzo, "An appra LsaL of the population census statistics". Bulletin c;e 1 'Institut International de Statistique, tome

34,3eme

LavraLson ,

1954', '

pp.

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could not be extrapolatedto'thepop{uatjon as a whole since it ,did not reflect under-enumerat.ton throughout

the

early' ages.

2L still another exampl,e

of'~~'

unsucceasf'ul, attempt to use a survey not

':. '. . ,: '.. .i~.::'. . ..': .. ' . ' .

specifically designed for the purpose can be found in the experience of the. United States of America. In

1950,

an experiment was planned to study differences ar~s~ng

"from

different enumerat.Lon techniques, tra.ining programmes and 'questionnaire design as well as to measure, if possib~e, completeness of coverage, age reporting _err~rs, income reporting, and so forth. It was. intended to match returns from the

}prii

1950

Current Population Survey (CPS) to the schedules from the

1

April 195~

census of population, but due 'primarily to procedural difficu.ltie~, the experdmerrt was abandoned in favour of a post-censal sample survey designed specifically,

fd~'

^.

that PUI1?ose.

3.

Post-censal .sample field check defined

22. Since sample surveys. designed to,-obtain current data of one type or another

·:,·Inay:.no.t be strictly comparable to census enumerations in matters of geographic

'~\lbdivisions, unf.ta-of enumeration, type of population included or population coverage, they are not ideally suited for checking the general population census for completeness of cove rage or accuracy of response , A more efficient method is replication of the census under intensive: 'conditions of precision, in a post-censal field check defined as the independent r..::;,~enumerationof a representative sample of

" the population in such a W3.y as to provf.de a reliable measure of (1) the' number of households and persons who were omitted from, or erroneously included in, the' original census count and (2) the 'magnitude and nature of response e.rrors •.

23.

A··true post-c'3nsal field check must:'meet three specific cr-I ter.ia ,':namelY,..>-:.

(1) be Lndependerrtvof' the original 'census; (2) be repres.entative,:o'f··the:.whole~;._

:: -country and all pop'ulatibn' gr'oupa; ..·and (3) involve one-ceo-one matchi.ng<of'.'records. to produce an identical samp.LeTrom each investigation. Independence is

an

espe.cia.lly important criterion: and one. which failed to be achieved in many ·of the' so-ea·J.;led tlr·ie·ld·>checks^tl carriec3_ out in connext.on with several recent censuses. In Ethiop.i·a, for example, a post-ce~sal sample survey, covering every 15th household reported in the. censue of Addis, Ababa~ \'1a.s· conducted Ln

1961.

In the course o.~. ~he orig'inal enumeration, ~he households had been identified by the use of. stickers affixed to

·th-e···i:iving· quarters of each houneho.Ld •.'~h.e" supervisor of each enumeratdon .district

/ ...

E/c~~~~ABrP/L~l~

E/

cN'.·'9/·ooNF~\"5f~lO English ~'~::i j~-~.'

Page

13

'-~.

ws sli1:>s~qrieniiy'-ih~~"a

^list:

(jj'sa.mPiJ 2t rms eh01d

D.limbers :fnreach of' the districts under his

sup~rit~:tO~"and

^the

~-enumerat16n was limited to'

these households. The procedure followed could not uncover omitted. ·b.ouseholdsJ···and,:~':t"n··>this'

..

respect fell

short 'of the Lndependence criterif1n for a J?ost-ceD.sal ffe1a:·~-·check·.· ."

24. ;.

Sinularly, after the

1953

census

in

Ceylon;

a

1 percehil-.L sampie 'verification survey was made to

te~t

the completeness of' enumeration

butthistes~;J-;81.s0~

^wast;

based on a list of households already reported in the

1953

ceneusj 1t~'chU1d not,"

therefore, be considered Lndependenti. nf the census •

.-~~ ~.~.:.!j..; /.' ~'.. .-

25..

Represent.at1veness in respect of the' whole geographt.c area" 'and"all population groups is

a.i.~oanimpdrtant

criterion and one which

ha~'

also f'aiIed/to be achieved '._ by several

inq~ri~~'~b1Ch

^were

unde~taken

as fieid checks •. FbI'

examp~e, ^a

^poSt.;.

