The United Republic of Tanzania
SECOND EDITION
National Bureau of Statistics Ministry of Finance and Planning Dar es Salaam June, 2017
Statistical Methods, Standards and Guidelines i
TABLE OF CONTENTS
LIST OF TABLES ......................................................................................................................... IV
LIST OF ACRONYMS ................................................................................................................... V
PREFACE ................................................................................................................................... VIII
BACKGROUND ............................................................................................................................ IX
PART I:
STATISTICAL PRODUCTION ............................................................................... 1
A: METHODS AND STAGES OF STATISTICAL PRODUCTION ..................................... 1
1.0
Introduction .............................................................................................................................. 1
1.1
Methods of Statistical Production ............................................................................................ 1
1.2
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 .................................................................................................. 6
1.2.14 Interpretation and Report Writing ............................................................................ 6
1.2.15 Dissemination and Statistical Literacy ..................................................................... 6
1.2.16 Documentation and Archiving .................................................................................. 7
B: STANDARDS AND GUIDELINES FOR STATISTICAL PRODUCTION ..................... 8
2.0
Introduction .............................................................................................................................. 8
2.1
Survey Methodology ................................................................................................................ 8
2.1.1 Survey Planning .......................................................................................................... 8
2.1.2 Survey Designing ...................................................................................................... 10
2.1.3 Response Rates ......................................................................................................... 12
2.1.4 Focus Group Discussions (for instrument development) ......................................... 12
2.1.5 Designing Survey Instrument(s) (Questionnaire(s)) ................................................. 13
2.1.6 Pre-testing of Survey Instruments ............................................................................ 13
2.1.7 Training of Trainers (TOT), Supervisors and Training of Enumerators (TOE) ........ 14
2.1.8 Pilot Testing .............................................................................................................. 15
2.2
Data Collection ...................................................................................................................... 15
2.2.1 Sampling Frames ...................................................................................................... 15
2.2.2 Awareness to Prospective Survey Respondents ....................................................... 16
2.2.3 Methods of Data Collection ...................................................................................... 16
2.3
Data Processing ...................................................................................................................... 19
Statistical Methods, Standards and Guidelines ii
2.3.1 Data Editing .............................................................................................................. 19
2.3.2 Data Coding .............................................................................................................. 19
2.3.3 Data Entry ................................................................................................................. 20
2.3.4 Data Cleaning – Range, Consistency Checks and Validation .................................. 21
2.3.5 Data Protection ......................................................................................................... 21
2.3.6 Quality Evaluations .................................................................................................. 22
2.4
Estimates and Projections ...................................................................................................... 23
2.4.1 Developing Estimates and Projections ..................................................................... 23
2.5
Data Analysis ......................................................................................................................... 24
2.5.1 Analysis and Report Planning ................................................................................... 24
2.5.2 Inference and Comparisons ...................................................................................... 24
2.6
Review and Rebasing Procedures .......................................................................................... 25
2.6.1 Review of Information Products ............................................................................... 25
2.7
Dissemination ........................................................................................................................ 26
2.7.1 Information Release .................................................................................................. 26
2.7.2 Documentation and Archiving .................................................................................. 27
PART II:
STANDARD CLASSIFICATIONS IN STATISTICAL PRODUCTION ........... 30
3.0
The International Standard Industrial Classification Of All Economic Activities (ISIC) ..... 30
3.1
The Classification Of Individual Consumption By Purpose (COICOP) ............................... 32
3.2
Tanzania Standard Classification Of Occupations (TASCO) ................................................ 33
3.3
International Classification Activities For Time Use Statistics (ICATUS) ........................... 37
3.4
Harmonized Commodity Description And Coding System (HS) .......................................... 38
3.5
Standard International Trade Classification (SITC) .............................................................. 38
3.6
Central Product Classification (CPC) .................................................................................... 39
