This census is the 8th population census of Tonga since 1956, and the 6th census conducted by the Statistics Department.
The 2016 Census was taken under the authority of revised Statistics Act No. 7 of 2015. A review of the Statistical Act (1978) Chapter 53, 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 2011. The Census regulations also indicate that the Government Statistician is 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.
Censuses of population were first taken in England and Scotland in March 1801, Ireland in 1811 and Australia in 1828. The first New Zealand 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 up to 2006. In 2011 Census of Population and Housing was the first time to conduct Census in a five-yearly interval, and 2016 is the second one.
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 census date was midnight, the 30th of November 2016. It is the official count of population, dwellings and households in Tonga and it provides a ‘snapshot’ of the country at one specific point in time: 30th of November 2016. Since 1956 until 2006, Census has been taken once in every ten years.
The Population and Housing Census (PHC) provides a unique source of detailed demographic, social and economic data relating the entire population and its most precious resource of its people. This information is used for policy making and planning, monitoring and evaluation, research and other decision-making.
The PHC is often the primary source of information such as used for 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 population census 2016 was the second population census by 5 years interval after the previous census in 2011. This was requested by the Electoral Boundary Commission (EBC) according to its Act 2010, Section 21(1) which states that:
(1) To facilitate the second determination of boundaries under this Act, the Minister responsible for the administration of the Statistics Act shall cause a general population census to be carried out before the next General Election.
(2) The Government Statistician shall certify and provide to the Commission such Information, calculations and projections that the Commission may enable it to perform its functions under this Act.
The Statistics Department first sought the Minister of Finance’s approval to conduct this census. Once, this approval was received, the census proposal was prepared. The proposal was submitted to the Minister of Finance for endorsement to the Cabinet with the recommendation “That the Statistics Department conduct the Tonga Population Census and Housing on 30th November 2016(census date), and Ministry of Finance and National Planning assist with obtaining of necessary funding for the census be approved.”
Kind of Data
Census/enumeration data [cen]
Unit of Analysis
Version 01: edited data of the de-identified dataset.
Functioning, Social Behaviour & Illness
Education, Languages And Literacy
Economic Activities Last Week
Fertility And Mortality
Communications And Internet
Agriculture And Fishing
GPS + Photo
Producers and sponsors
Tonga Statistics Department
Government of Tonga
Government of Tonga
Tonga Health Promotion Foundation
The United Nations International Children's Emergency Fund (UNICEF)
Donation of equipments
Director of Education
Donation of equipments
Dates of Data Collection
Data Collection Mode
Data Collection Notes
The most distinct feature about the 2016 Population and Housing Census was using new technology –tablets using CAPI for data collection. Tonga had been the first country in the Pacific to use tablets for a Population Census.
Statistics Department had planned to take into account the great advantages that associated this methodology. Tablets were able to contribute to cutting down budget cost, and avoid long period taken for data processing phase and not the least enable monitoring of fieldwork simultaneously. Later advantages include institutionalizing across ministries these equipment. There were 600 tablets all together where 100 was donated by UNICEF and 500 purchased by Tonga Government. Out of those 600, 55 Huawei tablets were purchased first and used during the Census Listing and 545 Samsung tablets were later purchased prior fieldwork.
Computer-Assisted Personal Interview (CAPI)
To improve data quality in data collection, The Tonga National Statistics Office (TNSO), in collaboration with the Statistics for Development Division (SDD) of the Pacific Community (SPC), embarked on a new venture to use CAPI technology in their data collection for the 2016 Population and Housing Census.
One the biggest challenge in National Statistics Office is the collection of good quality data – data which is reliable and timely and the TNSO was one of the first countries in the Pacific region to use the technology in their Population Census.
Through the recommendation and technical assistance of SDD, the World Bank Survey Solution application was used for the data collection which involves the use of 600 Android Tablets to be used by Interviewers for the data collections, and Supervisors and Headquarters in their monitoring and evaluation of the data collection.
The Survey Solution software was identified as one of the best tool for data collection due to its capabilities of monitor data collection and data quality. Every completed questionnaire is sent to the respective supervisors to check and either rejects the questionnaire back to the interviewers if there are any errors/inconsistencies or approves the questionnaire if he/she is satisfied with the completed questionnaire. Rejected questionnaires are then verified and corrected by the interviewers with the respective household while they are still in the field, which ensures data quality is collected from the field by the interviewers.
The use of the GPS in the tablets, together with the capturing the photo of each visited house ensures the interviewers are visiting their correct Enumeration Area (EA) as well as proof of visiting the house. With the GPS points, Supervisors and Headquarters staffs were able to plot these GPS points on the map and identify those interviewers who may have enumerated in a wrong EA or had overlapped to other EAs assigned to another interviewer. In summary, improved data quality is attained through correcting survey processes during the field operation.
One of the biggest advantages of using Survey Solutions was the capability to allow for data collection to continue without internet access and this gives more flexibility for interviewers to undertake their work in areas without internet access and only synchronizes the completed questionnaires once they have access to the internet later.
