FAO STATISTICAL DEVELOPMENT SERIES
CONDUCTING AGRICULTURAL CENSUSES AND SURVEYS
FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
18.1 The agricultural census is one of a countries' largest statistical undertakings. It is also a costly operation which finds its value in the wide range of data uses, not only for policy decision-making but also for private use and general knowledge, etc. Providing timely and accurate data is a matter of great importance. The dissemination process should be well organized and discussed with primary data users within the census committee, as mentioned in Chapter 2. Traditionally, the main access to results is offered through published reports. Nevertheless, new methods of dissemination exist which will undoubtedly be more readily available with the advance of new technologies. One of the duties of the unit responsible for dissemination of data is to make the best use of both traditional and new dissemination methods.
18.2 Although the tendency is to plan to provide a wide range of results, the importance of the time factor should be kept in mind because the usefulness of statistical information decreases in proportion to the length of time taken to provide it. Those responsible for the census should always search for the optimum compromise between an ambitious dissemination programme and a quick but definitive release of the main results. In fact, the dissemination should be seen (and thought of) as a dynamic process between these two extremes.
18.3 Along with the preparation of a work plan for the various census operations, a work plan and a specific budget should also be prepared for the dissemination programme discussed in the following paragraphs.
Informing the users
18.4 The publicity campaign should have made people aware of the census. Even if the enumeration was conducted on the basis of a sample where only a small fraction of holders was contacted during the survey, other holders, not part of the sample, should be madeaware of the census through the publicity campaign referred to in Chapter 10, Census Publicity. The main purpose of the census publicity programme is to make people aware of the objectives and purposes of the census and to obtain their full cooperation during the field work. Once curiosity has been created in the public's mind, they are expecting and looking for census results. The general public may not fully comprehend the implications and use of the census results, but this is not true of the principal data users, such as agricultural planners, research workers, agro-industrialists, etc. The primary data users keenly await the publication of the census results.
18.5 It is very important to bring to the public's attention data available from the census. The public may not remember having participated in an enumeration which possibly took place some time ago. To implement a new and short campaign of information is best done by orientation toward the presentation of national results: for number of holders, number of livestock, size of agricultural land, importance of the agricultural sector in the country and trends since the previous census, etc. Generally, the media are eager to receive this kind of information and the opportunity should be taken with these messages to make it known that the census dissemination process is now under way. Presentation of census results might be done on radio or television by the Minister of Agriculture or Planning (depending who is in charge of the census organization).
18.6 Opportunities to participate in seminars, conferences, lectures and talks on various media are often offered to census staff to present and enhance the value of information provided by the census and other parts of the statistical system. Such talks, if carefully prepared, are an efficient means of provoking interest for census data. This should be considered as an important part of the dissemination process by those associated with the census.
18.7 The publicity for promoting the use of census results should take into account that the primary users are:
Knowledge of potential users and their use of census data is important, not only for the orientation of the publicity campaign but even more so for planning the dissemination programme, including decisions on the number of copies required of each report and their prices.
The publication plan
18.8 The first document to be prepared should be a catalogue designed to present the publication plan, the date of issue of each report, the price and the size, addresses where they can be bought or ordered, summaries of contents and even order forms. This document should be issued as early as possible and as soon as the publication programme is finalized, and then widely distributed, particularly during the campaign mentioned above. The computer media releases may also be announced as part of the report. These would include raw data, additional tabulations, etc., on diskettes, compact discs, or direct access, as discussed later in the section on other kinds of dissemination. The catalogue is an officialcommitment of the unit in charge of dissemination and a maximum effort should be made to meet this commitment.
18.9 The publication plan described in the catalogue may include the following documents:
The nature and content of these documents are described below:
Preliminary results (report)
18.10 A short preliminary report with advance results should be issued as soon as possible. It may include only selected priority results, mentioned in Chapter 9, showing only totals without cross-classification, and may be only a few pages, usually at national and major administrative division levels. However, advance estimates of some basic characteristics of holdings may be useful to persons actively engaged in the process of planning agricultural development programmes and intimately connected with the formulation of the census operations. There are other groups, like research workers, agro-industrialists, agricultural input manufacturers, etc., who are equally interested in the results of the census.
18.11 To maximize the benefits of the census, the results can be published sequentially. There are certain items of information, such as number of agricultural holdings according to their size, land use, area and production of major crops, number of livestock and poultry, etc., which are very important to agricultural planners and administrators, which should be published as early as possible. The importance of the items will vary from country to country, and, therefore, they should be chosen for advance tabulation in consultation with the Agricultural Census Committee. Because of the time factor it may not always be possible to prepare advance estimates of principal characteristics of the holdings based on all the holdings enumerated in the census. In this case a sample of holdings may be chosen for this purpose and the results released for the country as a whole or for broad administrative areas. The users of such results should be cautioned that such data is preliminary and subject to various sampling errors.
