Agricultural census
 (or census of agriculture) can be defined as a large-scale, periodic, statistical operation for the collection of quantitative information on the structure of agriculture. The word "census" implies a complete enumeration of all agricultural holdings. However, by extension it can be conducted by a sample enumeration, provided the sample is large enough to generate sub-national data ( see the "Programme for the World Census of Agriculture 2000").

Agricultural holding
 (or holding) is an economic unit of agricultural production under single management comprising all livestock kept and all land used wholly or partly for agricultural production purposes, without regard to title, legal form, or size. Single management may be exercised by an individual or household, jointly by two or more individuals or households, by a clan or tribe, or by a juridical person such as a corporation, cooperative or government agency. The holding's land may consist of one or more parcels, located in one or more separate areas or in one or more territorial or administrative divisions, providing the parcels share the same production means utilized by the holding, such as labour, farm buildings, machinery or draught animals. The requirement of sharing the same production means utilized by the holding, such as labour, farm buildings, machinery or draught animals should be fulfilled to a degree to justify the consideration of various parcels as components of one economic unit.

Area frame
 is a sampling frame wherein the sampling units are portions of land, called segments (see Chapters 6 and 7).

Area measurement
 refers to the operation of measuring the size of fields (i) on the ground, using measuring tapes and other instruments such as compass, clinometer, etc. or (ii) using remote sensing (aerial or satellite) images.

Census committee
 is an inter-ministerial or inter-agency committee consisting of high-level personnel with main responsibilities consisting of the overall planning and direction of the census, in cooperation with and/or subject to the review of the census coordinator (see Chapters 2 and 4).

 refers to the legal obligation of the census staff not to reveal the individual holding data to anyone, neither in the form of raw data nor in the form of tables which may permit disclosure of data for individual holdings. Obligation to respond is often linked to and legitimized by confidentiality as a guarantee for the respondent (see Chapter 1).

Continuous harvesting
 refers to crops which are harvested continuously throughout the season, such as carrots radishes, sweet potatoes, etc., or crops which are standing in the field more than a year, like sugar cane. The estimation of their production has to include all the harvest during the year (see Chapter 14).

 describes the universe of units to be enumerated; it can include rural and urban areas. Under predefined thresholds, in physical terms or in value, very small holdings may be excluded from the census.

Crops cultivated simultaneously
 refers to the practice of cultivating two or more different crops simultaneously on the same field or plot. If crops grown simultaneously are temporary and permanent crops together, they are called crops grown in association. Otherwise they are referred to as mixed crops (see Chapter 14).

Data coding
 refers to the operation where original information from the questionnaire, as recorded by enumerators, is replaced by a numeric code required for processing. Typical examples are when names of crops, livestock, farm machinery, activities, etc. are replaced by a unique number (code) or when data expressed in local units are converted to a standard unit. The modern trend is either to enter the complete answer or to use precoded questionnaires and leave the problem of local units to enumerators who are expected to enter in the questionnaires data ready for processing (see Chapter 17).

Data editing
 refers to checking (manually or by computer) the general credibility of the data with respect to (i) missing data, (ii) range tests, and (iii) logical and/or numerical consistency. Examples could be: (i) non-response (e.g. age of the holder not reported); (ii) improbable or impossible entries (e.g. yield is hundred times higher than normal, etc.) (see Chapter 17).

 is the universe, or a list, of all units or elements for which data are to be collected. For the purpose of agricultural censuses and surveys the frame may be defined as a list of all agricultural holdings (see Chapter 7).

 in respect to computers refers to the machinery such as central processing unit, disk storage, printers, etc., as opposed to the programs (software) that are written for its use (see Chapter 17).

Hired manager
 is a civil or juridical person who takes technical and administrative responsibility to manage a holding on a holder's behalf. Responsibilities are limited to making day-to-day decisions to operate the holding, including managing and supervising hired labour. Wages may be paid in cash and/or kind. A hired manager who shares economic and financial responsibilities, in addition to managing the holding, should be considered a holder or a joint holder.

 is a civil or juridical person who makes major decisions regarding resource use and exercises management control over the agricultural operation. The holder has technical and economic responsibility for the holding and may undertake all responsibilities directly or delegate responsibilities related to day-to-day work management to a hired manager.

 see agricultural holding.

 concept is based on the arrangements made by persons, individually or in groups, for providing themselves with food or other essentials for living. A household may be either (a) a oneperson household, i.e., a person who makes provision for his or her own food or other essentials for living without combining with any other person to form part of a multi-person household, or (b) a multi-person household, i.e., a group of two or more persons living together who make common provision for food or other essentials for living. The persons in the group may pool their incomes and have a common budget to a greater or lesser extent; they may be related or unrelated persons or a combination of both. Households usually occupy the whole, part of, or more than one housing unit but they may also be found living in camps, boarding houses or hotels or as administrative personnel in institutions, or they may be homeless. Households consisting of extended families that make common provision for food or of potentially separate households with a common head, resulting from polygamous unions, or households with vacation or other second homes may occupy more than one housing unit.

 is a term used in data processing indicating replacement of individual data which are either not consistent or missing (see Chapter 17).

