agcensus.htm

FAO STATISTICAL DEVELOPMENT SERIES
No 6
CONDUCTING AGRICULTURAL CENSUSES AND SURVEYS
FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
ROME, 1995

Introduction

9.1 The tabulation plan should be developed in three phases; first, one should identify information which has high priority and which should be released as early as possible. These tables may be preliminary results from manual tabulations of control sheets or obtained by using a subset of the census data; either a representative sample, or a geographic subset.

9.2 The basic tables are those which are designed to be most useful to a large spectrum of national data users. To assist in the creation of an appropriate group of these tables, a check-list of commonly used cross-tabulations is shown later in this chapter.

9.3 Finally, an additive subset of tables which incorporate country needs and priorities can be processed; these tables may either be planned from the beginning or may be added at a later time. During development of the processing for all tables, an agricultural census data base should be designed and used. Additional tables can then be prepared upon request using this data base.

9.4 The field work and processing and dissemination of census data are the two principal components of the census operation and are interlinked. The amount of field work will determine the amount of processing and dissemination. A balance has to be determined between the resources spent on the two components. It has been the general experience that in a well-formulated agricultural census or survey about two-thirds of the total expenditure goes to planning and conducting the field work while one-third is spent on data processing and data dissemination.

9.5 With poor planning it often happens that a disproportionately large percentage of the total budget is spent on data collection and not enough funds are left for processing and tabulation, resulting in either a delay in tabulation while searching for additional resourcesor in part of the data not being tabulated. It must be realized that data collection through a complicated field inquiry is very expensive and if data remain unutilized because they are not processed for any reason, is a waste of national resources.

Talk to the users

9.6 Data users must be consulted during the preparation of the tabulation plan. Considering that the process of organizing an agricultural census may take many years (3 to 6) from the time of formulating the questionnaires until all census reports have been published, users frequently have requests reflecting new government policies, such as additional data on small farms, women's participation in agriculture, etc. It is highly desirable that, as a matter of principle, the tabulation plan, once approved, not be changed because of such requests as these changes will create organizational complications. In some cases resources may need to be reallocated and, perhaps, are not available without additional inputs to the work plan and budget. Flexibility offered by meeting requests mentioned in the section on cross-tabulations or in the section on computer media products in Chapter 18, should meet most additional requirements.

9.7 With electronic data processing and sophisticated data users, one can expect many requests for cross-tabulations; consequently, it is necessary that measures be taken to safeguard data confidentiality, particularly when detailed data breakdowns are made available by size groups and/or small geographic or administrative areas.

Data processing and evaluation

9.8 Data processing is the responsibility of specialized staff and is covered in Chapter 16. Nevertheless, statisticians responsible for census organization should also be continuously involved in the data processing work.

  1. They should provide the tabulation plan including all details required such as description of codes, lists of names of administrative units, expansion factors (if sample enumeration), etc.
  2. They should assist in testing the computer programs prepared for tabulation by providing a special data set for program validation. Specially completed questionnaires may be constructed to verify all possible cases in as few questionnaires as possible. Manual tabulations should also be prepared to check computer printouts.
  3. They should systematically check all the tables for internal and external consistency before they are published. This subject is covered in Chapter 16, Quality Checks and Post-enumeration Surveys.

Amount of tabulation for administrative units and the limitations due to sampling

9.9 With the increased demand for tabulations needed for decentralized planning at the smallest administrative units, users should be aware of the limitations of such statistics specifically when sampling methods are employed.

9.10 Complete enumeration. If data are collected by complete enumeration, it is theoretically possible to tabulate data for the smallest geographic areas. In fact, even rare characteristics of holdings could be presented. The only restrictions occur when limiting the number of pages in the census report and when ensuring that the tables do not disclose confidential data of individual holdings. For example, if data are classified by size of holding for each village, tables may reveal data for large holdings in each village where only one or a few large holdings exist. In many countries there is a legal obligation to treat confidentiallydata on individual holdings and this commitment must be honoured. In some census laws there is a penalty for disclosing confidential data.

9.11 Sample enumeration. In many countries a complete enumeration of holdings may not be feasible because of cost, time, and/or staffing constraints. In sample enumerations the results are subject to sampling error making it impossible to interpret results for data items with only a few observations. The tabulations prepared for the lower levels of administrative units would have to be very limited . The tabulations to be produced for the lowest administrative level would depend on the sampling scheme, sampling variance of characteristics and level of reliability desired. In particular, detailed tabulations of rare items such as minor crops are to be avoided. As a rule of thumb, all tables with a large number of empty cells are to be avoided. Information about sampling errors should be provided systematically for published tables (perhaps, as a footnote); a special chapter may also be included in the reports to describe the effects of sampling on the results.