18.12 If the census is based on a sample, advance preliminary estimates for principal characteristics of holdings may be calculated by selecting a suitable sub-sample from the sample chosen for the census. Here also, limitations of such estimates should be mentioned as a footnote so the user is aware of these limitations when using them.
18.13 One way of advancing the release date of census results is the direct reproduction of computer printouts. However, this technique requires a very thorough testing of computer programs for tabulation in view of the need for high quality presentation of tables. It also requires complete editing and validation of data in order to produce consistent and well-balanced tables where all horizontal and vertical totals agree. In practical situations, last-minute changes on final tables are sometimes required. Whatever software is used for data tabulation, final tables can be transferred to word processing or similar software which makes possible final improvements of the table lay-out and last-minute data changes.
18.14 An efficient process for developing quick advanced results is for field supervisors to prepare totals for the most important characteristics at the end of field enumeration as a part of their report. This can be done with special forms, normally one line for each agriculturalholding with totals calculated manually using a simple calculator. Higher-level supervisors should make aggregates for their areas. This procedure can also be applied in the case of sample enumeration, depending on the sample design. Usually it is sufficient to multiply village totals by respective expansion factors. It should be recognized, however, that this manual process is very prone to errors.
18.15 The period for releasing the advance estimates after completion of the field work will be different for each country. It will depend on the strength of the technical personnel and the data processing equipment that is available. However, the period should not be more than a few months after completion of the field work. If it takes longer, the urgent need for census information is left unsatisfied and the practical usefulness of the census is seriously diminished. In any case, the second publicity campaign promoting the use of the census results, described above, should not be implemented before important results are available.
18.16 The majority of users usually ignore the fact that results reported in the preliminary report are provisional and subject to revision. They may even forget that estimates are not always based on data from all holdings enumerated in the census. This should not, however, deter from making such an advance release of preliminary results.
18.17 A general and final report of the census results should be prepared by the professional staff and, if possible, reviewed by experts familiar with the agricultural situation of the country. The report may be issued in a number of volumes, depending on the size of the country and contents of the report; for example on a geographical basis, one volume for each province or, on a subject basis, one volume for land use, another for livestock, another for equipment, etc. The report should not be burdened with technical details but, in addition to numerous statistical tables, it should include information on conceptual, organizational and administrative aspects of the census which might be useful for better understanding and evaluating the data.
18.18 Thus, the final report could deal with the following items:
Some annexes such as census law, questionnaire, instructions, maps, etc., will be included.
18.19 Undoubtedly, a good final report on an agricultural census is a product of a thorough and quantitative knowledge of national agriculture. Sometimes, experts are employed as consultants for a short period to give an appropriate interpretation of census data. In order to make this work possible it is essential to provide sufficient funds in the census budget for the analysis of the census data and the preparation of a good report.
18.20 If the census has been conducted on a complete enumeration basis, obviously with the objective of presenting the census results at the smallest administrative level, producing a census report with such details is a very difficult and arduous task. The report will become unwieldy in size. Moreover, individual users will be interested in detailed data for specific areas only. This is a case where the report might be split into different volumes, each volume serving the interests of different groups of people or localities. This becomes a major issue in large countries. In India, for example, the results of the agricultural census are published in several volumes. The All-India report gives summary results for the country as a whole as well as for individual States of the Union, while separate reports are produced for individual States. The State report presents detailed data for the individual districts. Otherwise, the format of the All-India report and that of individual States is the same.
18.21 No uniform method is suggested for all countries nor whether the census results should be produced in one or many volumes. It depends on the scope and coverage, the size of the country, the methodology followed and the plans to disseminate data. The report should be prepared keeping in mind the users' interest. The size of the report should be such that readers do not find difficulty in handling it and it should not be forgotten that the preparation of a good report requires time and money.
18.22 In Chapter 16, Quality checks and post-enumeration surveys, it has been mentioned that the census methodology which obtains information on some of the items through interview might not be appropriate and the results should emphasize the census methodology used and, thereby, the limitation of the results. This is considered very important, particularly in developing countries as they have few traditions of conducting censuses. It is difficult to suggest an appropriate method of presenting results when it is known that they are subject to significant non-sampling errors. These will depend on the nature of the results and experience of the country. In extreme cases it might be advisable to present the results in percentages rather than in absolute figures. For example, if it is known that there has been an under-enumeration of total holdings for some reason, it will be better to present the number of holdings in different size classes as a percentage of the total number of holdings rather than presenting them in absolute figures. This technique of presenting results will be useful in many situations when the reliability of census results has not been fully evaluated.
