F
The United Republic of Tanzania
National Bureau of Statistics Ministry of Finance Dar es Salaam February, 2012
Statistical Methods, Standards and Guidelines
i TABLE OF CONTENTS
LIST OF TABLES ............................................................................................................................... v
A LIST OF ACRONYMS ................................................................................................................. vi
PREFACE .......................................................................................................................................... ix
BACKGROUND ................................................................................................................................. x
PART I: METHODS FOR STATISTICAL PRODUCTION ....................................................... 1
A: MAIN STAGES OF STATISTICAL PRODUCTION ............................................................. 1
1.0
Introduction ..................................................................................................................... 1
1.1
Methods of Statistical Production ................................................................................... 1
1.2
Overview of Stages in Statistical Production ................................................................. 3
1.2.1
Users Demand for Statistical Data .................................................................................. 3
1.2.2
Establishing Technical Committees ............................................................................... 3
1.2.3
Formulation of Statistical Problem ................................................................................. 3
1.2.4
Information needs ........................................................................................................... 3
1.2.5
Tabulation and Analysis Plan ......................................................................................... 4
1.2.6
Formulation of Statistical Questions .............................................................................. 4
1.2.7
Data collection instruments / questionnaire design ........................................................ 4
1.2.8
Sample design ................................................................................................................. 4
1.2.9
Recruitment and training ................................................................................................ 5
1.2.10
Pilot testing .................................................................................................................... 5
1.2.11 Main fieldwork ............................................................................................................... 5
1.2.12 Data processing ............................................................................................................... 5
1.2.13 Tabulation / Analysis ...................................................................................................... 5
1.2.14 Interpretation and report writing ..................................................................................... 6
1.2.15 Dissemination and Statistical Literacy ........................................................................... 6
1.2.16 Documentation and Archiving ........................................................................................ 6
B: STANDARDS AND GUIDELINES FOR STATISTICAL PRODUCTION ........................ 7
2.0
Introduction ..................................................................................................................... 7 2.1
Survey Methodology ...................................................................................................... 7
2.1.1
Survey Planning .............................................................................................................. 7
2.1.2
Survey Designing ............................................................................................................ 9
2.1.3
Response Rates ............................................................................................................. 11
2.1.4
Focus Group Discussions (for instrument development) ............................................. 11
Statistical Methods, Standards and Guidelines
ii
2.1.5
Designing Survey Instrument(s) (Questionnaire(s)) ..................................................... 12
2.1.6
Pre-testing of Survey Instruments ................................................................................ 12
2.1.7:
Training of Trainers (TOT), Supervisors and Training of Enumerators (TOE) ........... 13
2.1.8
Pilot Testing .................................................................................................................. 14
2.2
Data Collection ............................................................................................................. 14
2.2.1
Sampling Frames .......................................................................................................... 14
2.2.2
Awareness to prospective survey respondents ........................................................... ..15
2.2.3
Methods of Data Collection .......................................................................................... 15
2.3
Data Processing ............................................................................................................ 17
2.3.1 Data Editing .................................................................................................................. 17
2.3.2
Data Coding .................................................................................................................. 18
2.3.3
Data Entry ..................................................................................................................... 19
2.3.4
Data Cleaning ............................................................................................................... 20
2.3.5
Data Protection ............................................................................................................. 20
2.3.6
Quality Evaluations ...................................................................................................... 21
2.4
Estimates and Projections ............................................................................................. 22
2.4.1
Developing Estimates and Projections ......................................................................... 22
2.5
Data Analysis ................................................................................................................ 22
2.5.1
Analysis and Report Planning ...................................................................................... 23
2.5.2
Inference and Comparisons .......................................................................................... 23
2.6
Review and Rebasing Procedures ................................................................................. 24
2.6.1
Review of Information Products ................................................................................... 24
2.7
Dissemination ............................................................................................................... 25
2.7.1
Information Release ...................................................................................................... 25
2.7.2
Documentation and Archiving ...................................................................................... 26
PART II: STANDARD CLASSIFICATIONS IN STATISTICAL PRODUCTION ............... 29
3.0
The International Standard Industrial Classification
of All Economic Activities (ISIC) ................................................................................ 29
3.1
The Classification of Individual Consumption by Purpose (COICOP)........................ 31
3.2
Tanzania Standard Classification of Occupations (TASCO) ....................................... 32
3.3
The System of National Accounts (SNA) .................................................................... 35
3.4
Government Finance Statistics (GFS) .......................................................................... 38
PART III: STATISTICAL PRODUCTS AND SERVICES ........................................................ 42
4.0
SOCIAL STATISTICS .............................................................................................. 42
Statistical Methods, Standards and Guidelines
iii 4.1
Tanzania Hiv/Aids & Malaria Indicator Survey (THIMS) ........................................... 42
4.2
Tanzania Demographic and Health Survey (TDHS) .................................................... 44
4.3
Tanzania Disability Survey ........................................................................................... 46
4.4
Population and Housing Census ................................................................................... 48
4.5
Education and Health Statistics .................................................................................... 50
4.6
Household Budget Survey (HBS) ................................................................................. 51
4.7
Consumer Price Index (CPI) ......................................................................................... 53 4.8
International Comparison Program (ICP) ..................................................................... 55
4.9
Harmonised Consumer Price Index (HCPI) ................................................................. 55
4.10.