Land use
 in agricultural statistics refers to land classification according to the agricultural holders' concepts of use i.e., arable land, pastures, etc. (see the "Programme for the World Census of Agriculture 2000" for detailed classification).

List frame
 in agricultural statistics consists of a list of villages or enumeration blocks and a list of names of agricultural holders with information required for locating them for the purpose of enumeration (see Chapter 7).

 are animals such as cattle and sheep which are kept on the holding or otherwise for agricultural production (see the "Programme for the World Census of Agriculture 2000").

Nomadic livestock
 refers to animals kept by households with no permanent place of residence who are forced by natural circumstances, such as scarcity of water and pastures, or because of climatic conditions to move from place to place. The enumeration of such holdings presents special problems (see Chapter 14).

Pilot census
 is a "dry run" for the main census but on a limited scale. It is aimed to evaluate all aspects of the census operation. It usually takes place some months before the census (see Chapter 13).

Post-enumeration survey
 is a small-scale survey aimed at evaluating the accuracy of the data collected during the census. It provides valuable information for dissemination (see Chapter 16).

 are usually small-scale exercises for evaluating specific aspects of the census during the preparatory phase (see Chapter 13).

Primary sampling unit
 is the first level of sub-division of the population, created by selection of a part of the population for further sub-sampling. These may be villages or area blocks which may be sub-divided into segments (see Chapters 6 and 7).

 is the means of informing the public of the purpose of the census and ensuring cooperation of the holders during the enumeration process. All kinds of media may be used for the publicity campaign (see Chapter 10).

 is the document used by the enumerators for recording the data. Its design is one of the most important operations of the census process (see Chapter 8).

Raw data
 are data on the questionnaire provided by the respondent or measured by the enumerator; such data are not yet reviewed or processed or ready for use. They are normally treated as confidential.

Sampling frame
 can be defined as a list of sample units that: (a) includes all (100%) of the population of interest without duplication, (b) provides a clear cut means of identifying each sample unit, and (c) arranges these characteristics so that probability sampling can be done efficiently (see Chapters 6 and 7).

Sampling unit
 represents elements or groups of elements of the universe under study, which can be selected in the sample. There may be sampling units of different levels (see: primary and secondary sampling units), the lowest level being the element under study, i.e., agricultural holding (see Chapter 6).

Satellite imagery
 describes the images provided by satellites (SPOT, LANDSAT...) and sometimes used for the cartographic preparation (see Chapter 5).

 refers to the list of items for which data is to be collected.

Secondary sampling unit
 is the second level sub-division of the population (ultimate level in the case of two-stage sampling) which may be agricultural holdings or area segments, intended for sub-sampling (see Chapter 6).

Shifting cultivation
 is a land utilization method; a particular piece of land is cultivated for some years and then abandoned for a period required to restore its fertility by natural vegetative growth; it is then cultivated again. The distinguishing feature of shifting cultivation is that neither organic fertilizers nor manure are used to retain soil fertility (see Chapter 14).

 consists of programs that control a computer and its peripherals as opposed to actual machinery (see Chapter 17).

 refers to a subdivision of the universe under study into homogeneous areas for sampling purposes, called strata. In each stratum separate samples are taken and separate estimates are made (see Chapter 6).

Time reference
 is a point in time or a period of time to which the data collected refer. A point of time may be either a specific date or day of enumeration. A period is used for reporting the activities, such as employment or production, and refers usually to an agricultural year (see the "Programme for the World Census of Agriculture 2000" for time reference of individual census items).

 is a portion or a sub-division of land which is under single management. It is either a whole holding, an agricultural or non-agricultural part of a holding. Tract is determined, therefore, by definition of a holding and by boundaries of a segment. A holding is composed of one or more tracts (see Chapter 6).

 is a chart identifying all specific activities of the census in a time frame (see Chapter 3).