A Tonga Census has been taken once in every ten years since 1956. Censuses of population were first taken in England and Scotland in March 1801, Ireland in 1811 and Australia in 1828. The first New Zealand Census was undertaken in 1851. A national population census has been taken in Tonga since 1921, although there were counts as early as 1891. After World War II, censuses in Tonga were taken regularly once in every ten years beginning in 1956, with the previous one in 1996.
The development of procedures and processes for the 2006 Census of Population and Housing made use of the lessons learned in previous censuses, and built upon recommendations for improvements.
Data consistency between censuses was an important consideration in the overall census planning. Demands for and the use of data, improvement in data accessibility and analytical tools were also considered. The usage of GIS as a mean of disseminating the census information resulted as one of the major moves forward for the 2006 Census.
The Census is the official count of population and dwellings in Tonga, providing a ‘snapshot’ of the society and its most precious resource, its people, at a point in time. The official reference period of the census was midnight, the 30th of November, 2006.
The census provides a unique source of detailed demographic, social and economic data relating the entire population at a single point in time. Census information is used for policy setting and implementation, research, planning and other decision-making. The census is often the primary source of information used for the allocation of public funding, especially in areas such as health, education and social policy. The main users of this information are the government, local authorities, education facilities (such as schools and tertiary organizations), businesses, community organizations and the public in general.
The 2006 Census was taken under the authority of Section 8 of Statistical Act Chap. 53 of 1978 which empowers the Minister of Finance to make regulations necessary to conduct the population Census. This regulation was approved by the Cabinet and cited as Census Regulation 2006. The Census regulations also indicate that the Government Statistician would be responsible for the administration and completion of the Census. In addition, the regulations enabled the Statistics Department to carry out the necessary activities required to plan, manage and implement all the necessary Census activities.
Census Planning and Management
From a planning and management perspective, the Census had two main objectives. Firstly, it was to ensure that the process of collecting, compiling, evaluating, analyzing and disseminating of demographic, economic and social data was conducted in a timely and accurate manner. The development of procedures and processes for the 2006 Census of Population and Housing made use of the lessons learned in previous censuses, and built upon recommendations for improvements.
Secondly, it was a valuable opportunity for building the capacities of employees of the Statistics Department (SD), thus resulting in enhancing the image, credibility and reputation of the Department and at the same time, strengthening its infrastructure. Emphasis was placed on having a senior staff with a wide perspective and leadership qualities. Through the use of vision, planning, coordination, delegation of responsibility and a strong team spirit, the census work was conducted in an effective and efficient manner. Staffs at all levels were encouraged to have an innovative mindset in addressing issues. Incentives for other parties to participate, both within Statistics Department Tonga Tonga 2006 Census of Population and Housing viii and outside the government, were encouraged. As a result, the wider community including donors such as AusAID, the Secretariat of the Pacific Community (SPC) in Noumea, that provided the technical assistance and the general public, were able to support the census project.
Extensive and detailed planning is needed to conduct a successful census. Areas that required planning include: enumeration procedures and fieldwork, public communication, data processing and output systems, mapping and the design of census block boundaries, dissemination procedures, content determination and questionnaire development and training. These aspects, and how they interacted with each other, played a crucial role in determining the quality of all of the census outputs. Each phase therefore required careful, methodical planning and testing. The details of such activities, and their implementation and responsibilities were assigned to 5 subcommittees composed of staff members of the SD.
Organizational Structure of the Census
A census organizational structure is designed to implement a number of interrelated activities. Each of these activities was assigned to a specific sub-committee. The census manuals provided guidelines on processes, organizational structures, controls for quality assurance and problem solving. The challenge for managers was developing a work environment that enabled census personnel to perform all these tasks with a common goal in mind. Each sub-committee was responsible for its own outputs, and specific decisions for specific situations were delegated to the lowest level possible. Problem situations beyond the scope of the sub-committee were escalated to the next higher level.