Integrated Labour Force Survey. .................................................................................. 57
4.11
Employment and Earnings Survey. .............................................................................. 59
4.12
National Panel Survey .................................................................................................. 60
5.0
ECONOMIC STATISTICS. .............................................................................................. 67
5.1
Annual Survey of Industrial Production (ASIP). .......................................................... 67
5.2
The Production Index of Manufacturing Industry (PIMI) ............................................ 70
5.3
Industrial Census .......................................................................................................... 72
5.4
Business Survey ............................................................................................................ 74
5.5
Intergrated Business Survey (IBS) ............................................................................... 76
5.6
Tanzania Tourism Sector Survey .................................................................................. 78
5.7
Distributive Trade Survey In Tanzania ......................................................................... 80
5.8
Agriculture Sample Census .......................................................................................... 81
5.9
Gross Domestic Product (GDP).................................................................................... 88
5.9.1
Annual Gross Domestic Product .................................................................................. 88
5.9.2
Quarterly Gross Domestic Products ............................................................................. 89
5.9.3
Regional Gross Domestic Product/Regional National Accounts ................................. 91
5.9.4
National Accounts Publication ..................................................................................... 92
6.0
STATISTICAL SERVICES ............................................................................................... 93
6.1
Central Register of Establishments (CRE) ................................................................... 93 6.2
Regionaland /District Social Economic Profiles .......................................................... 95 6.3
Tanzania Socio-Economic Database (TSED) ............................................................... 95
6.5
Tanzania National Data Archive (TNADA) ................................................................. 97
6.6
NBS Website ................................................................................................................ 97
6.7
Sampling ....................................................................................................................... 98
6.8
Environment Statistics .................................................................................................. 99
Statistical Methods, Standards and Guidelines
iv 6.9
Recruitment and Training of Staff on Permanent and Temporary Terms .................. 100
6.10
NBS Library ................................................................................................................ 103
6.11
Finance ........................................................................................................................ 104
6.12
Geographical Information System- (GIS) .................................................................. 104
Statistical Methods, Standards and Guidelines
v
LIST OF TABLES
Table 1: Sample Design ..................................................................................................................... 62 Table 2: Overview of Household Questionnaire ............................................................................... 64
Statistical Methods, Standards and Guidelines
vi LIST OF ACRONYMS
AfDB
Africa Development Bank ANA
Annual National Accounts ANC
Ante Natal Care ASDP
Agriculture Sector Development Programme ASIP
Annual Survey of Industrial Production BOP
Balance of Payments CPI
Consumer Price Index CPC
Central Product Classification CRE
Central Register of Establishment CSPro
Census and Survey Processing System COICOP
Consumption of Individual Classification by Purpose DBS
