Symposium 2001/09

6 August 2001


                                                                                                English only


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

New York, 7-10 August 2001













Introductory Note on Census Enumeration *

Alice Clague **




Summary. 3

Introduction. 4

A. Method of enumeration. 4

B. Census contents. 5

C. Enumeration. 5

D. Timing and logistics. 6

E. Hard-to-enumerate groups. 7

F. Unforeseen events that require changes in plans. 7



Introductory Note on Census Enumeration


A wide range of methods of enumeration is available, ranging from face-to-face interviews and mail-out, mail-back questionnaires to electronic responses via the Internet. Some countries use a combination of practices, and a few countries use administrative records for the enumeration process. Choice of an enumeration method is determined by a number of factors, including budgetary constraints; census laws that specify the method; the capacity to print and distribute questionnaires and other materials; other concurrent national activities; weather patterns; security of enumerators; and public attitudes. Cost is also an important factor influencing the decision. The method of enumeration is best chosen early in the census-planning process as so many other operations depend on this choice.


Census organizations have increased demands to collect more information about complex topics. This is especially true in countries where the census is the only source of socio-economic data. Where detailed data are collected on a sample basis, selection of the sample is especially important. Quality is expected to be better if the sample is based on entire enumeration areas.


The choice of census enumerators and the quality of their training greatly affect the success of the data-collection operation. Generally, enumerators have been civil servants, such as teachers; the unemployed; or university students. A good enumerator is one who follows procedures, is able to solve problems in the field, and knows which problems require advice from a supervisor. Training requires well-written enumeration manuals, a clear explanation of concepts and definitions, and hands-on experience during the training process. Performance of enumerators is often improved when payment is based on the quality of their work.


New technology, such as cell phones and e-mail, has improved communication between field units and administrators, and new technology is also becoming available to allow the direct entry of information collected in the field.


Proper timing of the enumeration phase helps to ensure completeness of coverage. For example, in rural areas it is a good idea to plan the enumeration for a time when most people are present for the harvest. Good weather improves the success of enumeration; long national holidays are the worst time. Some groups are difficult to enumerate, and special provisions are needed to identify and enumerate them. Such groups include nomads, refugees or displaced persons, homeless persons and persons living in remote or inaccessible areas or in areas experiencing civil unrest.


Finally, census organizations benefit from having contingency plans for handling unforeseen events. In India, for example, census enumeration coincided with an earthquake. The enumeration continued in most of the country but was postponed in the afflicted region. In Ireland, hoof-and-mouth disease required that the census be delayed for a year.


1.                  This introduction to census enumeration highlights some areas where problems and successes were encountered during the enumeration stage of the census. My role is to set the stage for our discussion of the topic. Owing to its extreme importance for executing a successful census, we have discussed enumeration issues since the inception of census taking. Initially we did not include the item in our agenda. However, many countries mentioned that they would like the current issues in census enumeration discussed at the Symposium.


2.                  We have raised some generic issues for your consideration. Realizing that many of you have recent first-hand experiences in census enumeration, you may want to raise other issues for discussion. We would be grateful if you would raise them as well.

A. Method of enumeration

3.                  We have observed a gradual shift in enumeration practices. Many countries are using multiple options to collect the data ranging from the conventional face-to-face interview to mail-out or mail-back or even electronic responses through the Internet. A few countries are also pre-filling responses in the census questionnaire from their administrative records.


4.                  The criteria driving countries to choose one method or another of enumeration may include any of the following:


·        Budgetary constraints: Over 70 per cent of the census costs are often attributable to enumeration.


·        Authority for decisions: Constitutional provisions or census laws adopted at the beginning of planning phases or administrative regulations.


·        Production capacity: the ability to produce maps (for example, Ethiopia), the capacity to print questionnaires and related documentation based on the availability of technology and the expertise to maintain it. Undertaking these activities elsewhere impinges on quality and retaining control and ensuring confidentiality.


·        Logistics capacity: the bulk movement of materials to respondents and upon completion to the offices where they will be processed. This involves transportation networks, roads, trucks and so forth.


·        Coinciding with other national activities: For instance, scheduling an election when census planning is already under way;


·        Seasonal weather patterns: The best assurance for a census is that it be held in mild and non-stormy weather. For instance, in Mongolia, the census was scheduled for winter in order to ensure that the nomads were stationary. The most recent census was undertaken in a season with unprecedented blizzards.


·        Security of enumerators: Difficulties in enumeration where civil unrest limits security.


·        Public attitudes: Where public sentiment is opposed to the census, the census will require extensive expenditures to ensure cooperation.


·        Other factors: Organizational structure; type of questionnaire and its contents; training programme; content and scope of the publicity campaign; and system of management of records.


5.                  Whatever method one chooses, the decisions on the method of enumeration must be taken at an early stage in census planning, as methods adopted will have direct bearing on these issues. Most of the time decisions are based on a combination of these considerations. However, cost is one of the major factors influencing the decision.

