Symposium
2001/33E 1 August 2001
English and French |
Symposium on Global Review of 2000 Round
of
Population and Housing
Censuses:
Mid-Decade Assessment and Future Prospects
Statistics
Division
Department
of Economic and Social Affairs
United
Nations Secretariat
Statement from France *
Guy Desplanques **
CONTENTS
A. Strategies to promote
greater involvement by stakeholders in the conduct of censuses
B. Strategies for selecting
methods for theCompilation of
sociodemographic data
C. Use of new technologies for
census operations
D. Continuation of
census-related activities during the period between censuses
E. Identifying and resolving
problems of census maps
F. Are post-census surveys
worth the trouble?
1.
In France, statistical projects are the subject of
systematic consultations. To lead these consultations, France has established a
National Council for Statistical Information (CNIS), which provides a forum for
producers and users of public statistics and for discussion of all statistical
survey projects. Where appropriate, CNIS gives its opinions on the
justification for and utility of surveys. The Council also discusses the
modalities of dissemination of census results. Another body, the Approvals
Committee, issues opinions on the methods employed: it gives its views on
whether the methodology used is likely to produce the expected results. Lastly,
in compliance with the laws governing the public’s right to privacy,
statistical projects are referred to the Commission Nationale Informatique et
Libertés (CNIL), which is an integral part of the public statistical system and
gives its opinions on questionnaires and on the processing and dissemination of
data, while maintaining the confidentiality of the data.
2.
The decision to conduct a census is currently made
by decree:[1] the proposal is therefore not debated in Parliament nor is there any
public debate on it. Consultations on a census take place at different stages: during
their preparation, the draft questionnaires are submitted to the various
administrations and discussed in CNIS. CNIL also gives its opinion. The
question of the dissemination of data is also extensively discussed, especially
given the need to reconcile the demands of users (local collectivities,
companies, researchers) seeking information that is as detailed as possible in
geographic terms with the need for confidentiality, which is advocated by CNIL.
The National Institute of Statistics and Economic Studies (INSEE) is also
sensitive to the need for confidentiality, since the Institute would like to
see data-collection exercises take place under proper conditions.
3.
Communes are very important partners in French censuses.
Since there are no municipal registers in France, censuses first of all
establish the legal (official) population of communes. Communes also
participate in the collection of data: census takers are recruited by the
mayors of communes. In the smaller communes, these are often full-time officers
of the commune. This means that the census is closely coordinated with the
Ministry of the Interior, which has overall responsibility for the communes.
France, moreover, has more than 36,000 communes, half of which have fewer than
400 inhabitants. This dispersion creates conditions not found in any other
country and creates difficulties for the organization of the census.
4.
In selecting the questions to be asked in a census,
INSEE follows a number of quite simple rules. First of all, the operation must
be simple in terms of the questions to be put to the population. The
documentation is therefore limited: the housing questionnaire is four pages
long and the individual census form occupies the two sides of a size A4 sheet
of paper. Selection from the demands of the different organizations seeking to
introduce new questions is made under this constraint. A second concern is to
ensure continuity—in other words, to ensure that no important or sudden changes
are made to the questionnaires. In the discussions aimed at resisting pressures
to increase the number of questions, the fact that individuals themselves
complete their census forms is also important: the questions must be simple and
easy to understand. The results must also be easy to process. In France, the
special value of a census compared with other elements of the statistical
system is that it compiles local data. At the national level, numerous polling
surveys are carried out. Administrative sources are concerned mainly with
specific fields and the information gathered cannot be applied to the
individual level.
5.
The outdated nature of census data constitutes a
significant problem, particularly since the census dates are not known in
advance. Data cannot always be used beneficially in exercises conducted prior
to all the arrangements being put in place.
6.
This is one of the main justifications for the
current rolling census project, which should make available each year
comprehensive data that are less than three years old and without any increase
in the average annual budget allocated to the census. The project will rely
more on administrative sources that are used to identify annual trends, while
the rotating method relies on the collection of data in a given area every five
years.
7.
Increasingly, INSEE is subcontracting some of its
tasks, either because these tasks require specific skills or in order to reduce
the backlog in its workload and not delay the results. These two reasons are
valid for the census. Data-processing bureaux were used for the first time in
the 1982 census: the small staff of INSEE and the rules governing recruitment to
the public service precluded the work from being done internally within the
time limit provided, given the other activities carried out by INSEE.
8.
In 1999, INSEE began to optically scan documents.
This option was based on financial considerations, taking into account the
risks inherent in using a technology that up until then had seldom been used on
such a large scale. One of the major problems associated with the use of
subcontractors has been respect for confidentiality, since personal census
forms are being entrusted to outside firms. It is essential to guarantee the
security not only of the premises where the data are processed but also of the
documents during their transportation. This question may in future pose
significant legal problems. The size of the contract for the optical scanning
of data means that it is now necessary to invite tenders from European firms,
thereby running the risk that documents may be processed in foreign countries
and making it difficult to verify compliance with the norms governing the
confidentiality of data.
9.
In the 1999 census, for variables that were
collected in word form, INSEE made extensive use of automatic coding after the
wording was scanned. This procedure represents an important source of savings
in terms of both resources and quality, insofar as it ensures greater
uniformity of treatment.
