The 2009 Samoa Demograthic and Health Survey (SDHS) is a national survey covering all four regions of the country. The survey was design to collect, analyze, and disseminate information on housing and household characteristic, education, maternal and child health, nutrition, fertility and family planning, gender, and knowledge and behaviour related to HIV/AIDS and sexually transmitted infections (STI).
The 2009 SDHS is the first DHS survey to be undertaken in Samoa both by the health sector and for an improved heath system. The planning and implementation of the survey was carried out jointly by the Samoa Bureau of Statistics (SBS) and the Ministry Of Health (MOH) with the technical assistance and quidance of ICF Macro. The Ministry of Women, Community and Social Development assisted by facilitating community support for the survey through villages and mayors.
Kind of Data
Sample survey data [ssd]
Version 01: This file is edited dataset, not anonymized, for internal use only.
Unit of Analysis
-Women aged 15-49,
-Men aged 15-54.
The survey covered all de jure household members (usual residents), all women aged 15-49 and men aged 15-54 years resident in the selected household.
Producers and sponsors
Authoring entity/Primary investigators
Ministry of Health
Government of Samoa
Samoa Bureau of Statistics
Government of Samoa
MEASURE DHS Program
Government of Samoa
The World Bank
The 2009 Samoa Demographic Health Survey (SDHS) survey is designed to allow reliable estimation of key demographic and health indicators such as fertility, contraceptive prevalence, and infant and child mortality.
The major domains distinguished in the tabulation of important characteristics for the eligible female population are:
- Samoa as a whole
- Each of the four regions in Samoa: (1) Apia urban area, (2) North West Upolu, (3) Rest of Upolu, and (4) Savaii
- Urban and rural areas of Samoa (each as a separate domain).
The population covered in the 2009 SDHS is the universe of all women age 15-49 in Samoa in a sample of 2,247 selected households. Every other household selected for the women's sample was also eligible for the men's sample (men age 15-54).
The primary sampling unit (PSU) for the 2009 SDHS was the cluster. As mentioned in Chapter 1, the 2009 SDHS sample was selected in two stages. The first stage involved selecting clusters from the master sample frame (the 2006 Population and Housing Census). In the second stage, all households in each selected cluster were listed. Households were then systematically selected from each cluster for participation in the survey. The design did not allow for replacement of clusters or households.
The sample was designed to include 10 percent of the households in rural areas and 12 percent of the households in urban areas. The sample was designed to permit detailed analysis of most indicators for the national level, for urban and rural areas separately, and for each of the four regions (Apia urban area, North West Upolu, the rest of Upolu, and Savaii). Overall, a total of 296 primary sampling units or clusters were selected, 104 in urban areas and 192 in rural areas. Because Samoan households do not move frequently, a fresh household listing was not deemed to be necessary. Instead, a listing from November 2006 was used. In the urban clusters, 5 households were selected per cluster, whereas in the rural clusters, 10 households were selected per cluster. The number of clusters in each of the 4 geographical regions was calculated by dividing the total allocated number of households by the sample take of 5 for Apia urban area (the number of households for urban EAs) and 10 for other regions (the number of households for rural EAs). In each region EAs were stratified by urban location first and then by rural location. Clusters were selected systematically, with probability proportional to size.
A total of 2,247 households were selected for the sample, of which 2,066 were found occupied at the time of the fieldwork. Of these, 1,947 households were successfully interviewed, yielding a household response rate of 94 percent.
In the households interviewed, a total of 3,033 eligible women were identified, of whom 2,657 were interviewed, yielding a response rate of 88 percent. Survey results indicate that 1,689 eligible men were identified in the sub-sample of households selected for the male survey and 1,307 were successfully interviewed, yielding a response rate of 77 percent.
The household and women's response rates are slightly lower in urban (92 percent and 86 percent, respectively) than in rural areas (95 percent and 88 percent, respectively), but for men, the response rate is higher in urban (81 percent) than in rural areas (76 percent).
The principal reason for non-response among eligible women and men was the failure to find them at home despite repeated visits to the households. The substantially lower response rates for men reflect the more frequent and longer absences of men from the home.
Because of the non-proportional allocation of the sample to the different economic regions, sampling weights will be required in all analysis using the DHS data to ensure the actual representativity of the sample at both the national and regional levels. The sampling weight for each household is the inverse of its overall selection probability with correction for household non-response; the individual weight is the household weight with correction for individual non-response. Sampling weights are further normalized in order to give the total number of unweighted cases equal to the total number of weighted cases at the national level, for both household weights and individual weights.