Dried Blood Spots DP
Development Partner EA
Enumeration Area ESTID
Establishment‟s Identification
GDP
Gross Domestic Product GDDS
General Data Dissemination System GFS
Government Finance Statistics GIS
Geographical Information GPS
Global Positioning System GVA
Gross Value Added HBS
Household Budget Survey HBSQF
Household Budget Survey Questionnaire Form HCPI
Harmonised Consumer Price Index HIV/AIDS
Human Immunodeficiency Virus/Acquired Immuno Deficiency Syndrome IBS
Integrated Business Survey ICP
International Comparison Program ICR
Intelligent Character Recognition IEC
Information, Education and Communication ILO
International Labour Organization ILFS
Integrated Labour Force Survey ISIC
International Standard for Industrial Classification
Statistical Methods, Standards and Guidelines
vii JNIA
Julius Nyerere International Airport LGA
Local Government Authority LFS
Labour Force Survey MAB
Ministerial Advisory Board MAFS
Ministry of Agriculture and Food Security MDAs
Ministries, Departments and Agencies MDG
Millennium Development Goals
MKUKUTA
Mkakati wa Kukuza Uchumi na Kupunguza Umasikini Tanzania
MNRT
Ministry of Natural Resources and Tourism MTEF
Medium Term Expenditure Framework NBS
National Bureau of Statistics NMS
National Master Sample NPS
National Panel Survey NPISHs
Non-Profit Institutions Serving Households NACP
National AIDS Control Programme NSO
National Statistical Office NSGRP
National Strategy for Growth and Reduction of Poverty NSS
National Statistical System NSSF
National Social Security Fund OCGS
Office of Chief Government Statistician PAYE
Pay As You Earn PIMI
Production Index of Manufacturing Industry PORALG
President‟s Office – Regional Administration and Local Government PSU
Primary Sampling Unit QNA
Quarterly National Accounts RSM
Regional Statistical Manager RMSE
Roots Mean Square Error SADC
Southern Africa Development Committee
SDDS
Special Data Dissemination System SMD
Surveys and Mapping Division of Tanzania SNA
System of National Accounts SPSS
Statistical Package for Social Statistics
STIs
Sexually Transmitted Infections STPR
Short Term Price Relative
Statistical Methods, Standards and Guidelines
viii TASAF
Tanzania Social Action Fund
TASCO
Tanzania Standard Classifications of Occupations TDHS
Tanzania Demographic and Health Survey TDS
Tanzania Disability Survey TISD
Tanzania Integrated Statistical Databse TFNC
Tanzania Food and Nutrition Centre THMIS
Tanzania HIV/AIDS and Malaria Indicator Survey TNA
Training Need Analysis TNADA
Tanzania National Data Archive TOE
Training of Enumerators TOT
Training of Trainers TSED
Tanzania Socio-Economic Database TSMP
Tanzania Statistical Master Plan TUS
Time Use Survey UN
United Nations UNFPA
United Nations Fund for Population Activities UNICEF
United Nations Children Fund UTM
Universal Transverse Mercator VBA
Visual Basic for Application VETA
Vocational Education Training Authority ZCT
Zanzibar Commission for Tourism
Statistical Methods, Standards and Guidelines
ix PREFACE
This publication puts together all Methods, Standards and Guidelines that are used in the collection and compilation of official statistics in Tanzania. The objective of the publication is to harmonize and coordinate production of official statistics in the entire National Statistical System (NSS) under the umbrella of Tanzania Statistical Master Plan (TSMP).
Under the Statistics Act No. 1 of 2002, one of the main functions of the National Bureau of Statistics (NBS) is to establish statistical standards and ensure their use by all producers and users of official statistics so as to facilitate the integration and comparison of statistics produced both nationally and internationally.
Experience has shown that producers of statistics in Tanzania have been producing statistics that are sometimes conflicting. This situation has, over the years, brought difficulties for planners and decision makers to decide on which dataset to use.
In order to addres s this situation, the NBS has produced this document which provides S tatistical Methods, Standards and G uidelines to be used by all producers and users of official statistics in Tanzania. The NBS welcomes feedback, comments and suggestions that will lead t o improvement of future editions of this publication.
Dr. Albina A. Chuwa Director General.
