Agriculture Sample Census Survey 2002-2003

Tanzania, 2004

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Reference ID

TZA-NBS-ASCC-2002-v01

Producer(s)

National Bureau of Statistics, Office of Chief Government Statistician-Zanzibar

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Identification

Survey ID number

TZA-NBS-ASCC-2002-v01

Title

Agriculture Sample Census Survey 2002-2003

Country

Name	Country code
Tanzania	TZA

Study type

Agricultural Census [ag/census]

Series Information

This is the third Agriculture Census to be carried out in Tanzania, the first one was conducted in 1971/1972, the second in 1993/1994 and 1994/1995(during1993/95 data on household characteristics and livestock count were collected and data on crop area and production in 1994/95). It considered that, this census is is one of the largest to be carried out in Africa and in many other countries of the world.

Abstract

The 2003 Agriculture Sample Census was designed to meet the data needs of a wide range of users down to district level including policy makers at local, regional and national levels, rural development agencies, funding institutions, researchers, NGOs, farmer organisations, etc. As a result the dataset is both more numerous in its sample and detailed in its scope compared to previous censuses and surveys. To date this is the most detailed Agricultural Census carried out in Africa. The census was carried out in order to:

· Identify structural changes if any, in the size of farm household holdings, crop and livestock production, farm input and implement use. It also seeks to determine if there are any improvements in rural infrastructure and in the level of agriculture household living conditions;
· Provide benchmark data on productivity, production and agricultural practices in relation to policies and interventions promoted by the Ministry of Agriculture and Food Security and other stake holders.
· Establish baseline data for the measurement of the impact of high level objectives of the Agriculture Sector Development Programme (ASDP), National Strategy for Growth and Reduction of Poverty (NSGRP) and other rural development programs and projects.
· Obtain benchmark data that will be used to address specific issues such as: food security, rural poverty, gender, agro-processing, marketing, service delivery, etc.

Kind of Data

Sample survey data [ssd]

Unit of Analysis

Household, Individual

Version

Version Description

Version 01(Public use file for web dissemination)

Version Date

2004-03

Scope

Notes

Topics

Topic	Vocabulary	URI
TRADE, INDUSTRY AND MARKETS [2]	CESSDA

Keywords

TRADE, INDUSTRY AND MARKETS [2]

Coverage

Geographic Coverage

Tanzania Mainland and Zanzibar

Geographic Unit

Clusters

Universe

Small scale farmers, Large Scale Farmers, Community Level

Producers and sponsors

Primary investigators

Name	Affiliation
National Bureau of Statistics	Ministry of Planning and Empowerment
Office of Chief Government Statistician-Zanzibar	Ministry of Finance and Economic Affairs

Producers

Name	Role
Ministry of Agriculture and Food Security	Technical assistance
Ministry of Water and Livestock Development	Technical assistance
Ministry of Cooperatives and Marketing	Technical assistance
Presidents Office, Regional Administration and Local Government	Technical assistance
Ministry of Finance and Economic Affairs	Technical assistance
Food and Agriculture Organisation	Technical assistance

Funding Agency/Sponsor

Name	Role
Tanzania Government	Financial support
United Nation Development Program	Financial support
Department for International Development	Financial support
Japan Government	Financial support
European Union	Financial support

Other Identifications/Acknowledgments

Name	Affiliation	Role
Planning group	Agriculture Statistics Department-NBS	Planning and Supervision of the Survey
Ultec Lawrence Gould		Technical assistance
Scotts Agriculture Consultancy LTD		Technical assistance

Sampling

Sampling Procedure

The Mainland sample consisted of 3,221 villages. These villages were drawn from the National Master Sample (NMS) developed by the National Bureau of Statistics (NBS) to serve as a national framework for the conduct of household based surveys in the country. The National Master Sample was developed from the 2002 Population and Housing Census. The total Mainland sample was 48,315 agricultural households. In Zanzibar a total of 317 EAs were selected and 4,755 agriculture households were covered. Nationwide, all regions and districts were sampled except three urban district (two from Mainland and one from Zanzibar).
In both Mainland and Zanzibar, a stratified two stage sample was used. The number of villages/Enumeration Areas (EAs) were selected for the first stage with a probability proportional to the number of villages in each district. In the second stage, 15 households were selected from a list of farming households in each Village/EA using systematic random sampling. Table 1.1 gives the sample size of households, villages and districts for Tanzania Mainland and Zanzibar.