3.7
The System Of National Accounts (SNA) ............................................................................. 40
3.8
Classification Of The Functions Of Government (COFOG) ................................................. 43
3.9
Government Finance Statistics (GFS) ................................................................................... 44
PART III: STATISTICAL PRODUCTS AND SERVICES ....................................................... 48
4.0
SOCIAL STATISTICS ........................................................................................................ 48
4.1
Tanzania HIV Impact Survey (THIS) .................................................................................... 48
4.2
Tanzania Demographic And Health Survey And Malaria Indicator Survey (TDHS-MIS) ... 51
4.3
Tanzania Service Provision Assessment (TSPA) .................................................................. 54
4.4
Tanzania Disability Survey .................................................................................................... 56
4.5
Population and Housing Census (PHC) ................................................................................. 59
4.6
Education and Health Statistics ............................................................................................. 62
4.7
Household Budget Survey (HBS) .......................................................................................... 63
4.8
Consumer Price Index (CPI) .................................................................................................. 66
4.9
International Comparison Program (ICP) .............................................................................. 68
4.10
Harmonised Consumer Price Index (HCPI) .......................................................................... 69
4.11 Integrated Labour Force Survey. ........................................................................................... 71
4.12 Employment and Earnings Survey ........................................................................................ 74
4.13 National Panel Survey ........................................................................................................... 77
5.0
ECONOMIC STATISTICS ................................................................................................ 82
Statistical Methods, Standards and Guidelines iii
5.1
Annual Survey Of Industrial Production (ASIP) ................................................................... 82
5.2
The Index of Industrial Production (IIP) ............................................................................... 85
5.3
Census Of Industrial Production ............................................................................................ 87
5.4
Producer Price Index (PPI) .................................................................................................... 89
5.5
Construction Industry Survey (CIS) ...................................................................................... 90
5.6
Tanzania Tourism Sector Survey ........................................................................................... 93
5.7
Export and Import Price Indices (XMPI) .............................................................................. 97
5.8
Distributive Trade Survey in Tanzania .................................................................................. 99
5.9
Agriculture Sample Census ................................................................................................. 100
5.10 Large Scale Farms Survey ................................................................................................... 106
5.11 Agriculture Routine Data Collection System ...................................................................... 107
5.12 Annual Agriculture Sample Survey ..................................................................................... 108
5.13 Annual Gross Domestic Product .......................................................................................... 111
5.14 Quarterly Gross Domestic Products .................................................................................... 113
5.15
Regional Gross Domestic Product/Regional National Accounts ......................................... 113
5.16
National Accounts Publication ............................................................................................ 114
6.0
STATISTICAL SERVICES .............................................................................................. 117
6.1
Statistical Business Register (SBR) ..................................................................................... 117
6.2
Regional and District Social Economic Profiles .................................................................. 120
6.3
Tanzania Socio-Economic Database (TSED) ...................................................................... 121
6.4
Census Info .......................................................................................................................... 122
6.5
Tanzania National Data Archive (TNADA) ........................................................................ 123
6.6
Countrystat ........................................................................................................................... 124
6.7
Enhanced General Data Dissemination System (E-GDDS) ................................................ 124
6.8
The NBS Website ................................................................................................................ 125
6.9
Sampling .............................................................................................................................. 126
6.10 Environment Statistics ......................................................................................................... 127
6.11
Tax Statistics ........................................................................................................................ 128
6.12 The NBSLibrary .................................................................................................................. 129
6.13 Finance ................................................................................................................................. 130
6.14 Geographical Information System (GIS) ............................................................................. 131
Statistical Methods, Standards and Guidelines iv
LIST OF TABLES Table 1: Sample Size (number of households) .............................. Error! Bookmark not defined.