9.12 A study, either based on past census results or on more recent surveys, would provide a reasonable estimate of the sampling error of major farm characteristics. These would serve as a guide in deciding which tabulations might be prepared for various administrative levels at a desired level of reliability.

Preparation of the tabulation plan

9.13 In setting up a tabulation plan for an agricultural census, consideration should be given to the type of information needed by the country as well as by international agencies. Communications between producers and users of statistics should, therefore, be established early in the preparatory stages of the questionnaire. The importance of forming a group of experts drawn from user organizations for formulating the questionnaire has been discussed in detail in Chapters 2 and 8. This group should involve professionals who know the agricultural economic situation and its problems and who have the expertise to identify data needs. This group may assess past census tabulations and select those to be retained. New data needs should also be presented and discussed. Tabulation plans of neighbouring countries may also be useful. The tabulation plan is planned during the same period as the design of the questionnaire to ensure that items of information needed in the tabulation will be collected and recorded on the questionnaire.

9.14 The agricultural census office should observe and take note of the type and frequency of requests received from various agencies and catalogue the demand and identify data which may not be available from other sources.

9.15 Reference is made in Chapter 10, Census Publicity, to the fact that the objectives, scope and coverage of the census should be widely brought to the notice of the public so that they are aware of the utility as well as the limitations of census results. The public in general and agricultural planners in particular should also be informed well in advance of the census whether it is to be a sample enumeration or a complete enumeration census. This may avoid requests for additional information that arise after field work has been completed. For example, if the census has been conducted on a sampling basis it may not be possible or reasonable to tabulate the data, which an agricultural planner may subsequently request for smaller administrative areas.

9.16 There are several reasons why the tabulation plan should be prepared early and not changed subsequently without important motives.

9.17 The tabulation plan is needed for planning and organizing the data processing. The kind, size and number of tabulations required may influence selection of software and, attimes, even the hardware requirements. However, such decisions have to be made months or sometimes years before the actual work is done.

9.18 Data requirements for lower administrative levels will affect decisions taken on the size of the sample in sample enumeration censuses.

9.19 A number of other census activities may benefit from knowing the tabulation plan, such as planning the manual process of preliminary data collected by field supervisors, computer validation and editing of data, planning the publication programme, etc. In some countries, data processing may be decentralized with provincial offices responsible for data processing and providing the required tables at the provincial level before submission to the central office and preparing any other tabulations required by local authorities.

9.20 After the items of information to be tabulated have been determined and corresponding questions have been included in the questionnaire, the manner of arrangement and presentation of these data into tables for analysis and publication can be decided. One should bear in mind that the table format should be meaningful and significant and easily used by data users.

9.21 When preparing the tabulation plan for individual countries the following should be kept in mind:

  1. The number of priority tables should be restricted in order to make them quickly available to permit rapid dissemination. These tables may include all data collected but with limited cross-tabulations or possibly in different volumes so that the more important data are available very early.
  2. Further analysis should be facilitated by:
    • -providing additional cross-tabulations;
    • -making available raw data to users in the form of a data base (still protecting confidentiality);
    • -making available facilities for the production of special tables requested by users. (In this respect, it can be said that with new developments in computer technology, it becomes less and less useful to print a large set of tables, and more and more useful to invest in a system capable of producing tables upon request.)

Cross-tabulations

9.22 Tabular presentation may vary from country to country. One of the objectives of an agricultural census is to describe the structure of the agricultural sector. Cross-tabulations of different holding characteristics by important classification criteria can show the influence of various factors on agricultural production.

9.23 However, it is a common practice to first determine the items or characteristics to be classified and the groupings to be used and then decide on the various levels of classifications. This work is done with the systems analyst who will implement these requirements.

9.24 The Programme for the World Census of Agriculture 2000 proposes the following 11 classification criteria:

  1. Total area of holding
  2. Total area of agricultural land of holding
  3. Number of livestock on the holding
  4. Purpose of production
  5. Number of permanent workers
  6. Land tenure
  7. Holder's legal status
  8. Size of holder's household
  9. Holder's age
  10. Holder's sex
  11. Irrigation

9.25 Table 9.1 provides a check-list of commonly used cross-tabulations, which are indicated with an x. Columns 1-11 give the main classification criteria; the stub contains various characteristics by category. Category 01, providing data needed to classify holdings by administrative units and agro-ecological regions, is not included in the tables, as all basic cross tabulations apply to all administrative units and agro-ecological regions.