The organizational structure of the census was as follows:
a) The Steering Committee (consisting of the Head of both Government and nongovernment organizations), chaired by Secretary for Finance with the Government Statistician (GS) as secretary.
b) The Census Committee (consisted of all sub-committee leaders plus the GS, and chaired by the Assistant Government Statistician (AGS) who was the officer in charge of all management and planning of the Census 2006 operations.
c) There were five Sub-committees (each sub-committee consisted of about 5 members and were chaired by their Sub-committee leader). These committees included: Mapping, Publicity, Fieldwork, Training and Data Processing. In this way, every staff member of the SD was involved with the census operation through their participation on these committees.
The census steering committee was a high level committee that approved and endorsed the plans and activities of the census. Policy issues that needed to be addressed were submitted to the steering committee for approval prior to the census team and sub-committees designation of the activities necessary to address the tasks.
Part of the initial planning of the 2006 Census involved the establishment of a work-plan with specific time frames. This charted all activities that were to be undertaken and, their impact and dependencies on other activities. These time frames were an essential part of the overall exercise, as they provided specific guides to the progress of each area, and alerted subcommittees’ team leaders (TL) to areas where problems existed and needed to be addressed. These also provided the SD staff with a clear indication of where and how their roles impacted the overall Census process.
Monitoring of the timeframe was an essential part of the management of the Census program. Initially, weekly meetings were held which involved the GS, AGS and team leaders (TL) of the Census committee. As the Census projects progressed, the AGS and TL’s met regularly with their sub-committees to report on the progress of each area. Decisions were made on necessary actions in order to meet the designated dates. Potential risks that could negatively affect the deadlines and actions were also considered at these meetings.
For the 5 sub-committees, one of their first tasks was to verify and amend their terms of reference using the “Strengths, Weaknesses, Opportunities and Threats” (SWOT) analysis methodology, as it applied to past censuses. Each committee then prepared a work-plan and listed all activities for which that particular sub-committee was responsible. This listing included the assignment of a responsible person, together with the timeline indicating the start and end dates required to complete that particular activity. These work-plans, set up by all the 5 sub-committees, were then used by the AGS to develop a detailed operational plan for all phases of the census, the activities required to complete these phases, start and end dates, the person responsible and the dependencies, - all in a Ghant chart format. These combined work-plans were further discussed and amended in the Census team and reported to the Steering committee on regular basis as required.
Kind of Data
Census/enumeration data [cen]
Unit of Analysis
Individuals, families and private households
Version 01: Edited and cleaned data, not anonymous, for internal use.
The scope of the National Population Census includes personal information on individual characteristics, education, labor market and reproduction.
Population & Reproductive Health
The Population Census covers the whole of the Kingdom of Tonga, which includes the 5 Divisions and both Urban and Rural Areas.
All individuals in private and institutional households.
Producers and sponsors
Kingdom of Tonga
Secretariat of the Pacific Community
Government of the Kingdom of Tonga
Australian Agency for International Development
Roman Catholic Diocese of Tonga
New Zealand AID
Funding for digitisation of maps
His Majesty's Cabinet
Approval of the Population Census Proposal 2006 and the Amendments of Census Regulation 2006
Minister of Finance
Managed the implementation of the Population Census Proposal 2006 and the Amendments of Census Regulation 2006
The Census Steering Committee
Management of the Census Operation
Ministry of Lands, Survey and Natural Resources.
Resources Provided the technical assistance to update and digitise census maps
Ministry of Education
Provided over 500 primary school teachers and education officers to carry out census enumeration and supervision of census fieldwork
The National Population Census was a complete enumeration census, hence no sampling procedure was employed. A Mapping Sub-committee was formed to ensure complete coverage of the country.