Statistical Methods, Standards and Guidelines v
LIST OF ACRONYMS AfDB
African 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 SBR
Statistical Business Register
CSPro
Census and Survey Processing System COICOP
Classification of Individual Consumption by Purpose DBS
Dried Blood Spots DDC
Dewel Decimal Classification DP
Development Partner e-GDDS
Enhanced General Data Dissemination System EA
Enumeration Area ESTID
Establishment’s Identification
FDES
Framework for Development of Environment Statistics FYDP
Five-Year Development Plan GDP
Gross Domestic Product GDDS
General Data Dissemination System GFS
Government Finance Statistics GFSM
Government Finance Statistics Manual 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 Immune Deficiency Syndrome IBS
Integrated Business Survey ICP
International Comparison Program ICR
Intelligent Character Recognition
Statistical Methods, Standards and Guidelines vi
IEC
Information, Education and Communication ILO
International Labour Organization ILFS
Integrated Labour Force Survey IMF
International Monetary Fund ISIC
International Standard for Industrial Classification 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 NSDP
National Summary Data Page 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 REPOA
Research on Poverty Alleviation RSM
Regional Statistical Manager RMSE
Roots Mean Square Error
Statistical Methods, Standards and Guidelines vii
SADC
Southern Africa Development Community
SDDS
Spatial Data Dissemination System SDG
Sustainable Development Goals SMD
Surveys and Mapping Division of Tanzania SNA
System of National Accounts SPSS
Statistical Package for Social Scientists
STIs
Sexually Transmitted Infections STPR
Short Term Price Relative TCIRS
Table of Common Indicators Required for Surveillance 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 Database 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 UNESCO
United Nations Educational, Scientific and Cultural Organisation UNFPA
United Nations Fund for Population Activities UNDP
United Nations Development Program 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 viii
PREFACE This is a comprehensive publication that puts together all Methods, Standards and Guidelines that are used in the collection and compilation of official statistics in Tanzania Mainland. The main objective of the publication is to harmonize and coordinate production of official statistics in the entire National Statistical System (NSS). The publication is a product of collaborative commitments from a number of stakeholders of statistics within our National Statistical System.
According to Statistics Act No. 9 of 2015, among the main functions of the National Bureau of Statistics (NBS) is to establish statistical standards for the collection, analysis and publication of official statistics to ensure uniformity in quality, adequacy of coverage and reliability of Statistical information.
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 statistics to rely on to plan or formulate policies for the development of the country and its people.
In order to rectify this situation, the NBS has been producing a number of guidelines and frameworks and updating them regularly for the purpose of making sure producers of official statistics within the country’s NSS are applying standard principals and standards to produce statistics that meet the expected standards for use locally and at the same time to meet the need for international comparisons. On the other hand, the guidelines and frameworks produced aim at enabling the consumers of statistics to objectively determine whether the statistics put forth meet the required quality dimensions before they decide to use them. As earlier stated, this and other guiding documents produced by the National Bureau of Statistics are updated regularly; hence the NBS welcomes constructive feedback, comments and suggestions that will be input into future editions of this publication.
Dr. Albina A. Chuwa Director General.
Statistical Methods, Standards and Guidelines ix
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 System (NSS) comprises data producers, users, suppliers, providers,
statistical training institutions and research centres in Tanzania Mainland and Tanzania Zanzibar.
The NSS has different actors that includes; MDAs, LGAs, and other stakeholders who collect and process data from primary providers such as individuals, households, communities, institutions, and establishments. Much of this information is used as a basis for policy formulation, planning, programme designing, monitoring and evaluating a number programs that implemented in different sectors of the country’s economy. The National Bureau of Statistics (NBS) in Tanzania Mainland and Office of Chief Government Statistician (OCGS) in Tanzania Zanzibar are the central institutions within NSS mandated to coordinate the production process of official statistics in the country.
In order for the MDAs, LGAs and other stakeholders to achieve the desired objectives in producing statistical information and providing services, they must meet agreed standards when conducting Censuses, Surveys, and handling administrative data within their institutions so as to ensure uniformity in quality, adequacy of coverage and reliability of Statistical information.
To serve the need for uniformity in quality, adequacy of coverage and reliability in statistics production process in the country, the NBS as the coordinator, has the role developing and disseminating methods, standards and guidelines, and other frameworks that are regularly updated to meet the desired goal. These methods, standards and guidelines outline the statistical professional principles and practices that MDAs, LGAs and other stakeholders are required to follow step-by-step in the statistical production process. Each standard has supplementary guidelines that present recommended best practices to fulfill the goals of the standards.
These standards and guidelines provide a means to guarantee 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 information, products and services are provided with details on the principles and methods employed in