Digicel was the main service provider for the technology which includes tablets for the Pilot, 3G SIM Cards, DATA and other technical assistance in terms of APN (Access Point Network) and daily reports of data usage by the tablet users. There was only one island where the other service provider was used as Digicel coverage was not so efficient.
The Questionnaire was designed using the Survey Solution Questionnaire Designer Tool, which has the facilities to include validations, consistency and logic checks as well as well-designed skip patterns to assist the interviewers in collecting good quality data.
The use of CAPI involves massive planning, preparation, training and testing and this resulted in a number of trainings being undertaken by the staff of the TNSO with SDD in Questionnaire Design and the full process of using Survey Solution Tools.
A listing was undertaken first, which was a good introduction to the technology as it was only for a few questions and the staff, together with about 50 project staff, were able to learn the different processes involved as well as get acquainted to the use of tablets for data collection.
Following the listing, was the Pilot testing and then followed by the Training of Trainers (TOT) of about 100 persons who went through intensive training for two full weeks in the full processes of using tablets. Most of these training sessions were mainly on practical work where they were trained to being an Interviewer, a Supervisor as well as being a Headquarter so they fully understand the different processes and responsibilities involved with these three components of Survey Solutions. After completion of the training, they were then dispatched to their respective areas to train their interviewers before the actual enumeration starts.
The hierarchical structure of the tablet system was of clear defined levels and one which ensured that all was cooperating also enabled the SD office to monitor the work of the enumerators and supervisors during the period. Issues that aroused were dealt with according to the hierarchy. The highest level of the hierarchy was the Headquarter which were the officer who did the final approval of the questionnaire form. Second level of the hierarchy is the Supervisors which was the senior officers and teachers who were responsible for the first hand detail checking of the questionnaire forms send to them by the enumerators. The bottom rank was the enumerators who were responsible for enumerating and sending the forms to the supervisors for checking and from there to the headquarters.
The enumerators were divided into groups in according to the location of the block they were to enumerate. Each group consist an average of 6 enumerators who were to report to 1 supervisor. Each supervisor was to report to headquarter and headquarters was responsible for an average of 2 supervisors and respective teams. Every enumerator was assigned 1 census block to enumerate in time using the tablets that was distributed to them during the training period.
The selection of Enumerators and Supervisors was made from primary school teachers. Where possible, the teacher who resided or close to 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 16th of December 2016. This was to ensure that the enumerator minimized 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, 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.
A direct toll-free telephone line was established in the head office for teachers to call for clarification on any problem encountered during this process. A CUG (Closed User Group) was set for all tablets to enable the enumerators and supervisors to communicate freely with regards to fieldwork queries.
The census team worked cooperatively to distribute the tablets and other materials such as questionnaire manual, bags, umbrella and t-shirts during the training period for practicing and to use when the enumeration period began. At the end of the enumeration period the supervisors were advised to collect all tablets and accessories of their respective groups and hand in to the SD office to census team who were checking and collecting them.
Tonga Statistics Department
Ministry of Finance
The questionnaire is made of 9 modules in total (from A to I) and is in English with the Tongan translation below each question. The questionnaire was designed with Survey Solutions.
The questionnaire is available in the external resources section.
Data editing and cleaning was collaborated with the assistance of SPC.
Data processing was composed of different phases which include; error checking and correction through CAPI system, data cleaning and editing, and tabulation. The most distinct advantage of using CAPI (Computer-Assisted Personal Interviewing) with tablets was shown in the data processing phases. The systematic structure of the operations of the tablet system enabled the data processing to be done simultaneously with the fieldwork during the enumeration period.
Application software called Survey Solutions (privileged by World Bank) was installed into the tablets to enable the enumerators to view, receive and send the questionnaire forms. Prior to that, the questionnaire was designed and uploaded to the system. Validation sequences and quality checks were implemented into the electronic questionnaire to ensure that quality and accurate data was achieved.
For the post-enumeration survey (PES), 7 census blocks were selected: 4 blocks from seven districts in Tongatapu, 1 block from each Ha’apai and Vava’u respectively and 1 from ‘Eua. The PES count in some areas recorded slightly less people. In other areas, more people were counted than the actual census enumeration. The discrepancy in population numbers could be explained by the high mobility of the Tongan population during the period of the census and the PES count.
"National Statistics Office of Tonga, Population and Housing Census 2016 (PHC 2016), version 01 of the licensed dataset (July 2017), provided by the Pacific Microdata Library. http://pdl.spc.int/index.php/home"
The user of the data acknowledges that the original collector of the data, the authorized distributor of the data, and the relevant funding agency bear no responsibility for use of the data or for interpretations or inferences based upon such uses.
DDI Document ID
Statistics for Development Division
Documentation of the study
Date of Metadata Production
DDI Document version
Version 01 (December 2018): First attempt at documenting the 2016 Tongan Census.