The Mapping Sub-committee
Led by Mr. Winston Fainga'anuku, this committee's mandate was to ensure that good quality maps were produced. The objective was to ensure that the maps provided complete coverage of the country, were designed to accommodate a reasonable workload of one census enumerator and, that geographic identifiers could be used for dissemination purposes by the PopGIS system. Collaborations with the Ministry of Land, Survey and Natural Resources (MLSNR) began in 2004 to ensure that digitized maps for Tonga could be used for 2006 Census. Mr. Fainga'anuku was attached to the MLSNR in April 2005 to assist 'Atelea Kautoke, Samuela Mailau, Lilika and others to complete the task of digitizing the maps for Tonga. In addition, frequent visits by Mr. Scott Pontifex from the Secretariat of the Pacific Community (SPC) in Noumea, assisted to ensure that quality digitized maps were prepared. SPC also assisted by lending its digitizer which was used in this mapping project. The staff of the Statistics Department (SD) visited household sites throughout Tongatapu and the main outer islands. This exercise was to redesign the Census Block boundaries by amalgamating or splitting existing census blocks to achieve an average of 50 households per census block. Various updates within the census block maps were made. These included the names of the head of household; roads and other landmarks to ensure that current and accurate information was provided to the enumerators. Reliable maps, both for enumerators and supervisors are necessary ingredients to assist in avoiding any under or over - counting during enumeration. Included in the package of maps was: PCmap1 which indicated where the census block was located; PCmap 2 indicating details about the boundaries of the census blocks, along with the numbers of the households within the block; and a list of the head of each household on the map.
Dates of Data Collection
Data Collection Mode
Supervisors were also selected from Primary School Teachers.
Data Collection Notes
The publicity sub-committee
Led by Salote Latu, this committee’s responsibility was to ensure that the general public understood the benefits of the census, why each person was required to take part and to know how, when and what they needed to do to take part. The task of striving to obtain an understanding and the cooperation of every individual in the country through effective use of publicity was of great importance for the quality of responses required by the Census. To achieve this, the publicity sub-committee established a publicity framework. This included TV, radio programs, talkbacks, posters, newspapers articles, banners, T-shirts, IDs, and teachers’ skits.
TV and radio programs – These programs ran for two weeks during the census collection period. They were used to inform the general public about the progress and the need for cooperation on the census. During the last two weeks just prior to the enumeration, these programs were used to brief the people of Tonga about the nature of the questions that they would be asked.
Talkbacks – Talkbacks were conducted by the National radio station. They assisted the public’s perception and awareness on the complexity of Census operation, and discussed the value of their contribution and responsiveness during the enumeration. The responses from the public were very positive and the talkbacks assisted in assuring them that the sole intent of the census was the counting of people.
Spot advertisements were placed and complete versions of the questionnaire forms were published in all the newspapers in Tonga. This ensured that everyone had the opportunity to read and understand the instructions regarding the completion of the questionnaires before the enumeration began. The TV and radio stations followed up with the briefing on the correct meaning of the questions on the forms. The general aim of this activity was to minimize the response burden, by allowing the general public to have access to, and to be briefed, on the questionnaire before the actual enumeration.
Banners and posters were used to display the Census slogan, ‘Remember to be counted’, and the dates of enumeration period and census night. Similarly, T-shirts were printed with a similar content as the banners to promote awareness about the Census. Radio programs directed specifically towards the teachers were also used for publicity and were to assist in informing teachers who were involved in training and other programs.
Led by Mr. Feleti Wolfgram and Ms Pamela Mone, this committee set up a hierarchical structure with clearly defined roles and responsibilities to assist in managing the field work. Quality assurance was assured whereby the reporting system went from the enumerator to the; supervisor, district managers, Island division managers and the AGS then finally, then to the GS and Steering committee as required.
The selection of Enumerators/Supervisors was made from primary school teachers. Where possible, the teacher who resided in a particular census block was the enumerator of that block. This was an additional asset due to the local knowledge of the teacher about the census block boundaries and its residents.
