The main purpose of a HIES survey was to present high quality and representative national household data on income and expenditure in order to update Consumer Price Index (CPI), improve statistics on National Accounts and measure poverty within the country. These statistics are a requirement for evidence based policy-making in reducing poverty within the country and monitor progress in the national strategic plan "Te Kakeega 3".
The 2015-16 Household Income and Expenditure Survey (HIES) is the third HIES that was conducted by the Central Statistics Division since Tuvalu gained political independence in 1978. With great assitance from the Pacific Community (SPC) experts, the HIES was conducted over a period of 12 months in urban (Funafuti) and rural (4 outer islands) areas. From a total of 1,872 households on Tuvalu, an amount of 38 percent sample of all households in Tuvalu was selected to provide valid response.
Kind of Data
Sample survey data [ssd]
v01: Cleaned, labelled and anonymized version of the Master file.
Unit of Analysis
Household and Individual.
The scope of the 2015/2016 Household Income and Expenditure Survey (HIES) was all occupied households in Tuvalu. Households are the sampling unit, defined as a group of people (related or not) who pool their money, and cook and eat together. It is not the physical structure (dwelling) in which people live. HIES covered all persons who were considered to be usual residents of private dwellings (must have been living in Tuvalu for a period of 12-months, or have intention to live in Tuvalu for a period of 12-months in order to be included in the survey). Usual residents who are temporary away are included as well (e.g., for work or a holiday).
Producers and sponsors
Authoring entity/Primary investigators
Central Statistics Division
Ministry of Finance and Economic Development
Technical Assistance in Questionnaire design, sampling methodology, data processing and analysis
Government of Tuvalu
Mr Michael Sharp
HIES Planning, preparation, training of Fieldworkers, Processing, Analysis, Reporting and Dissemination
Mr Pierre Wong
HIES design of CSPro modules and training of Fieldworkers
Mr Toga Raikoti
Assist with the whole Processing, analysis and dissemination process
Out of the total 1,872 households (HHs) listed in 2015, a sample 706 households which is 38 percent of the the total households were succesfully interviewed for a response rate of 98%.
The 2010 (Household Income and Expenditure Survey (HIES) sample was spread over 12 months rounds - one each quarter - and the specifications of the final responding households are summarised below:
Tuvalu urban: Selected households: 259 = 217 responded;
Tuvalu rural: Selected households: 346 = 324 responded.
In 2010, 605 HHs were selected and 541 sufficiently responded. The 2010 HIES provided solid estimates for expenditure aggregates at the national level (sampling error for national expenditure estimate is 3.1%).
Similarly to the 2010 HIES, private occupied dwellings were the statistical unit for the 2015/2016 HIES. Institutions and vacant dwellings were removed from the sampling frame.
Some areas in Tuvalu are very difficult to reach due to the cost of transportation and the remoteness of some islands, which is why they are excluded from the sample selection. The following table presents the distribution of the HHs according to their location (main island or outer islands in each domain) based on the 2012 Population and Housing Census:
-Urban - Funafuti: 845 (48%);
-Rural - Nanumea: 115 (7%);
-Rural - Nanumaga: 116 (7%);
-Rural - Niutao: 123 (7%);
-Rural - Nui: 138 (8%);
-Rural - Vaitupu: 226 (13%);
-Rural - Nukufetau: 124 (%);
-Rural - Nukulaelae: 67 (%);
-Rural - Niulakita: 7 (%);
-TOTAL: 1761 (100%).
The 2012 Population and Household Census (PHC) wsa used to select the island to interview, and then in each selected island the HH listing was updated for selection. For budget and logistics reasons the islands of Nui, Nukufetau, Nukulaelae and Niukalita were excluded from the sample selection. In total 19% of the HHs were excluded from the selection but this decision should not affect the HIES outputs as those 19% show similar profile as other HHs who live in the outer islands. This exclusion will be take into consideration in the sampling weight computation in order to cover 100% of the outer island HHs.
SAMPLE SELECTION AND SAMPLE SIZE:
A simple random selection was used in each of the selected island (HHs were selected directly from the sampling frame). Based on the findings from the 2010 Tuvalu HIES, the sample in Funafuti has been increased and the one in rural remains stable. Within each rural selected atolls, the allocation of the sample size is proportional to its size (baed on the 2012 population census). The table below shows the number of HHs to survey:
Urban - Funafuti: 384;
Rural - Vaitupu: 126;
Rural - Nanumea: 63;
Rural - Niutao: 84;
Rural - Nanumaga: 63;
The expected sample size has been increased by one third (361 HHs) with the aim of pre-empting the non contacted HHs (refusals, absence….).