18.23 With the current progress in graphic presentation of data, through the use of computers, there is an increasing use of maps to show visually the spatial distribution of various characteristics of agriculture. Different data such as average size of holdings, proportion of agricultural land, main crops, irrigated land, livestock, use of paid workers, etc., can be shown for different administrative (or other) areas on a map using different colours or shades. With modern equipment, production of such maps is simple once the delineation of administrative areas is stored on computer media. Of course, such an atlas can be part of the final report, but because of different (more expensive) printing, and different users (implying possibly a different number of copies required) it may be preferable to publish the atlas separately.
18.24 In some cases there may be limitations in applicability of mapping due to the data collection statistical methodology. As data are shown on maps by administrative (or other) areas in the sense that one area receives one colour or shade, the implication is that sample enumeration data for small areas are not reliable and cannot be shown as estimates. Even in a complete enumeration census, there may be a problem in countries with many large holdings spread across several areas, as data for small areas may not be representative. This means that data on large holdings are attributed in many countries to the area where holders live, maybe in a town, distorting the information on small administrative areas.
18.25 A technical report is aimed at describing in detail how the whole operation has been conducted, the methodology, choices made, concepts and definitions applied, difficulties encountered, possible delays and their reasons, etc., and to use this evaluation for making recommendations for future tasks. A technical report should include an evaluation of problems met, mistakes made and solutions found, and may include many confidential elements. Furthermore, the main purpose is to record past experiences for future internal use; consequently, it may be preferable not to publish but reproduce only a few copies. Taking these factors into account the following approaches might be chosen: to include a summary of technical information in the final report mentioned above; to prepare a separate, more detailed, technical report for public use; and to prepare a detailed technical report including confidential information for internal use only. In any case, without a systematically-prepared report the experiences gained and lessons learned in a census may be forgotten and the organization of the next census may mean a new and independent effort starting from scratch.
18.26 The following guidelines are suggested for preparing this technical report.
18.27 In countries which have achieved a sufficient level of statistical development and of conducting censuses, it will not be difficult to satisfactorily tackle the problem of preparing a detailed report. Developing countries, which have just started developing a proper statistical system and which have limited experience of organizing large-scale census operations, must begin to think of preparing a detailed report on the census work proposed. However, irrespective of the level of statistical development in a country, it should be pointed out that documents on the various phases of census operations must be collected as the work progresses. This approach simplifies the preparation of the technical report and ensures that the salient points and experiences are recorded while fresh in the minds of technical and field staff. It is important to have a continuous recording of important points of the various phases of the census, including the problems and decisions made from time to time to enable the census staff to prepare the report. It should also be added that the tradition of exchanging census reports, particularly between neighbouring countries, can serve a very useful purpose in their improvement. This gives countries with less experience in preparing reports the benefit of the techniques followed by more experienced countries. A wider circulation of reports will also foster exchange of experiences and enhance the improvement of statistical practices in the field of agriculture.
Report on quality checks and post-enumeration surveys
18.28 The need for quality checks and post-enumeration surveys has been emphasized in Chapter 16. Quality checks should be a post-enumeration survey. The work involved should be carried out and finalized immediately after the census is taken. Therefore, it will require special effort to finalize the analysis of quality check survey data in time to permit incorporating the findings in the census reports and in the technical report on census methodology. The report of the quality check survey should be included in the technicalreport on census methodology. It is not recommended to modify census results based on findings from the quality check survey but it should be regarded as a means of evaluating the validity of the data collected, i.e., either to confirm their validity or to present to users the limitation of the data.
18.29 The report on quality checks can also be presented in two parts. The first general part, in addition to presenting data collected, may deal with the design of the quality check; supporting evidence (regarding the quality of data collected in the check); description of tables presented; interpretation of data and their use; and conclusion. The second technical part may contain sections on the purpose of the check; sample, its selection, efficiency studies; method of collection of data; organization of the check; supporting evidence on quality of check data; analysis of errors and biases; suggestions for improvement; problems needing further study; efficiency considerations; and suggestions for the improvement of future quality checks. The appendix to the report might contain the questionnaire, field instructions, instructions for measurement, etc.
Other kinds of dissemination
18.30 With full computerization of census data processing and advances in information technology there is an increasing interest in providing access to census data via computer media rather than providing tables on paper. Changes occur mainly under the following aspects:
UN (1984). Handbook for household surveys (revised edition). Studies in Methods, Series F, No. 31.
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.
US Bureau of the Census (1974). Standards for discussion and presentation of error in data. Technical paper No. 32. Washington DC.