B. Census contents

6.                  Over the last two days we have discussed the various modalities of data-collection tools, such as the use of short and long forms to collect basic socio-economic and demographic information. With the rising need for data, the detail of information collected on socio-economic characteristics has increased considerably and census organizations are being asked to collect more and more data that are of higher complexity and quality in countries where the census is the only source of such data. In turn, this increased demand requires better enumerators and more complex training.


7.                  In addition, in countries where such detailed data are collected on a sample basis, selection of the sample households adds another dimension to the debate. The cost and quality of the census enumeration is influenced by the systematic selection of the sample and the possibility that enumerators will alter the planned approach. Common wisdom is that quality is more likely to be assured if the sample is based on entire enumeration areas. One can also discuss the pros and cons of using random vs. cluster/stratified samples and other related issues.

C. Enumeration

1. Census/survey enumerators

8.                  Enumerators have generally been drawn from the general public. They may be civil servants such as teachers, the unemployed or university and college students. Both the length and intensity of training depends on the quality of enumerators recruited. The qualities of good enumerators are that they are able to work independently, solve problems on the spot and know when to contact supervisors for problems that arise that are outside their scope.


9.                  How can a country select a team of enumerators who can successfully conduct the census enumeration in a given time and avoid major problems during the enumeration period?

2. Training enumerators

10.              The quality of training is dependent on clear and simple enumeration manuals, clear understanding of the concepts and definitions used in the questionnaire by both enumerators and supervisors among other things, duration of training and hands-on experience during the training process.


11.              Generally it has been found that training is most effectively conducted in a cascading manner. That is, a small group is trained and they in turn train a larger group in each region of the country. The timing of the training programme is crucial.  In the ECLAC region a more effective system was found to involve some of the new technologies.

3. Remuneration of enumerators

12.              One of the most expensive parts of the census is the cost of census enumeration. The cost can be rationalized on the basis of the method of remuneration to enumerators. If teachers or other civil servants are used, the direct costs can be reduced. If you hire unemployed or recruit from the general population, resources must be mobilized for hiring, training and paying the new workforce for a longer duration, all of which increase the enumeration costs.


13.              A reasonable remuneration with checks and balances for quality assurance is found to be more effective than a standard payment for each person. Different modalities for remuneration can be a tool for quality assurance if remuneration is based on a method that encourages high-quality work. When enumerators are not rewarded for careful work or perceive that they will be paid regardless of their efforts to obtain responses from each household in their enumeration area, quality may suffer. 

D. Timing and logistics

14.              The proper timing of the census is important in ensuring the completeness of coverage. For example, in rural communities, there are seasons when most of the population returns to rural areas that they consider home to participate in the harvest. This makes enumeration simpler. Long national holidays are the worst time and need to be avoided. Mild weather facilitates census taking.


15.              The logistics of the population census can be mind-boggling at all stages, from printing and distributing the questionnaires to their collection for data capture and data processing. Communication between the census administrator and field units and between the interviewers and supervisors has traditionally been a challenge. A number of authors have indicated that this phase of logistics was improved through the use of cell phones and e-mail communication. Are there other developments that have reduced logistical problems?


16.              The technology of data recording in the field is in the process of change. The direct entry of information collected in the field will enhance data quality and its timely release. 

E. Hard-to-enumerate groups

            People who do not have a permanent residence or those who move regularly were traditionally identified as nomads, refugees or displaced persons, floating or homeless persons who do not have a permanent abode and persons living in remote areas, inaccessible areas or areas experiencing civil unrest. In recent decades, countries have increasingly reported that urban dwellers, young persons, ethnic subgroups and persons living in institutions are difficult to enumerate. Special provisions are described for enumerating such subgroups of the population in several papers presented here.


17.              Two issues—the definition of who should be enumerated and how to enumerate them—need to be discussed. Some examples of groups that are difficult to identify or locate include:

·          Persons on footpaths or camping on the streets or in “vacant buildings”;

·          In Mongolia, children were sleeping in underground tunnels with heating ducts;

·          Persons living in areas where there is civil unrest;

·          Young persons who are away from their parents’ households may be missed;

·          Persons who may be in an area without documentation and wish to remain unnoticed;

·          Refugees or displaced persons who live in camps or with the resident population; and

·          Persons who are nomadic and cross borders between countries.


What impact does a de jure census have on the quality of statistics on the homeless? What is the impact on census costs of enumerating these groups?

F. Unforeseen events that require changes in plans

18.              In planning the census, consideration should be given to emergencies, such as floods, earthquakes, wars and outbreaks of disease. Contingency plans should be made for handling such events. How countries develop such contingency plans and how countries resolve the problems arising from the inability to enumerate the population under such difficult circumstances need to be discussed in the light of recent experiences. Some countries continued the enumeration—for example, India—but postponed it in the region affected by the earthquake; some delayed the entire enumeration, such as Ireland in contending with hoof-and-mouth disease; and other countries adapted in different ways. As Ireland reported, in having to delay its census for an entire year, conducting a census requires not only good planning, but also a modicum of luck.


19.              In conclusion, if there are other issues that affected the quality and cost of enumeration, we would like to hear your experiences that led to difficulties and the solutions that were implemented.   

*       This document was reproduced without formal editing.

**     United Nations Statistics Division, New York.  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.