.l~~~~.~ ,~uxvey'~as ~de;tak€n

ⁱⁿ

Co~t'aRica

^following

^{the 1950}

censusbut:;tt:::W!l'C

.:r[j~::(.1;i' .:) ...-:: .::::'- :,=:,?,~:::". .: . . ' . . . .. •

confined to :those.parts of the country where enumeration 'wa's tho·'ight:··..to be::1.n&dequate

Re-enumeratl~~'~~~~~ri'ed

^{out in}

¹³⁵

^{of' the}

^3].6 etlume~iil.6n

district'slltl'fj .ihec:ause of the nature of the recheck these were not unifoX'mly distributed throughout the

.:.J,' ' ..:'.~;'" .' . . . . .

country. .~he results showed

6,878

persons

omitt'ed

in

the'135

districts but since

• • • •:,~ :~^..:~ ~^:. . . .; . . .:.~^...-~. ^{: .} . . . " ' . . #- : . . . . ,. .," " . ~.

'.. ~~ app·~are~ .insignificant~ the additional' schedules were simply added to ·thQ~e

' ..•

Ori~~a.Jl; ~um~~ted,

revising the' count. upward

b~' ^0.86

^{per cent. Since it}

^was

r>.!!oot

cOmPr~~si~e,;:;~~ ~bi.~sed, this-l'~

^rl.6t

cbri~id~reda

tI'liepos-t-censal fi:eld.'

.' ...,::·:l.i·. : I."

check. . '. '.. :. ^{,j ,'.}

.. -r;6."

.Sind.:)..arl.Y:, a "post-censal

rieik'~fi~ck ^"b:f tll~--1950

census of' Mexico was :designa

·t~V:·"')··,'.:~!i·. D_L~.:t·~:·,;. C:''- . '.trr .j.,.... ,.. -:: ._ (.. .,: : • . . . .

to cover Mexico City and

18

munic1'pio's

lh'

th~ r'~'st of the Republic where'11111leraey

':~/'~~ ~i~'~~d.

school attendance

anl~ri~fubel/

o'fJ't€achers lbW.!!/ The selected geographic

~y\:^.;.:nr.~r' -.'.~... . '~.: ~.:-."'( ': '. '. '.. ^t' .,',~^{.. , . ( •; •}

areas were not representative of

the

"count'ry~j" Moreover, lacking ·detal1.ed maps.,· the

-:..~::l' ..:ti:» .... .;.t~'.:';':1';: .. '. .' . '~-.'^..>.:"', :'.!,~",^{; .},.~. ^r:» '~.' ^{, . .: ... ' .}

" n j~'i~~~.~q~;.~n...o~.. houaeho.Ida Ln the municipic)"s' was 'made:"f'rom a li:st'of the original.·

..~._^{.• 4 •}..J.:\,.;..-, .• ;..j.'J' . \... ... "., . ' ' . ! :~".i'Lr..;j'..:.: ' . . . , . .: .'_. ,. . ...~.. '

census schedules. Hence the' test was not 'independent of,th·e:·original census·,.texcept in

Mexic~ ~~~y'a~d it thu~ 'ifai'i~

^on

^two

counts ase.

trUepoB'b~'censalfiEili\;:cheek.

IfL~.'. :

27.

In India, the fram.efor

'the'

sample' fi'el'd check on

the' 1951 census

.'.ws'.r.the;

National Register of Citizens which had been transcribed from the original census

:,.~.~_._;..: .' - : ..")- . . ' : ',1'::.;:.L::·.::T; ((.":

-:r 1,~~~b.ed~es. NaturaU-y, with this alone i t would be impo·ssib1.e·to··..find a'-household

:::1.tC.;.r; (:,)(; 1.1:'; !J(' ";;' .>.' .:.:);'.r.··:·);.,. . ' :'1~<. .. iF'

... . .-,

I ...

~ (>.{!1:j:i~~t(;:ritiel

iobf..e'los censos de· Eobl'ac:l6h' d-e

M~xiCQ,

^{by Oscar-MoraJ..e.s Cabanas.}I .

'\ {UN document E/CN\)9!CONF.l/G.10). ·.t.""-·'·;",:,;,·'/l~: ^{·-.'·.T .;,"} ".1:;"

...

^\

E/S~~J:.4f~~p./~

..

^];o,::·..

E/9~:. 9/99N~·~,;II:"7',l.O;,­

English . "

Page

14

r;,~~:. ~s.~_. :omi'~ted~;1Jl .~~ originaJ. ~UID..eJ'a~1<?n".-" ~O,l).gh ~~e test could g1ve, en

. . . .~.. . ..",' ,:~.~ ,''''~.'.'J~ ; ..~. ." . . :, .,: _ . ' .