Statistical Methods, Standards and Guidelines
x BACKGROUND
The Government of Tanzania has been implementing structural and institutional reforms which aim at improving socio-economic development. Ministries, Departments, and Agencies (MDAs), Local Government Authorities (LGAs), and other stakeholders are implementing interventions as outlined in national development frameworks in order to improve livelihood of the people. Tanzania‟s National Statistical Sys tem (NSS) comprises data producers, users, suppliers, providers, and statistical training institutions and centres in Tanzania Mainland and Tanzania Zanzibar.
The NSS has many different actors; MDAs, LGAs, and other stakeholders that collect and process data from primary providers such as villages, wards, health facilities, agricultural extension officers or schools. Much of this information is used as a basis for policy and programme formulation, planning, monitoring and evaluation analysis. The central institution within N|SS in Tanzania Mainland is the National Bureau of Statistics (NBS) while in Tanzania Zanzibar it is the Office of Chief Government Statistician (OCGS).
In order to achieve their objectives of producing statistical information and services; MDAs, LGAs and other stakeholders are required to meet agreed standards while conducting Censuses and Surveys. This is crucial for Statistics comparability and harmonization.
In line with NSS, the NBS aims to come up with methods, standards and guidelines for Tanzania Statistical Programmes to serve the interests of the MDAs, LGAs and other stakeholders. These methods, standards and guidelines outline the statistical professional principles and practices that Tanzania MDAs, LGAs and other stake holders are required to stick to the level of quality and efforts expected in all statistical activities and services. Each standard has supplementary guidelines that present recommended best practices to fulfill the goals of the standards.
These standar ds and guidelines provide a means to ensure harmonization, comparability and consistency among and within statistical activities and services conducted in Tanzania. Implementation of standards and guidelines ensures that users of Tanzania statistical infor mation, products and services are provided with details on the principles and methods employed in the planning, collection, processing, analysis, dissemination and preservation of Tanzania statistical information.
Statistical Methods, Standards and Guidelines
xi
The framework for the methods, standards and guidelines presented here includes:
Methods for statistical production
Main stages of statistical production
Standards and guidelines for statistical production
Standard classifications in statistical production
Statistical products and services
Within this framework, the re are 21 standards and their related guidelines for Tanzania Statistical
Surveys which focus on ensuring high quality statistical censuses and surveys that result in
information products satisfying MDAs, LGAs and other stakeholders for ensuring and
maximizing the harmonization, comparability and consistency of quality and integrity of statistical
information and products disseminated in Tanzania.
When conducting a Census or Survey, the MDAs, LGAs and other stakeholders should engage
knowledgeable and experienced survey personnel to effectively achieve the goals of the statistical
standards. Persons involved should have knowledge and experience in survey methodology and
dissemination as well as technological aspects of censuses and surveys.
The main goal of this document is to produce quality data that are dependent on the methods and statistical conce pts used as well as quality control procedures applied i n all stages of data production.
Statistical Methods, Standards and Guidelines
1 PART I: METHODS FOR STATISTICAL PRODUCTION
A: MAIN STAGES OF STATISTICAL PRODUCTION
1.0 Introduction Statistical production depends on various methods and stages that have an impact on the quality of data, information and indicators produced and used. Therefore, it is imperative that, this process addresses user needs and concerns in the early stages. In some cases, users demand disaggregated data and statistics at the ultimate stages whereas the initial stages did not take into account these needs. Thus, it is likewise essential that various stakeholders including subject matter specialists be involved in the statistical production process to address the user needs. As a principle, quality measures have to be instituted in all stages of data production.
1.1 Methods of Statistical Production
Administrative Records and Routine Data Systems
These are primarily established to manage operational processes - vital registration,
agriculture, education, health, water, tax collection, social security, etc.
The data generated can also be used for strategic purposes,
They are the main sources of official statistics,
Have built-in mechanisms in service delivery to collect data for measuring early
results,
They produce input, process and output indicators as well as outcome indicators to
some extent.
Censuses and Surveys
(i) Census
Collects data from every member of a given population,
It aims at providing total (100%) coverage of the population,
Conducted after every ten years in most countries,
Costly and time consuming,
They are a basis for intercensal sample surveys,
Fewer questions are asked and normally produce indicators that measure medium and
long term results (outcome and impact) of policies and programmes.