9.26 Careful planning at an early stage is needed to determine which data will be shown at which levels of administrative (or other) subdivisions. This plan can be shown as a part of the table of basic cross-tabulations. In fact, the symbol "x" can be replaced by other symbols indicating administrative level or agro-ecological regions for which the specific cross-classification is planned. For example, the following symbols can be used:
T - country totals only
P - tables envisaged at country and provincial level
D - tables envisaged at country, provincial and district level
A - tables envisaged for agro-ecological regions.

9.27 Furthermore, classification of data by administrative areas should be considered as one of the most important criteria for classification. In a number of national census reports, cross-classifications are limited to showing all data classified by (i) administrative subdivisions and (ii) total area of holding.

9.28 One basic classification presented during census tabulation is total area of holding. Tabulations using this classification would show distribution of land resources and other characteristics of the holding by size, useful as a basis for government policies on agricultural land and land reform programmes. Since size classification has been used in reporting past censuses this classification should be retained for continuity and comparability. Furthermore, attention is increasingly being drawn towards operators of small holdings and toward holdings where the holder is female, with a number of studies and projects aimed at providing assistance.

9.29 Total area of holding, as it relates to production or rate of productivity, has limitations because total area of holding includes those areas not used for production. Another possible classification of holdings is by area of agricultural land. This classification has a direct advantage over that based on total area of land. Total area of agricultural land is more directly associated with farm inputs and with production.

9.30 Obviously, in holdings where livestock is more important than land, numbers of livestock (type depending on the country) is a good measure of size of operations.

9.31 Classification by purpose of production is intended to show data separately for holdings which do/do not utilize the marketing structure. Similarly, classification by land tenure and by legal status of the holder is intended to make possible the comparison of data between land owners and tenants, and between household farming and cooperatives, state farms, corporations, etc.

Table 9.1 - Cross-tabulations check-list
Characteristic headingsHoldings and characteristics of holdings to be classified by
Total area of holdingTotal area of agric. landNo.of
livestock
Purpose
of prod.
No of
permanent
workers
Land
tenure
Holder's
legal
status
Size of
household
Holder's
age
Holder's sexIrrigation
1234567891011
Category 02 - General characteristics
Holder's legal statusx--xxx----x
Use of hired managerx--x-------
Other economic activitiesx--x-------
Purpose of productionxx--xxxxxxx
Category 03 - Demographic characteristics
Holdings by size of holder's householdxx---x--xx-
Holders & members of their household by sex & agex----x---x-
Holders & members of their household by educationx----x---x-
Holders & members of their household by marital statusx----x---x-
Category 04 - Employment
Holders and members of their households economically active by age and sexx--x-x---x-
Holders and members of their households by main occupationx--x-x---x-
Holders and members of their households by type of work (permanent, occasional)x--x-xx--x-
Holdings by number of permanent workers (members of holder's household and hired)x--x-xx--x-
Holdings hiring permanent and occasional workersx-----x----
Hired permanent workers by sex and skilled or unskilledx-----x----
Category 05 - Land and water
Number and area of holdingsxxxxxxxxxxx
Number of parcels by size of parcelsx---------x
Tenure of landx---x--xxxx
Land usexx------xxx
Land by irrigationxx---x-----
Land under shifting cultivation by year clearedx-------xx-
Category 06 - Crops
Major temporary cropsxx-xxxxx-xx
Other temporary cropsxx-x-xxx-x-
Major permanent cropsxx-x-xxx-xx
Other permanent cropsxx-x-xxx-x-
Use of fertilizersx--x-x---xx
Use of pesticidesx--x-x---xx
Use of high yielding crop varietiesx--x-x---xx
Category 07 - Livestock
Holdings by livestock production systemxxxxx-xx---
Holdings by number of livestock (for each relevant kind of livestock)xxx-xxx-xx-
Livestock by sex, age and purpose (for each relevant kind of livestock)xx-xxxx-xx-
Poultry (for each species)xx-xxxx-xx-
Category 08 - Machinery and equipment
Number of stationary power-producing machinery by source of supplyxx-x-x--xx-
Use of other agricultural machinery by source of supplyxx-x-x--xxx
Category 09 - Buildings and other structures
Use of non-residential buildings by tenurex-xx-----xx
Area and volume of non-residential buildings by purposex-xx-----x-
Category 10 - Other activities
Number and area of forest treesx--x--x-xx-
Fishery activities and kind of aquaculture installationsx--x--x-xxx

9.32 Different measures of size of agricultural operations are often classified by number of permanent workers (a measure of labour inputs) and by size of the household (a measure of food requirements in subsistence agriculture).