-iAd1c~iQn<

c.r"

~l.?-~~,e~:~t..:,o.~

.over

o,run~er~~~um,~~t~.9n 9~ peraons within th~'

hQ~olds.,,Tq>~~C~~hOUS~ldS

^,,,hich

h~d'.~~.~~~~:t~e orig1~ai~~~eration'th~'

re-enumeration

~'A:i¥Pp'os~

_{.. -} to:l;nvestigatep,ot onl.Yth.e select.ed_{.. '.'. ' . . . " ,} . " " . ,'. ,,' ':: .~.<:::,!",~,~",:-:

h~~~~old\~t:"

...: .::' . ;--~~

tbh~e'.,B!q.,Ja.o,en:~:,:.~W~~t.lgs,_. to see if_{. .} ".all._{. ~ad}" . " "..been:'"~aught. " ..in ~he ttr8tenur;uera,"tion~. :..^, " " ' ; ' , " " , , " ...

Th1:6,:p~c'ed~eJ.goe,~~. ,Sp~j~,way ~owarq ,independen~e but does, non ensure

repre~~~~t~v;'~~ss•.,

, .

c : .~.:_^..' ~e.atures of a post-censal s~le field check '

.r:2S.-.r: d~rue -po~t~censal,.

o r . " sample field checks 'have .been carrted out or• . • •, . :. . . . " ' i · • .

att~t~

: ' • ^in'

re1ati

veJ,.y.::~~~:~c.ountries

:Q:u.,rtngrecent years;

'the~e ar~' d~scribed

briefl.y 'in'^r'C

pa:Jm~phBi:63~7"~F ^.

The ·tecmniques .used ve.ry in, cletai,l" but the" salient_{. . ' ..}'

t~tur~s ~f

:,;.~~lJ~~h!;:':J:e-enum~~~~9n, ' common to all, .ar~. Q~tl1ne~.1?~ow..

These

in'

effect

'might

. " . . .. .".,: '. ", "." ' .

:DCOt).S,~~t~~e ~.:j.~1~e.;-to~..~J.ann1ng a ~rue .post-~:~stU sample. field check.

'"-)jt~~· .."T.~.~,..;'!'~'! (~l:·i··~:· :,:',:, , : ' " . ., , ,

.'-' ,-. ',_

(~)'

"Sco!>e

'of'

re-enUfuerati6n

'~

.:~..'t'r.1... ' _{.).~ !~1} ;::. .:.~'..r ~J·,T....;.r ;"

<"." : .. . ". ':

29.·'cJJt~~~ti(;)Jf,o,f t1l~

en,J'ire population

is

not desirable nor is

It

neees'sary.

1~':1a-).~0:1h:~~~ir~ple'be(:a~~e.1t.,~W-d

be exeessively

~xpensi

^{ve and the'}

'co~t~ tOgetQer vt~~~,9lJ.rden;.ltnpos·ed

On ,tp..e.PH't>+.ic' in two sp.ccessive censuses,

~akes ioo ~e~':~_t

. '._.-..~ ^{• • •}~^{...'" • • •} ·'<,Io~·.· ^{• •} :j-_.'.~" "~:...~r:"·'~-.Y~I"""'''·' ': r'.t~

7e-enumere:tion prohibitive. It is not necessary because modern sampling" ·t:eohn1·4\1ea

"'LiT1IIalre;it

PQ:s'-Eri.:~4Le;t9·i~er.enumerat~pn1.~a..frac'\f1~~,of

^the

to~alpopu1ationin:~td.~

:.-;;ix);.

:~1m'ln·an.~s.tJ;~~~i-of

^_the

.-~~~s~~~e,;;~~:T~,~~~~~~~~. ,T¥-~;'~;actio~~h~~,(~~

:)1f.{,~j~l'e.,~:::':a!~;·:~8It~.::·~~~lfP··:of.thepqpw.~~.~QP"^"in

order ..

·~ha.t···qu~t1tative measures~"ot'under

~,i~Q;':tWer",~at,ion'IIlay b,~d~rive~

from the results':''''Non-random or

p~ive

~e*"jJP;gqi{jp~~hap~be

·ac.ceptable wllere quantitat.i

~e m~asures

fortheent1re .

j-':1::-:-'c:cctuntry·:or

]l9Pttl?-~i~

are.. not nf

crucia*ilnJ?O~ce,

but the utiii'ty -of

~ng

.a~sample"o:f ",:ne!pop~ation.

for the stu<ly

Q£future.prObl~m8

^indicates

'the '. • _;~

^r<;

desirabil1tY,C?f

s~lectiD:ga

representative

'~ainpl~

^{to beg:tn}

With. - · "

. :~.,:, a~ .:~( . ,. . .f" ..