Dates of Data Collection (YYYY/MM/DD)
Time periods (YYYY/MM/DD)
Mode of data collection
Fieldwork of the survey was coordinate and supervise by Senior staff from SBS and MOH. Field staff were divided into 9 teams; 2 teams worked in the Apia Urban Area, 3 teams worked in North West of Upolu, 2 teams worked in the Rst Of Upolu and 2 teams worked in Savaii region. Each teams used 1 Van of 16 seat with a driver composed of 1 supervisors and 1 field-editor, 6 female interviewers and 2 male interviewers.
The supervisor's role is to coordinate the field data collection including management of the field teams, supplies and equipment, maps and listing, finances, coordinate with the local authorities village mayor, making arrangement, dealling the refused household, making a field spot check, transport organize for long distance household, maintained the work proccess and documents and send complete questionnaire and progress report to the main office.
The field editor's role is responsible for reviewing and checking each questionnaires at the end of each day. Checking for missing pages, skips, inconsistence in the data and also observing the interviewers and conduct a review session with the interviewer.
Type of Research Instrument
Three questionnaires were used in the SDHS: a Household Questionnaire, a Women's Questionnaire, and a Men's Questionnaire. The household and individual questionnaires were based on model survey instruments developed in the MEASURE DHS program. The model questionnaires were adapted to meet the current needs of Samoa. Each household selected for the SDHS was eligible for interview with the Household Questionnaire.
a) The Household Questionnaire was used to list all usual members of and visitors to the selected households and to collect information on the socio-economic status of the household. The first part of the Household Questionnaire collected information on the basic demographic data for Samoan households, such as age, sex, educational attainment, and relationship of each household member or visitor to the head of the household. . It was also used to identify the women and men who were eligible for the individual interview (i.e., women age 15-49 and men age 15-54). In the second part of the Household Questionnaire, there were questions on housing characteristics (e.g., the flooring material, the source of water, and the type of toilet facilities), on ownership of a variety of consumer goods, on ownership of land and farm animals, and other questions relating to the socio-economic status of the household.
b) The Women's Questionnaire was used to collect information from all women age 15-49 years and covered the following topics:
- Background characteristics (education, residential history, media exposure, etc.)
- Birth history
- Antenatal, delivery, and postnatal care
- Knowledge, attitudes, and use of family planning methods
- Fertility preferences
- Marriage, woman's work, and husband's background characteristics
- Breastfeeding and infant feeding practices
- Vaccinations and childhood illnesses
- Childhood mortality
- Knowledge of and attitudes toward AIDS and other sexually transmitted diseases
- Knowledge of and attitudes toward tuberculosis
- Other health issues
c) The Men's Questionnaire, administered to all men age 15-54 years living in every other household, collected information similar to that on the Women's Questionnaire but was shorter because it did not contain questions on reproductive history, maternal and child health, and nutrition.
After finalization of the questionnaires in English, they were translated into Samoan.
Samoa Bureau of Statistics
Government of Samoa
The processing of the Samoa Demographic and Health Survey (SDHS) results began shortly after the fieldwork started. Data editing was first done in the field by field editors and supervisors. Completed and edited questionnaires for each cluster were packed and delivered to the SDHS Centre at Moto'otua where they were entered and edited by data processing personnel. The data processing team was composed of 15 data entry operators, 1 data entry supervisor with 2 assistants, and 7 office editors working in two shifts. Data operators and supervisors went through a one-week training program conducted with the technical assistance of ICF Macro. Data were entered using CSPro, a programme specially developed for use in household based surveys and censuses. All data were entered twice (100 percent verification). The concurrent processing of the data was an advantage because the survey technical staff were able to advise field teams of problems detected during the data entry using tables generated to check various data quality parameters. As a result, specific feedback was given to the teams to improve their performances. The data entry and editing phase of the survey was completed in February 2010.
Data were entered using CSPro, a programme specially developed for use in household based surveys and censuses. All data were entered twice (100 percent verification). The concurrent processing of the data was an advantage because the survey technical staff were able to advise field teams of problems detected during the data entry using tables generated to check various data quality parameters. As a result, specific feedback was given to the teams to improve their performances. The data entry and editing phase of the survey was completed in February 2010.
Estimates of Sampling Error
Sampling errors, on the other hand, can be evaluated statistically. The sample of respondents selected in the 2009 SDHS is only one of many samples that could have been selected from the same population, using the same design and expected size. Each of these samples would yield results that differ somewhat from the results of the actual sample selected. Sampling errors are a measure of the variability between all possible samples. Although the degree of variability is not known exactly, it can be estimated from the survey results.