The enumeration procedures were publicly announced on the first day of the enumeration, the 28th of November, noting that the responsible enumerator should visit all households. This first visit was to update the household listings. The enumerator and the head of the household were to arrange a mutually convenient time for enumeration to take place during the enumeration period, from the 28th of November to the 4th of December. This was to ensure that the enumerator will minimize repeated visits to the households and that the households would be prepared and available to spend enough time to answer the questions. In addition, if a household was not visited on the 28th of November, then one of the household members was asked to contact the SD so that it could ensure that the responsible enumerator followed up. On the other hand, if a household was visited more than once within this period, then, the household should contact the SD for clarification and to prevent over counting by having a household enumerated twice.
Both members of the fieldwork and training sub-committees ensured through quality checks the careful process of printing, procurement, distribution and the collection of forms. In addition, the training materials (enumerators and supervisor’s manuals, questionnaire manuals, and field visits records) were managed in the same way. Several decisions regarding printing were made early in the planning process, including confirmation of the timetable for the delivery of forms to the printers, the completion date of printing, the number of questionnaires to be printed, the numbers and addresses of field locations, and the start and end dates of field enumeration. Printed materials were also needed for various tests that were carried out as well as for the training of field staff. The organization of transportation especially to the outer islands was made on time and according to schedule. Communications were assisted by good weather conditions.
The training sub-committee
Led by Ms. Siosi’ana Fisi’inaua, this committee managed the preparation of various manuals. These included the enumerators’, supervisors’ and questionnaire manuals. These activities were conducted commencing with the draft questionnaire form and amendments were made as the questionnaires were updated.
The structure and implementation of the training program were managed mainly by the training and fieldwork sub-committees. This was to ensure that the training program in addressing a particular area of work, included adequate reference to other related areas since there was substantial interaction among the different areas of work.
The three training sessions were conducted throughout the Kingdom following the training of trainers. These sessions were divided into three-half day sessions in each training center, with approximately 25 – 30 enumerators and supervisors in each session. During the last day of each training session, teachers were given forms to test enumerating two households and then correct the forms using group discussions the next day. After the 3rd day, the training team moved to the other centers and then returned came back within 3-4 weeks for the distribution of materials.
This was also used to recap any queries especially with the questionnaire forms that may have arisen during the interim period. Also, telephone lines were established in the head office for teachers to call for clarification on any problem encountered during this process.
Training sessions for the outer islands were conducted close to the enumeration period, when training officers moved from the main islands with all necessary materials for training and enumerations. This was to minimize traveling expenses, since officers from SD spent about 8 – 10 weeks in the islands carrying out training and enumeration activities.
Primary School Teachers
Ministry of Education
Ministry of Education
To meet the users’ needs, data quality requirements and the ability of the public to provide information, the design and wording of the Census forms needed careful development and testing. The Census questionnaire for 2006 consisted of two forms; A Household Form PC1 and, a Personal Form PC2.
The census team reviewed the Pacific Islands model questionnaire together with the 1996 census questionnaires, as the first step in formulating the 2006 Census questionnaire form. These two forms were distributed to all stakeholders, including Government and non-government organizations and members of the steering committee, to assist them in identifying their policy issues that could be addressed by questions on these two forms. They were then asked to bring forward their unaddressed policy issues to the SD or the steering committee meetings for consideration.
It was made clear that the content of the questionnaire form was to be discussed and finalized within the steering committee with stakeholders, whereas the questionnaire design was to be the role of the SD in collaboration with SPC. After many discussions regarding the questionnaire content in both the steering committee and census committee, the AGS then brought this proposed content to a Pacific census planning meeting in Nadi, where questionnaire design was to be addressed. At the meeting, representatives from ABS, Stats NZ, UNSD, SPC and other Pacific countries discussed the questionnaire content and design. The AGS brought back the outcome of the meetings to SD and they then, together with SPC, produced draft questionnaires for Tonga. This draft was adapted to address Tonga’s national needs for census information. As was mentioned, this draft questionnaire form was a product of the Pacific model questionnaire, Tonga’s 1996 questionnaire form (comparability), policy issues from stakeholders and the outcome of the Pacific Islands census planning workshop in Nadi. After some minor amendments, the steering committee approved the content of the questionnaire form and then asked the SD and SPC to determine any design details.