10.
In France, the interval between two censuses
varies. INSEE is required to consult with budget officials before selecting a
date for the census. This is not helpful to the preparations for the census,
since there is little advance notice as to when the next census will take
place. The average intercensal interval (seven to nine years) is not conducive
to the proper exploitation of the data compiled. On the one hand, it is so long
that little thought is given to the census that will follow the one currently
under preparation. It is long in terms of the mobility of staff, a policy that
has been favoured by INSEE for some years now: nearly all supervisory staff
would have changed in the intercensal period. It is too long also in terms of
computer applications: materials, infrastructure and software evolve rapidly
and it is necessary to start again from scratch or very nearly with each new
census. It should be noted, however, that for the past 25 years INSEE has been
using software for the processing of census data in the tabulation phase, in
the absence of software that might be more efficient in all phases.
11.
On the other hand, the interval is too short to
introduce major changes in areas such as the modalities of data collection and
the elaboration of questionnaires, especially if these changes would have
outside implications. Little time is available for testing to be carried out.
In 1999, for example, a question was added which cannot now be retained since
the reply cannot be processed. However, it is by no means certain that a longer
period of preparation would always prevent this type of difficulty.
12.
Given that censuses represent one of the rare
sources of data for long-term analysis, it is sometimes felt that not enough
care is devoted to archiving because of the lack of resources and also because
the importance of this essential task has not been recognized.
13.
Up until 1990, cartography was first and foremost a
production tool used to prepare maps that facilitated the work of census
takers. The work involved in preparing these maps was therefore limited, taking
place as it did just before the census. It was done largely by hand and relied
on maps supplied by the property tax services.
14.
With the introduction of geographic data systems
and the development of map-making software, the need for detailed geographic
information rapidly increased, particularly since decentralization gave
expanded powers to local collectivities.
15.
INSEE therefore turned to digitized maps, at least
in the larger communes (generally communes with more than 10,000 inhabitants,
which cover half of the population of France). This was done for the 1999
census with the tool being used mainly for the organization of the census and
dissemination of the results. Map-making for census purposes is currently
evolving to take account of other needs: geocoding of files containing
addresses, thereby permitting data to be derived from sources other than the
district census.
16.
This trend should continue in order to ensure
greater harmonization between the publicly managed geographic systems (in their
design and degree of geographic detail). Under these conditions, managing the
geographic infrastructures is now a task separate from carrying out the census,
even though it has remained within the population department. In particular,
management will be an ongoing activity. In future, however, the census will not
be a mere client of cartography. It will also be a supplier using the
information obtained in its data-collection campaigns.
17.
On two occasions in the past (1962 and 1990), INSEE
has conducted a post-census survey. The survey was initially designed to
measure the rate of omissions and double counting, but was also used to measure
the quality of the replies obtained through the deposit and withdrawal method,
as compared with data collection by a census taker. As regards their
comprehensiveness, these two types of survey had rather similar rates. In 1990,
the rate of omission measured was 1.8 per cent, while 0.7 per cent of persons
were wrongly counted twice.
18.
At a practical level, the conduct of post-census
surveys creates significant problems. Since there is no database of the housing
stock in France, the sampling frame can cover only one area. In 1990, INSEE
used the area sampling frame that had been established for the European
workforce survey and its survey covered approximately 20,000 dwellings. Such a
sample already represents a large survey and requires substantial resources
that are difficult to make available at the precise time when the staff of the
regional offices of INSEE are heavily involved in completing the compilation of
census data. Problems also arise because of the movement that occurs in the
interval between the census and the survey: in one month, nearly 0.7 per cent
of dwellings change occupants. Moreover, there is no assurance that the survey
will cover the entire population, even with experienced census takers: problems
of physical access to buildings and problems of dual residence also arise.
19.
The value of the survey lies not only in the fact that
it establishes a rate of omission or of net omission for all of France. In
addition, it provides rates that are later differentiated according to zone so
that the data can be corrected, if necessary. An area sampling, such as the one
conducted in 1999, does not yield results for districts or populations of
negligible size. Such a situation was never envisaged in France. Under these
conditions, the data cannot be corrected and the survey’s objective is merely
methodological.
20.
Controversy has arisen over the communication of
the results of a post-census survey. While, on the one hand, publication of
errors committed may be viewed as a sign of transparency and provide
information to explain why certain data do not reflect the reality, on the
other hand, it may give rise to feelings of mistrust of the statistics. When
the results of the 1999 census were being presented, the announcement of a
certain inaccuracy in relation to the 1990 survey instead facilitated the
communication of the census results and of the related sociodemographic
analyses.
21.
The census update project again raises but in a
different manner the question of post-census surveys. It underscores the need
to integrate into the system a process to measure quality and results, at least
in the large communes, in which the biases that result from omissions or double
counting will be corrected by the very methodology used.
* This document was reproduced without formal editing
** National Institute of Statistics and Economic
Studies (INSEE), France. The views expressed in the paper are those of the
author and do not imply the expression of any opinion on the part of the United
Nations Secretariat.
[1] There
is currently no legislation providing for the conduct of the census. This
situation will change with the census update project, which is the subject of
draft legislation currently before the French National Assembly.