The 2015/2016 HIES adopted the standardized HIES methodology and survey instruments for the Pacific Islands region. This approach, developed by the Pacific Community (SPC), has resulted in proven survey forms being used for data collection. It involves collection of data over a 12-month period to account for seasonal changes in income and expenditure patterns, and to keep the field team to a smaller and more qualified group. Their implementation had the objective of producing consistent and high quality data.
Deviations from the Sample Design
For budget and logistics reasons the islands of Nui, Nukufetau, Nukulaelae and Niukalita were excluded from the sample selection. In total 19% of the HHs were excluded from the selection but this decision should not affect the HIES outputs as those 19% show similar profile as other HHs who live in the outer islands. This exclusion will be take into consideration in the sampling weight computation in order to cover 100% of the outer island HHs.
Out of the 720 households selected to be interviewed, a total of 706 household provided valid questionnaires which produces a response rate of 98%. However, a higher response rate of 98.4% is noticed on the urban island of Funafuti compared to the rural outer islands which produces 97.6 % valid questionnaires.
Urban - Funafuti: sample of 384 households => 378 questionnaires were valid (98.4%);
Rural - Outer atolls: sample of 336 households => 328 questionnaires were valid (97.6%).
The weighting process of the Tuvalu HIES is based on the probability of selection computed in the sampling design stage. The sampling weight were computed at the household level using the inverse of the probability of selection, adjusted by a factor that addressed non-response. Only 2 different weights were generated, the rural weight in the rural strata and the urban weight for Funafuti.
The variable used as weighting coefficient for the datasets is: "hh_weight". The variable is present in each of the 5 datasets.
Dates of Data Collection (YYYY/MM/DD)
Round 1 -16
Mode of data collection
Interviewing was done by teams of interviewers. Each interviewing team comprised of 2 Interviewers per Supervisor for Funafuti (urban) and 3 Interviewers per Supervisor on the Outer islands.
The Central Statistics Division (CSD) recruited and trained;
- Funafut (2 Teams)
Each Team have a Supervisor with 2 enumerators
- 4 Outer Islands (1 team each)
Each Teams have a Supervisor with 3 enumerators
- Also 3 Data Entry officers were assigned to check and enter the interviewed datas.
Team supervisors were in charge of the data entry for their team (using laptop).
Type of Research Instrument
The survey contain 4 modules and 2 Diaries (1 diary for each of the two weeks that a household was enumerated). The purpose of a Diary is to record all the daily expenses and incomes of a Household as shown by its topics below;
The Diary module contains questions such as "What did your Household buy Today (Food and Non-Food Items)?", "Payments for Services made Today", "Food, Non-Food and Services Received for Free", "Home-Produced Items Today", "Overflow Sheet for Items Bought This Week", "Overflow Sheet for Services Paid for This Week", "Overflow Sheet for Items Received for Free this Week", and an "Overflow Sheet for Home-Produced Items This Week".
The 4 modules are detailed below;
- MODULE 1 - DEMOGRAPHIC INFORMATION
The module contains individual demograhic questions on their Demographic Profiles, Labour Force status (Activities), Education status, Health status, Communication status and questions on "Household members that have left the household".
- MODULE 2 - HOUSEHOLD EXPENDITURE
The module contains household expenditure questions the housing characteristics, Housing tenure expenditures, Utilities and Communication, Land, Household goods and assets, Vehicles and accessories, Private Travel details, Household services expenditures, Cash contributions, Provisions of Financial support, Household asset insurance and taxes and questions on Personal insurance.
- MODULE 3 - INDIVIDUAL EXPENDITURE
This module contains individual expenditure questions on Education, Health, Clothing, Communication, Luxury Items, Alcohol, Kava and Tobacco, and Deprivation questions.
- MODULE 4 - HOUSEHOLD & INDIVIDUAL INCOME
This module contains household and individual questions on their income, on topics such as Wages and Salary, Agricultural and Forestry Activities, Fishing, Gathering and Hunting Activities, Livestock and Aquaculture Activities, Handicraft/Home-processed Food Activities, Income from Non-subsistence Business, Property income, transfer income & other Receipts, and Remmitances and other Cash gifts.
Depending on the information being collected, a recall period (ranging from the last 7 days to the last 12 months) is applied to various sections of the questionnaire.
