menage - Millennium Development Goals Indicators

Italic type: The "Code for Current Estimates of Total Population"given above describes in abbreviated form the method used in constructingthe estimates of total population for a current year which, inthis Demographic Yearbook. relates to 1968. The quality of theseestimates can be ascertained roughly by the application of certaincriteria based on their origin.To begin with, reliable estimates can be defined as those having theirorigin in a census of population (coded A); those based on a samplesurvey representing the majority of the population (coded B); and,provided the total population is under 1 000 persons, those obtained byannual administrative counting of population (coded C).A second criteria of reliability is the "method of time adjustment".Time adjustment by the population-register method (coded a), or by thebalancing equation method (coded b), is considered acceptable, providedthe components ofthe adjusting factors are adequately accountedfor. "Adequate" accounting is defined for this purpose as combinationsof (a) and (b) with 1 and 2. "Less good" time adjustment includesupdating by assumed rates of population growth (coded c); no updating(coded d), and method unknown (coded .. ).Applications of the above criteria results in "reliable" and "lessreliable" estimates and in the tables, the latter are distinguished fromthe former by being set in italic, rather than in roman type.Evaluation of time series of population estimatesThe code described above was designed primarily to evaluate thereliability of a particular estimate of total population for a current date.However, since there is usually a certain consistency in the manner inwhich countries prepare their population estimates from year to year,the code has some relevance also to the estimates for other recentyears. Therefore, it was decided to assume that the quality of the entiretime series was the same as that of the latest official estimate. 1 2Hence, the time trend of estimates is set in italics if the code for theestimate in the latest year column is "less reliable". No attempt hasbeen made to split the series even though it is evident that the datanow considered reliable are of varying degrees of reliability, and that.in earlier years, many must have been considerably less reliable thanthe current classification implies. Thus it will be evident that thismethod overstates the probable reliability of the time series in manycases. It may also understate the reliability of estimates for yearsimmediately preceding or following a census enumeration.Evaluation of estimated age distributionsEstimates of the age/sex distribution of population may be constructedby two major methods; (1) by applying the specific componentsof population change to each age/sex group of the populationas enumerated at the census; and (2) by distributing the total estimatedfor a post-censal year proportionately according to the age/sexstructure at the time of the census. Estimates constructed by the lattermethod are not published in the Demographic Yearbook.Among those published, estimated age/sex distributions are categorizedas "reliable" or "less reliable" according to the method ofconstruction established for "total" population. Hence, the qualitydesignation of the total figure, as determined by the code, is consideredto apply also to the whole distribution by age and sex, and the data areset in italics or roman type, as appropriate, on this basis alone.Although the accuracy of the age statements at the time of thecensus has been studied and the results of a number of censuses havebeen rated (see p. 9) no attempt has been made to project thisevaluation to the post-censal estimates by aqe and sex.12 United Nations estimates are preferably constructed according to the samemethod as was used for the latest official figure. However, lack of the propertime-adjustment components often dictates the use of a less desirable method,in which case the quality code for the time series is determined by the latestofficial estimate, irrespective of its time reference.VITAL STATISTICSFor purposes of the Demographic Yearbook, vital statistics havebeen defined as statistics of live birth, death, foetal death, marriage anddivorce. This is in accord with Principle 201 of the United NationsPrinciples for a Vital Statistics System' 3 which defines the field of vitalstatistics as encompassing these, as well as statistics of adoptions,legitimations, recognitions, annulments and legal separations.The factors which affect international comparability of vital statisticsare much the same as those which must be considered in evaluatingthe variations in population statistics. Differences in geographic andethnic coverage of the data; variation in the reliability of the statistics,as measured by completeness of registration and of reporting inhousehold surveys; non-sampling and sampling errors and othersources of bias; diverse tabulation procedures; differences in statisticaldefinitions of vital events-all these may influence comparability.Standards for the improvement of vital statistics in respect of theseand other factors have been set forth in the Principles for a VitalStatistics System.'4 The utility of these international recommendationshas been further developed, and their application to national situationsexplored in the Handbook of Vital Statistics Methods.' 5 The Handbookalso discusses in detail the sources of error in vital statistics which areoutlined below, and reference should be made to it for further details.Reference should also be made to the Handbook of HouseholdSurveys'6 for a discussion of the effects of sampling and responseerrors in the interview-type inquiry.13 Principles for a Vital Statistics System; Recommendations for the Improvementand Standardization of Vital Statistics (United Nations publication, SalesNo.: 53.XVI1.8). p. 6.14 Ibid.15 Handbook of Vital Statistics Methods. (United Nations publication, SalesNo.. 55 XVII 1).16 Handbook of Household Surveys. (United Nations publication, Sales No..64.XVI1.13) chapters II and IX.SOURCES OF VARIATIONFragmentary coverage-geographic and ethnicDespite the fact that the obtaining of statistics of live birth, death,foetal death, marriage and divorce has been given priority in the UnitedNations recommendations, the availability of such statistics varieswidely.'7 This is due in part to lack of uniformity and universality innational legislation. In some areas, registration is compulsory only forbirths and deaths; in others, it is compulsory for only a small part of thepopulation (e.g., European or non-indigenous population) In stillother countries there is no national provision for compulsory registration,but only municipal or state ordinances which do not cover theentire geographic area. Still other countries have developed a registrationarea which comprises only a part of the country, the remainderbeing excluded for reasons of inaccessibility or because of economicand cultural considerations that make regular registration a practicalimpossibility.Examinations of the tables will show that the availability of vitalstatistics from civil registers is particularly spotty in Africa. They areonly slightly more available for much of Asia and parts of LatinAmerica. In these continents, coverage is uneven and the statisticsgenerally incomplete and unreliable. This fragmentary coverage is animportant limitation to international comparability. It should be noted,however, that estimated rates obtained by the sample survey methodor from analysis of census returns are becoming increasingly available.Although such estimates cannot be considered an adequate substitutefor reliable registration statistics, they do provide valuable interiminformation and they are induded in the tables.17 For an analysis of the regional availability of birth and death statistics, seePopulation Bulletin of the United Nations, No. 6-1962 with special referenceto the situation and recent trends of mortality in the world. (United Nationspublication, Sales No.: 62.XII1.2) and Population Bulletin ofthe United Nations,No. 7-'-:1963 with special reference to conditions and trends of fertility in theworld. (United Nations publication, Sales No.. 64.XII1.2).10