PART 1 METHODOLOGICAL AND OPERATIONAL ASPECTS OF CENSUS TAKING
1. INTRODUCTION
PART 1 METHODOLOGICAL AND OPERATIONAL ASPECTS OF CENSUS TAKING
1. INTRODUCTION
In the 2010 census round more countries in the UNECE region followed the trend, first started in the 1970s, by moving from a wholly ‘traditional’ approach based on a full field enumeration to alternative approaches to collecting census information in an attempt to reduce costs and improve efficiency. More countries than before now base their census either on information obtained solely from administrative sources or on the combined use of different sources including registers and sample surveys, as a complement or a replacement of traditional fieldwork operations. France adopted a unique ‘rolling census’ approach in which information is collected from a different (or rolling) sample of the population each year thereby enabling a ‘census’ to be created on an annual basis if required. The United States also adopted a new approach for their 2010 Census by collecting basic demographic information in a full decennial field operation (as it is required to do constitutionally) but supplementing this with more detailed information from an annual sample survey.
There were also many innovations, particularly in an attempt to improve the efficiency of collecting information in the field, with a significant number of countries relying on (a) geographic information systems to plan their census geography, (b) internet data collection, and the use of hand held devices and laptop computer to replace (or at least minimise) the use of traditional paper questionnaires, and (c) automatic data capture and coding technologies to minimise data processing errors.
Part 1 of this publication deals with general aspects of census management. These range from the increasing move away from the ‘traditional’ methodological approach to data collection, to some of the key operational aspects related to the census such as: the legislative framework;
communications and publicity; security, confidentiality and disclosure control; and dissemination, documentation, metadata and archiving. Much attention is devoted to the increasing use of technology in all aspects of the census operation, and more focus is also given to the inter-related issues of cost, benefits and quality. Finally, some of the main challenges faced in undertaking modern censuses are summarised, but balanced with the main successes achieved in the 2010 round.
A summary of the main findings is given in this first chapter.
Methodology
The population census plays a central role in the official national statistical system of each country, by providing a reliable estimate of the population, as well as detailed description of the population by sex, age and other demographic, social and economic characteristics, at the national, regional and, most importantly, the smaller territorial levels. When a housing census is conducted together with the population census, information is also provided on the housing arrangements and on their characteristics and amenities.
Population censuses are usually taken once a decade, and in some cases once every five years, but the increasing use of information taken from continuous registers of administrative data (avoiding the need to collect new data each time) means that, theoretically at least in some countries, census-type statistics can be derived even more frequently should there be a need to do so. The continuing trend towards collecting more information by alternative methods is reviewed in Chapter 2.
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Technology
Many of those countries that carried out field operations to collect all or part of their census information reported a variety of other technological aids for doing so (see Chapter 3). In particular, geographic information systems (GIS) – now pretty well established globally - were utilized for the purposes of mapping by more countries than any other technological tool. Some 13 countries reported using such technology for the first time in their field operations.
Over a third of countries that responded to the UNECE survey (18) reported that they provided an internet response option. In the 2000 round only 4 countries did so. However, bearing in mind that such technology was not relevant for those countries adopting a wholly register-based approach to the census, almost half of those countries conducting a field operation adopted an internet solution
The use of laptops or tablet computers by field staff, either for the purpose of recording actual census information or for management support, is also increasing; some 10 countries used such technology in the field in the 2010 round, compared with just 2 countries in the 2000 round.
However, the extent of usage of OCR/OMR technology has levelled of as more countries resort to using automatic electronic scanning of census questionnaires.
The complexity of much of the new software and the infrastructure required for many of the new and emerging technologies go beyond the current technical capabilities of many census agencies.
It was clear in the 2010 round that significant components of the census operation needed to be outsourced in many countries.
Operational activities
In many countries, a specific census act or appropriate regulations are approved before each census (see Chapter 5). In some countries, however, more general statistics legislation includes all the necessary provisions required for the conduct of a population census and/or the production and dissemination of statistical data thereby obviating the need for specific census legislation.
Furthermore in all countries, there is legislation of some form in place that protects the confidentiality of personal information collected for census purposes. Moreover, all but one country reported having a formal policy and/or strategy for ensuring the security and confidentiality of such information. Most countries take measures to protect the statistical confidentiality of published output from the census, with post-tabular methods being more commonly adopted than pre-tabular methods.
Pre-enumeration census tests, pilots or rehearsals were conducted in over 90 per cent of countries while a post-enumeration survey to check coverage was carried out in almost two thirds (see Chapter 4).
All but four of the countries that conducted censuses with a traditional or combined methodology reported that they adopted a strategic communications programme before and during the census operation, and all that did so also carried out an extensive publicity campaign (see Chapter 4).
Dissemination and archiving
Over a third of countries use their websites as the prime medium for static outputs but 30 other countries (60 per cent) use this medium as an additional means of dissemination. Interactive online databases provide the main means of dissemination in 15 countries (see Chapter 6).
Microdata is becoming an increasingly valuable vehicle for the dissemination and manipulation of census data. Well over a third of countries reported that microdata samples are, or would be, available to selected bone fide users, and almost a quarter of countries reported that less detailed samples would be available to all users.
3 The range of metadata to support the census outputs varied considerably between countries.
Most countries produced, or will produce, explanatory notes to accompany the statistical tables, and four fifths reported the production of papers or reports covering the methodological aspects of the census and a wide range of other specific issues. But less than a half reported that they had produced data dictionaries or glossaries of terms used in the outputs. Lack of such metadata is particularly prevalent among countries with register-based censuses.
Only 10 countries adopt a policy of making the individual census returns publicly available for socio-historical or genealogical research after a prescribed period of closure.
Costs, benefits and quality
Census costs have risen considerably since the 2000 round for those countries carrying out a traditional census, among whom the median per capita cost in the 2010 round is USD 5.57 compared with just USD 0.24 for those countries that adopt a register-based methodology (see Chapter 7). The average period of time over which these costs have accrued are, however, broadly similar for each methodology, the mean being 5.8 years for traditional census countries, 5.6 for register-based censuses and 5.0 for those countries adopting a combined approach.
Among countries with a traditional or combined census, field costs continue to account for the greatest proportion of the expenditure, by a large margin.
The introduction of more technology and innovation, particularly the use of online data collection and greater levels of outsourcing, has not only helped to reduce cost increases but has enabled countries to reap more benefits.
The measurement of accuracy was the focus of particular attention in the survey. Almost all countries now adopt one or more methods to measure accuracy. Some 90 per cent of countries carried out an independent post-enumeration coverage check.
The majority of countries (87 per cent) applied editing procedures to enable them to adjust for errors and inconsistencies. Imputation was the most commonly adopted method used by those countries that made adjustments for missing data.
Challenges and successes
Managing timeliness and financial resources were reported as being the most difficult challenges in the 2010 round (see Chapter 8). But other issues such as improving response rates and data quality proved to be almost as challenging – and more so for some countries, particularly those with large field operations.
However, more than two thirds of countries across the UNECE region reported that they had kept within their budget (one of the key criteria for defining a ‘successful’ census) and the same number managed to achieve improved data quality.
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