A sampling error is usually measured in terms of the standard error for a particular statistic (mean, percentage, etc.), which is the square root of the variance. The standard error can be used to calculate confidence intervals within which the true value for the population can reasonably be assumed to fall. For example, for any given statistic calculated from a sample survey, the value of that statistic will fall within a range of plus or minus two times the standard error of that statistic in 95 percent of all possible samples of identical size and design.
If the sample of respondents had been selected as a simple random sample, it would have been possible to use straightforward formulas for calculating sampling errors. However, the 2009 SDHS sample is the result of a multi-stage stratified design, and, consequently, it was necessary to use more complex formulas. The computer software used to calculate sampling errors for the 2009 SDHS is a Macro SAS procedure. This procedure used the Taylor linearization method of variance estimation for survey estimates that are means or proportions. The Jackknife repeated replication method is used for variance estimation of more complex statistics, such as fertility and mortality rates.
The Jackknife repeated replication method derives estimates of complex rates from each of several replications of the parent sample, and calculates standard errors for these estimates using simple formulas. Each replication considers all but one cluster in the calculation of the estimates. Pseudo-independent replications are thus created. In the 2009 JIDHS, there were 285 non-empty clusters. Hence, 930 replications were created.
In addition to the standard error, the design effect (DEFT) for each estimate is calculated, which is defined as the ratio between the standard error using the given sample design and the standard error that would result if a simple random sample had been used. A DEFT value of 1.0 indicates that the sample design is as efficient as a simple random sample, while a value greater than 1.0 indicates the increase in the sampling error due to the use of a more complex and less statistically efficient design. The relative standard error and confidence limits for the estimates are also calculated.
Sampling errors for the 2009 SDHS are calculated for selected variables considered to be of primary interest. The results are presented in an appendix to the Final Report for the country as a whole, for urban and rural areas, and for the four geographical regions. For each variable, the type of statistic (mean, proportion, or rate) and the base population are given in Table B.1 of the Final Report. Tables B.2 to B.8 present the value of the statistic (R), its standard error (SE), the number of unweighted (N) and weighted (WN) cases, the design effect (DEFT), the relative standard error (SE/R), and the 95 percent confidence limits (R±2SE) for each variable. The DEFT is considered undefined when the standard error considering simple random sample is zero (when the estimate is close to 0 or 1). In the case of the total fertility rate, the number of unweighted cases is not relevant, as there is no known unweighted value for woman-years of exposure to childbearing.
The confidence interval (e.g., as calculated for children ever born to women age 40-49) can be interpreted as follows: the overall average from the national sample is 4.559 and its standard error is 0.116. Therefore, to obtain the 95 percent confidence limits, one adds and subtracts twice the standard error to the sample estimate, i.e., 4.559±2×0.116. There is a high probability (95 percent) that the true average number of children ever born to all women aged 40 to 49 is between 4.326 and 4.791.
Non-sampling errors are the results of mistakes made in implementing data collection and data processing, such as failure to locate and interview the correct household, misunderstanding of the questions on the part of either the interviewer or the respondent, and data entry errors. Although numerous efforts were made during the implementation of the 2009 Samoa DHS (SDHS) to minimize this type of error, non-sampling errors are impossible to avoid and difficult to evaluate statistically.
Computer Programmer MOH
Computer Programmer SBS
Confidentiality of respondents is guaranteed by the Statistics Act 1971.
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 or establishment 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.
This statement does not replace a more comprehensive data agreement (see Access condition).
Licensed datasets, accessible under conditions
The dataset is not anonymized and is for internal use only. It is not yet accessible to all for statistical and research purposes until the final version is released.
"Ministry Of Health of Samoa, Bureau of Satistics of Samoa, Samoa Demograthic and Heath Survey 2009 (DHS 2009), Version 01 of the licensed dataset (January 2010), provided by the Microdata Library. https://microdata.pacificdata.org/index.php/home"
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.
Disclaimer and copyrights
This report summarizes the findings of the 2009 Samoa Demograthic nd Health Survey (SDHS) carried out by thr Ministry of Heath in collaboration with the Sasmoa Bureau of Statistics. ICF Macro provided technical assistance for the survey through a contract with the Ministry of Health. Funding for th SDHS was received from the government of Samoa, the International Development Association (IDA), the Australian Agency for International Development (AusAID) and the New Zealand Agency for International Development (NZAID).
Additional information about the survey may be obtained from the Ministry of Health, Private Bag, Apia, Samoa (Telephone: 685-68102; Fax 685-23483, email: [email protected]).
Version 01 (July2012): this is the first documentation of the Demographic and Health Survey (DHS) 2009 of Samoa.
Version 02 (July 2019): this is the review of the existing documentation. Done by Statistics for Development Division at Noumea, New Caledonia.