1.3.4 Questionnaire Design and Other Census Instruments
The questionnaires were designed following user meetings to ensure that the questions asked were in line with users data needs. Several features were incorporated into the design of the questionnaires to increase the accuracy of the data:
· Where feasible all variables were extensively coded to reduce post enumeration coding error.
· The definitions for each section were printed on the opposite page so that the enumerator could easily refer to the instructions whilst interviewing the farmer.
· The responses to all questions were placed in boxes printed on the questionnaire, with one box per character. This feature made it possible to use scanning and Intelligent Character Recognition (ICR) technologies for data entry.
· Skip patterns were used to reduce unnecessary and incorrect coding of sections which do not apply to the respondent.
· Each section was clearly numbered, which facilitated the use of skip patterns and provided a reference for data type coding for the programming of CSPro, SPSS and the dissemination applications.

Three other instruments were used:
· Village Listing Forms were used for listing households in the village and from this list a systematic sample of 15 agricultural households were selected.
· A Training Manual which was used by the trainers for the cascade/pyramid training of supervisors and enumerators
· Enumerator Instruction Manual which was used as reference material.

1.3.5 Field Pre-testing of the Census Instruments
The Questionnaire was pre-tested in five locations (Arusha, Dodoma, Tanga, Unguja and Pemba). This was done to test the wording, flow and relevance of the questions and to finalise crop lists, questionnaire coding and manuals. In addition to this, several data collection methodologies had to be finalised, namely, livestock numbers in pastoralist communities, cut flower production, mixed cropping, use of percentages in the questionnaire and finalising skip patterns and documenting consistency checks.

Weighting

The weight for Agriculture sample Census Survey 2002-2003 found in Technical Report from page (17) to page (20)

Survey instrument

Questionnaires

The census covered agriculture in detail as well as many other aspects of rural development and was conducted using three different questionnaires:
· Small scale farm questionnaire
· Community level questionnaire
· Large scale farm questionnaire
The small scale farm questionnaire was the main census instrument and includes questions related to crop and livestock production and practices; population demographics; access to services, resources and infrastructure; and issues on poverty, gender and subsistence versus profit making production units. The main topics covered were:
· Household demographics and activities of the household members
· Land access/ownership/tenure and use
· Crop and livestock production and productivity
· Access to inputs and farming implements
· Access and use of credit
· Access to infrastructure (roads, district and regional headquarters, markets, advisory services, schools, hospitals, veterinary clinics, etc...)
· Crop marketing, storage and agro processing
· Tree farming, agro-forestry and fish farming
· Access and use of communal resources (grazing, communal forest, water for humans and livestock, beekeeping etc.)
· Investment activities: Irrigation structures, water harvesting, erosion control, fencing, etc.
· Off farm income and non agriculture related activities
· Households living conditions (housing, sanitary facilities, etc.)
· Labour use, livelihood constraints and subsistence versus non subsistence activities
· Gender issues.
The community level questionnaire was designed to collect village level data such as access and use of common resources, community tree plantations and seasonal farm gate prices.

The large scale farm questionnaire was administered to large farms which were either privately or corporately managed. Some data from the large scale farm questionnaire are incorporated in this report, however an in depth analysis of large scale farms is presented in a separate report.

Data collection

Dates of Data Collection

Start	End
2004-01	2004-03

Data Collection Mode

Face-to-face [f2f]

Data Collectors

Name	Affiliation
National Bureau of Statistics	Ministry of Planning and Empowerment

Supervision

Enumerators were trained to probe the respondents until they were satisfied with the responses given before they recorded them in the questionnaire. The first check of the questionnaires was done by enumerators in the field during enumeration. The second check was done by the district supervisors followed by Regional and National Supervisors. Supervisory visits at all levels of supervision focused on consistency checking of the questionnaires. Inconsistencies encountered were corrected, and where necessary a return visit to the respondent was made by the enumerator to obtain the correct information. Further quality control checks were made through a major post enumeration checking exercise where all questionnaires were checked for consistencies by supervisors in the district offices.