.. ir _i ,_,.(b ) Timing of the

r~-el1UIlleration

..,;~' .','.'.::':'\.', ^{, ' , ,} .

,0. To be most effective, the re-enumeratit)n should -take i>la.ce"as

'~oon8~'~o'ti81ble

after the conclusion of the original census of the areas which fall 1nt8 the aampl.e

t(j'':b~~~(~~~tfan\fjissed;·.(:~', :·The·"longer:·~the tin.1~:1.nterval, _be~ween,"the.,t~ .~&ati~,

• " ,, , , ..' , . . ~'. , ' . ' ', ••.. ,.~, ,._ • • ;.'~J"'.:," .. '.'~;: ,~,"'.' . ' , ; . "' . ,. . . .

. ./ / . f'·

II ^I

E/CN._14/ASPP·~~o

,..-

EI en. ^9/

^CONF.:3/t.·~

ao

English Page

15

Lot~.::.':.:.r .',_C~'::;';··,'· ^{.':'. . .} . .l.l .... ; ; · , · · , ' , . . . . . . : . '.

the ..._grea~ will be the number "o'f ·d.iffer0j,ces'restilfting :from. births,' deaths,·~'·:

}~.: "., .t " . : . ",', '.'<-:'. ..:1" .•.:<.:, ; " : ''~.. ' '. ",''''';', ^{" I . ' , , ! ' . ' . '}

marr~ages and .migrations which occurred in·"the'inter'VaJ.,·..'and the-::igreater·'the ";;0:'::

C~C'~;~f'1ntrod~c1ng" r~sporise~rr6~~

in" respect 0:["those'1terns ftivColving

,;:.;0;" ; .. ".-.: . ' . :. ~~:':. ^{,_', . .} i,';;' '-/1;'.. '. . . . . '.:" ;.. ":' .... ' " ' . ' . . . . • .

retrospectiop. The more differences"

there

are'between:;"the 'two sets 'of; records·,' ~.

".'.;.:~". .' • . • . . " . • .:. , , : : ' • . " : .;. ' . " . ' ...,.:.:~,,). ^{" ' . •} -~J~'r';'" 00"" • . .~. . . . . .

~l:.l~~o~~ time,'Will be consumed in the subseQ.u.ent··matching and)~'::resbluti'on';pr(ieess=:ri

R~'7~u,m.eratidn

shortly -afte{'tii.-e

ce.n~u.s

^1.rill

t~d"t()

ttdnimlzedlscrepanc1esV:'A :,,:;,

s~~~~~q; thOt{~

not urdmp0rtant,

r~~~on

^'.

fo~ h~V1ng

the post":cerisal',fie1d/

ch~clrhr:,'

soon

'~:d~~'\he'cr:tgi.n~i"e~t.l'n~r~tion i~

that'bYso doing one may' takeadvantage:'n£.i-;- thefieJ,.d

o~gan:lz~i:i~~

already'tn existence i2li-theorlgi.nal

census, ", '

.~ ~...~..,_?: ...~~)"~ ;_,:0:.> .. ' ~: ..j.::::::"~4.:~". . ',' • . :.~. . " . . . , .

31.

Altl;1ough it should tal{e

place

soon

after,·the

census,' the:

re-survey"

·must.·.not .'...,:'

interfe~~~~~the ()~i'~i~al: cens~s'proc~~res.

'Neither should it be cari-iedoiLt:,·

as an integral part of the first enumeraticn, with the same enumerat6r:::asking·b·oth, sets of questtons. Re-interrogation of the informant by the .~ame en~erator1.8 good C~~S:U~ ,p;rect1q~., which will tend tf") enhance the accuracy of

the'·o,lii!nal·

responses,

'; ..' "";"'.'::::.~~':~:.'~·.:.~·':··;.-::':8 :3:Ji.L;'LLf·' " - . : .':.", , ' . . '

but it does APt ~~ncr~ltute F:l i~ldep'eilderit

check'

on 'the accuracy' orthie

enumeration•

.'. : ....[3· ,::'.~:.4::'(':":, : ' " . ,. '... .... ... . , . ' .... . '

'.~.~.:. S~me cC?un~ries

have

.found it'poS-sib'le't6'o'rganize a .

sample:

^survey ,gt~;~about..the

• .' . :.-•.,'..: ; ' . "';', . , ..; ":'.:: ;: i";" ~"" '.... , . '

same time as the. comp.Letie census, in th'e 'course 'of which additi·oha1,·:ttetns.··f,ef:,,:>·;.~·:·.::~r"',,~:

in;f()r~

_<~ tion, not includedill

th~;~el1.