The forms were completed by face-to-face interview, usually with the HH head providing most of the information, with other household (HH) members being interviewed when necessary. The interviews took place over a 2-week period such that the HH diary, which is completed by the HH on a daily basis for 2 weeks, can be monitored while the module interviews take place.
The HH diary collects information on the HH's daily expenditure on goods and services; and the harvest, capture, collection or slaughter of primary produce (fruit, vegetables and animals) by intended purpose (home consumption, sale or to give away).
The income and expenditure data from the modules and the diary are concatenated (ensuring that double counting does not occur), annualised, and extrapolated to form the income and expenditure aggregates presented herein.
Central Statistics Division
Ministry of Finance and Economic Development
The survey procedure and enumeration team structure allowed for in-round data entry, which gives the field staff the opportunity to correct the data by manual review and by using the entry system-generated error messages. This process was designed to improve data quality.
The data entry system used system-controlled entry, interactive coding and validity and consistency checks. Despite the validity and consistency checks put in place, the data still required cleaning. The cleaning was a 2-stage process, which included manual cleaning while referencing the questionnaire, whereas the second stage involved computer-assisted code verification and, in some cases, imputation.
Once the data were clean, verified and consistent, they were recoded to form a final aggregated database, consisting of:
1. Person level record - characteristics of every HH member, including activity and education profile;
2. Household level record - characteristics of the dwelling and access to services;
3. Final aggregated income - all household income streams, by category and type;
4. Final aggregated expenditure - all household expenditure items, by category and type.
An additional poverty file was also generated.
Data entry occurred on the same day or the day after the interview for the modules, while the first diary was entered in week-two and the second week diary is entered in week-three of each round. In-field data entry was conducted in order to make use of the entry validation checks and to return to the household to verify data where inconsistencies were identified.
The software used for data entry was CSPro 6.1.
Estimates of Sampling Error
RELATIVE SAMPLING ERROR (RSE):
RSEs for the aggregated income and expenditure data are presented in Appendix 3 of the "Final Report" document provided as external resource (p.76). Non-sampling errors cannot be readily measured, however it is worth noting the issues associated with non-sampling errors, including:
• both respondents and interviewers may not entirely understand the information required from the survey, which can result in misinterpretation of the question being asked and the incorrect response;
• enumerator and respondent fatigue, resulting in underreporting, especially in completion of the HH diary;
• unwillingness to fully disclose information - especially in a small-island context - such as income and expenditure on some items (e.g., alcohol, tobacco and cash donations);
• the questionnaire being in English, which could be a second language for both the interviewers and respondents, and the need to complete a written diary (noting that: three-quarters of diaries were in Tuvalun; HHs were given the opportunity to complete a Tuvalun written diary; and enumerators could mostly converse in Tuvalun when required); and
• the inability to interview HHs members living abroad but remain dependent on the HH (e.g., students living in school dormitories) or are working to support the HH (e.g., seamen living on a ship), but who have not formed another HH outside of Tuvalu.
The Statistics Act of 1978 guarrantees the issues of Confidentiality of individual/business information, rendering statistical data by the public, and measures in a case of provision of false information.
Therefore, before being granted access to the dataset, all users have to formally agree:
1. To make no copies of any files or portions of files to which s/he is granted access except those authorized by the data depositor.
2. Not to use any technique in an attempt to learn the identity of any person, establishment, or sampling unit not identified on public use data files.
3. To hold in strictest confidence the identification of any establishment or individual that may be inadvertently revealed in any documents or discussion, or analysis. Such inadvertent identification revealed in her/his analysis will be immediately brought to the attention of the data depositor.
Licensed datasets, accessible under conditions.
"Central Statistics Division of Tuvalu, Household Income and Expenditure Survey 2015-2016 (HIES 2015), Version 01 of the licensed dataset (November 2019), provided by the Microdata Library. https://microdata.pacificdata.org/index.php/home"
Disclaimer and copyrights
The Central Statistics Division of the Government of Tuvalu, bears no responsibility for any outcomes or for interpretations or inferences arising from the use of the dataset.
(c) Copyright Central Statistics Division (CSD) of the Government of Tuvalu
Version 01 (June 2019): Original documentation of the study. Done by Central Statistics Division during a South-South mission between Fiji and Tuvalu.
Version 02 (August 2019): This is the review of the existing documentation. Done by Statistics for Development Division, SPC at Noumea, New Caledonia.