Data Collection Notes

Data collection activities for the 2002/03 Agriculture Sample Census took three months from January to March 2004. The data collection methods used during the census was by interview only. No physical measurements, e.g., crop cutting and field area measurement, were taken. Field work was monitored by a hierarchical system of supervisors at the top of which was the Mobile Response Team followed by the Regional Supervisors and District Supervisors. The Mobile Response Team consisted of three Principal Supervisors who provided overall direction to the field operations and responded to queries raised outside the scope of the training exercise. The mobile response team consisted of the Manager of Agriculture Statistics Department, Long-term Consultant and the Desk Officer for the Census. Decisions made on definitions and procedures were then communicated back to all enumerators via the Regional and District Supervisors.

On the Mainland district supervision and enumeration were done by staff from the President's Office, Regional Administration and Local Government (PORALG). Regional and national supervision was provided by senior staff of the National Bureau of Statistics and the sector ministries of agriculture. In Zanzibar the enumeration was done by staff from the Ministry of Agriculture, Natural Resources, Environment and Cooperatives. Supervision was provided by senior officers of the same ministry and the Office of the Chief Government Statistician.

During the household listing exercise, 3,222 extension staff were used on the Mainland and 317 in Zanzibar. For the enumeration of the small holder questionnaire, 1,611 enumerators on Mainland and 158 in Zanzibar were used. An additional five percent of the total number of enumerators was held in reserve in case of drop outs during the enumeration exercise.
1.3.9 Field Supervision and Consistency Checks
Enumerators were trained to probe the respondents until they were satisfied with the responses given before they recorded them in the questionnaire. The first check of the questionnaires was done by enumerators in the field during enumeration. The second check was done by the district supervisors followed by Regional and National Supervisors. Supervisory visits at all levels of supervision focused on consistency checking of the questionnaires. Inconsistencies encountered were corrected, and where necessary a return visit to the respondent was made by the enumerator to obtain the correct information. Further quality control checks were made through a major post enumeration checking exercise where all questionnaires were checked for consistencies by supervisors in the district offices.

Data processing

Data Editing

Data processing consisted of the following processes:
· Data entry
· Data structure formatting
· Batch validation
· Tabulation

Data Entry
Scanning and ICR data capture technology for the small holder questionnaire were used on the Mainland. This not only increased the speed of data entry, it also increased the accuracy due to the reduction of keystroke errors. Interactive validation routines were incorporated into the ICR software to track errors during the verification process. The scanning operation was so successful that it is highly recommended for adoption in future censuses/surveys. In Zanzibar all data was entered manually using CSPro.

Prior to scanning, all questionnaires underwent a manual cleaning exercise. This involved checking that the questionnaire had a full set of pages, correct identification and good handwriting. A score was given to each questionnaire based on the legibility and the completeness of enumeration. This score will be used to assess the quality of enumeration and supervision in order to select the best field staff for future censuses/surveys.

CSPro was used for data entry of all Large Scale Farm and community based questionnaires due to the relatively small number of questionnaires. It was also used to enter data from the 2,880 small holder questionnaires that were rejected by the ICR extraction application.

Data Structure Formatting
A program was developed in visual basic to automatically alter the structure of the output from the scanning/extraction process in order to harmonise it with the manually entered data. The program automatically checked and changed the number of digits for each variable, the record type code, the number of questionnaires in the village, the consistency of the Village ID Code and saved the data of one village in a file named after the village code.

Batch Validation
A batch validation program was developed in order to identify inconsistencies within a questionnaire. This is in addition to the interactive validation during the ICR extraction process. The procedures varied from simple range checking within each variable to the more complex checking between variables. It took six months to screen, edit and validate the data from the smallholder questionnaires. After the long process of data cleaning, tabulations were prepared based on a pre-designed tabulation plan.

Tabulations
Statistical Package for Social Sciences (SPSS) was used to produce the Census tabulations and Microsoft Excel was used to organize the tables and compute additional indicators. Excel was also used to produce charts while ArcView and Freehand were used for the maps.