The SD staff conducted 3 informal pilot tests of the questionnaire form. At the same time, the SPC was advising on various aspects of the form to incorporate slight changes so that questions were clearer and thus permit improved data capture. Some changes resulted from the different perceptions that the respondents had regarding the interpretation of the questions that SD and SPC had not identified before the pilot test. As a result of the pilot tests, the questionnaire form was significantly improved and a number of potential problems were resolved prior to the actual enumeration. During this time, feedback from the data processing perspective also contributed to an improved questionnaire form. The final and formal pilot test was done with a sample selection of the census blocks and was also used to estimate the amount of time each household would require for enumeration.
Data Processing Sub-committee
Led by Mr. Sione F. Lolohea, this committee undertook the task of validating the responses where necessary and converting them into data for statistical analysis and dissemination. It was necessary that the various phases of the data processing were planned and implemented to ensure that the questionnaire was designed and formatted to permit accurate and complete data capture. Field checks and record forms were used for checking, verification and recording during the enumeration. Quality assurance procedures, such as those described above, were implemented to ensure that the data was recorded accurately so as to minimize any inconsistency. This was especially relevant in the interactions between Supervisors and Enumerators during the field operation. It was also used to produce a quick preliminary total population count, which was published before Christmas of 2006.
The designing of data entry screens, data dictionary, edit specifications, batch edits, tabulation plans and all related data processing systems were implemented comprehensively and according to schedule. During these processes, the SPC data processing technical advisor, Ms Leilua Taulealo worked closely with Mr. Lolohea and his team, in providing technical assistance where necessary. In addition, coding manuals were devised to code the relevant questions as part of the data processing exercise.
Once the data processing systems were ready, the coding of information began in January 2007 followed by the data entry. During these activities, recontact with households with problem forms was conducted either by phone or personal contact to ensure that the responses on the questionnaires were as accurate and reliable as possible. Following the data entry, editing and tabulations the analysis was conducted by Mr. Andreas Demmke of the SPC in collaboration with Mr. Sione Lolohea. The 2006 Census report is composed of two volumes; the Aministrative and the Basic Tables and the Analytical reports.
Estimates of Sampling Error
Not applicable to a full enumeration census.
Post – Enumeration Survey (PES)
For the post-enumeration survey (PES) 5 census blocks were selected: 2 blocks from the urban areas (Kolofo’ou-Pahu, Kolomotu’a - Longolongo), and 3 blocks from the rural areas (Vani, Nukunuku, and Neiafu). The PES count in these areas recorded (slightly) less people than counted in the actual census enumeration. While the discrepancy in population numbers of the PES compared to the census enumeration could be explained by either an undercount of the PES, or an over count (double count) of the census population, the most likely explanation is the high mobility (emigration) of the Tongan population during period of the census and PES count.
Use of the dataset must be acknowledged using a citation which would include:
- the Identification of the Primary Investigator
- the title of the survey (including country, acronym and year of implementation)
- the survey reference number
- the source and date of download
Statistics Department, Tonga. Census of Population and Housing 2006. Ref. TON_2006_PHC_v01_M. Dataset downloaded form [source] on [date].
Tonga Department of Statistics
Disclaimer and copyrights
The user of the data acknowledges that the Statistics Department Tonga and the Secretariat of the Pacific Community bear no responsibility for use of the data or for interpretations or inferences based upon such uses.
DDI Document ID
Statistics Department Tonga (SDT)
Documentation of the Census
Accelerated Data Program
International Household Survey Network
Editing for the IHSN Survey Catalog
Date of Metadata Production
DDI Document version
Version 01 (August 2012). This is the first Documentation of Tonga Census of Population and Housing 2006. This is the edited version of the documentation produced during the July 2012 workshop in Nadi, Fiji.