9.33 Classification by age and sex of holder makes it possible to evaluate the effect of these two factors on farm productivity, adaptability of holders to new technology, etc.

9.34 Irrigation is an important concern in countries where there are competing needs for water resources and increased agricultural production is dependent on, or is utilizing, irrigation.

Presentation of the tabulation plan

9.35 In order to be useful the tabulation plan should be clear and comprehensive. The classical presentation is to prepare "dummy tables" in a condensed form for all data to be tabulated. A dummy table is prepared in the size and form of the table planned for publishing, except that it contains empty cells. An example is shown in Table 9.2.

Table 9.2 - Example of a dummy table
"Number of holdings by total area of holding and by purpose of production"
Purpose of production Number of holdings producing mainly for home consumption Number of holdings producing mainly for sale TOTAL
Total area of holding
All holdings with and without land


Holdings without land


Holdings under 0.5 hectare


0.5 hectare and under 1


1 hectare and under 2


2 hectares and under 5


5 hectares and under 10


10 hectares and under 20


20 hectares and under 50


50 hectares and under 100


100 hectares and over


9.36 A table is always a collection of figures inserted in cells. Care should be taken to produce legible tables (not too many cells on many pages, for example) and to document them as follows:
TITLE : UNITS: xxx

B
Total
A


















Total

Source:

Footnote:

TITLE: the title must at least identify (required)what is reported and according to which criteria. Example (note:row characteristic appears first):
Number of units reported by size of A and by type of B.
UNIT: identifies the unit of measurement (optional)for the numbers in the table; examples are US$, hectares, kilograms, (kg.), etc.
A,B:classification variables or codes (which may be sub-classified).
SOURCE: indicates the source/agency which (required)provided the data. Example: Census of Agriculture of Swaziland (1988).
FOOTNOTE:contains special information about the data in the table; for example, sample survey.
TOTAL:aggregate values for columns and rows (may appear before or after individual column or row data).

Frame 9.1 Table presentation

In this dummy table, basic data referring to "holdings by purpose of production" are distributed by an example of classification of total area of holdings. A complete set of such dummy tables required to describe the tabulation plan would engage the same space as the final report. Some economy of space can be made considering that presentation of basic data and classes used for cross-classification (size classes in the dummy table given as an example) need not be repeated in each dummy table.

9.37 A way of condensing the presentation of the tabulation plan is to show separately:

  1. All basic data (e.g., number of holdings by purpose of production).
  2. Classes for each of the planned classification criteria (e.g., size classes used in Table 9.2).
  3. Table of basic cross-tabulations (see Table 9.1).

9.38 It is irrelevant whether basic data are shown in the heading and classes relating to classification criteria in the stub of the table, as shown in the dummy table above, or vice versa, although there may be some advantage in space economy and computerprogramming, to show basic data in the stub and classes for classification criteria in the heading. Similarly, all data classified by use of one specific cross-classification criterion can be shown in one long table, as is done by some countries. Some guidelines for presentation of tables can be found in Frame 9.1.

9.39 In summary, it should be stressed that the tabulation plan is one of the most important documents in the census preparation and organization process. A major effort is required to prepare it. Once it is prepared it should seldom be changed unless mistakes are found and even then, it is necessary to verify that adequate resources are available to undertake the new activities. If the tabulation plan is changed for some reason, all users mentioned above, internal and external, should be informed.

Suggested reading
FAO (1987). Microcomputer-based data processing: 1990 World Census of Agriculture.
FAO (1995). Programme for the World Census of Agriculture 2000.
UN (1980). Principles and recommendations for population and housing censuses. Statistical papers, Series M, No. 67.

UN (1982). Survey data processing: A review of issues and procedures. NHSCP technical study.
UN (1992). Handbook of population and housing censuses: Part I, Planning, organization and administration of population and housing censuses. Studies in methods, Series F, No. 54.