Analysis and Report Preparation
The analysis in this report focuses on regional comparisons, time series and national production estimates. Microsoft Excel was used to produce charts; ArcView and Freehand were used for maps, whereas Microsoft Word was used to compile the report.

Data Quality
A great deal of emphasis was placed on data quality throughout the whole exercise from planning, questionnaire design, training, supervision, data entry, validation and cleaning/editing. As a result of this, it is believed that the census is highly accurate and representative of what was experienced at field level during the Census year. With very few exceptions, the variables in the questionnaire are within the norms for Tanzania and they follow expected time series trends when compared to historical data. Standard Errors and Coefficients of Variation for the main variables are presented in the Technical Report (Volume I).

Data appraisal

Estimates of Sampling Error

The Sampling Error found on page (21) up to page (22) in the Technical Report for Agriculture Sample Census Survey 2002-2003

Access policy

Confidentiality

Is signing of a confidentiality declaration required?	Confidentiality declaration text
yes	Confidentiality of respodents is guaranteed by section 20 of Tanzania Statistics act number 1 of 2002 Before being granted access to the dataset, all users have formally agree: 1.all identifying information such as the name and address of respondent has been removed; and 2.the information is disclosed in a manner that is not likely to enable the identification of the particular person or undertaking or business to which it relates. 3.not attempt to identify any particular person or undertaking or business; 4.use of information for research or statistically purpose only; 5.not to disclose the information to any other person, organization 6.when required by the Director General, return all documents made available to him to the Director General; 7.comply with the directions given by the Director General relating to the records. 8.every person involved in the research or statistical project for which information is disclosed pursuant to this section shall make the declaration of secrecy set out in the first schedule.

Access conditions

Tanzania NBS considered three levels of accessibility:

1) Public use files, accessible by all
2) Licensed datasets, accessible under certain conditions
3) Datasets only accessible on location, for certain datasets

The dataset has been anonymized and available as a public use dataset. It accessible to all for statistical and research purposes only, under the following terms and conditions:
1.The data and other material will not be redistributed or sold to other individuals, institutions, or organization without the written agreement of the National Bureau of Statistics.
2.The data will be used for statistical and scientific research purposes only. They will be used solely for reporting of aggregated information, and not for investigation of specific individuals or organizations.
3.No attempt will be made to produce links among dataset provided by the National Bureau of Statistics, or among data from the (National Bureau of Statistics) and other datasets that could identify individuals or organizations
4.No attempt will be made to re-identify respondents, and no use will be made of the identify of any person or establishment discovered inadvertently. Any such discovery would immediately be reported to the National Bureau of Statistics.
5.Any books, articles, conference papers, theses, dissertations, reports, or other publications that employ data obtained from the National Bureau of Statistics will cite the source of data in accordance with the Citation Requirement provided with each dataset.

Citation requirements

"National Bureau of Statistics, Agriculture Sample Census Survey 2002-2003(AGRSCS 2002-2003), version 1.0 of the public use dataset(March 2004) provided by the National Bureau of Statistics, www.nbs.go.tz"

Access authority

Name	Affiliation	URL	Email
National Bureau of Statistics	Ministry of Planning and Empowerment		info@nbs.go.tz

Disclaimer and copyrights

Disclaimer

"The user of the data should acknowledges that, National Bureau of Statistics is the original collector of the data , the authorised distributor of the data, and the relevant funding agency bear no responsibility for use of the data or for interpretations or inferences without a written agreement from the National Bureau of Statistics"

Contacts

Name	Affiliation	Email	URL
Director General	National Bureau of Statistics	dg@nbs.go.tz

Metadata production

DDI Document ID

TZA-NBS-AGRSCS-2002-2003v01

Producers

Name	Affiliation	Role
National Bureau of Statistics	Ministry of Planning and Empowerment	Data Producer
Office of Chief Government Statistician in Zanzibar	Government of Zanzibar	Data Producer
Accelerated Data Program	PARIS21	Review of the metadata

Date of Metadata Production

2010-04-28

Metadata version

DDI Document version

Version 1.0(March 2010)

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