^eraJ.

qti.~sti

onnaf.re, are coIleeted' on a''EeJle.rate

( ; ' . '

sch~a_~q.e,

^{0:1 a}

differc~t;d~'Y,'bY

^an

ieIltireiY'ind~endent

groupof':enumerators'.;'--Wh.n

.' ~~':;,J^{" . 1} " . . . • .: .' .,; i '-' •• ' • . ,_

.s~~h...a sample survey

is

des:fgn.ed to" cover ·the entire'

·terrl--tory

and':w1:th the·i·same',:

>~~~n~~i:on~

^as

t~e 'o~om:pl~t~

^census:i

tth~y

^aJ.so"

~~'~sed

^to giyean asseBsmeritOf',r

t,:p':~, c,9~l.e~~e~~

^'of

enum~ra,t{o~

^and'the

acci.tt~6Y

^ofo : r e p 6 : t ' b l n g ,

at the complete :':,:

;"·~;:,,;,·i:':.;. ·:U:':"':'1.i:.J .:.. . .' ::,.: ..,,: ....: . . . . ' . . . . .

,~::~p.s~~... It,.qa:g. also be used to af;sess the" cost, .speed, adaptability, efficiencYnend

~~C~~Cy ,~/~~mp:u.ng:'~ethod.s

^'in

~omp~'is(')n ~d

th c:6tnplete enumeration.

2/

For most countri,e!3,;c

J~owe~e~,

^'it

'~ll

^{be easte:t:}

t6: _rirgah1i~ a

^Telati

ve1Y

s'imple' satnpJ:ef'i.eJ.d

.'. .' . .'. ;" . . . • ~J!.:..<..~..}. '~.'r" . " . :..:i"~~~ h.'" :... ;. ..~.. . .' .... ....•... .

ch~~~. to follOvl. th~ original enunle:.~atiori

'an<l to

h'8-fle" as'"

·its··

sol'e ·obj;et:tive·

the Gl:!.~C?~i~g'~'f

^the

a~~~~racy

^{0:(the census.} ' , ", ",

:':-! .... ;:.;" ;. ,... .. , . . .~....

~:::~i'T.t'_L·TU;". '.: ~..' ,

33.

Tg.~ore~:t~ally

^it

is'~ossibie

to select a purposivesarnple oi'areas about whi\;-eh

infOrtJl.~tioni.~' part~cul~rlY' d~~irea.

but, "fora.' num:>er' of;rea-sDns mentionedbelo.w.,

.;~.1\;.~. .. ." .../... . ' ..~

• - ' •.,~-"...'t"... •

•..•....j . . ; ' . "

.','/

/ ...

5/ ... ·

^Field checks of tIlis type have been carried out by several countries. In - France,

tne

:post-~ensal fiel.cl _cl1.~ck of the 1954 census was coupled with a

periodical 8u~vey of the employment situation⁰

E/ CN.~4/ASPP!L.lO.

Ej

eN.-9/C.O~·~ .;/L~~:.ib

English~:·l , .;",'< -

Page 16

it is rec:o~~ded ~~~, the .poati-censaf field check be carried out in a well-des1gn@d random

~llJ,si,~; ,~ampl~; smill~o~ghto im:Gitnii:£e

,'cns£ but la:rge'enOughto

':g1ve'~~at'"

least an

eV~l,l~t:lo~

^{nf th'e}

~um~r~t1on

^inthe

c~witry;

^as:a

Wh6i~and1n ^itslDajor

civil

cliv1S~~~si~ceciet~Xmination

^of

quantitat:iv~'measures

^or'

^undez-- and ,

oV~f;~~e~tion'i~

^{one of}

~he1~ortant

object1ves6f the procedure.

'Moreov,er;; ,

the random cluster

'sam.Pi~

YJill'provide"a.

s~ientific

'basis for :future lIivestfgatldns, and,

.ror

thi s' reason

alO~~"1~

^,iwould be desirable to employ random' sampling. Should theJ;'e'be.suspfcfon

of~e~t regio~al v~riabil1ty

1nthe qtialltyof enumeration"";' 100 per

cent"re~en~e~atinl;l

in the areas suspecbed of large errors might have to "

be ~~rri:~Q.... oub.~eparat.e:l;Y, but results' of such intensive checks'mi"ght--th:en' be: _~

... , . .. ., ~ . ~ -..

combfned..wt.t~ ~~~se. of a amal.L sample of the rest of the country

to'

evaluate"" .-.

t ' .