Survey ID Number
BGD_2007_DHS_v01_M
Title
Demographic and Health Survey 2007
Sampling Procedure
The 2007 BDHS employs a nationally representative sample that covers the entire population residing in private dwelling units in Bangladesh. The survey used the sampling frame provided by the list of census enumeration areas (EAs) with population and household information from the 2001 Population Census. Bangladesh is divided into six administrative divisions: Barisal, Chittagong, Dhaka, Khulna, Rajshahi, and Sylthet. In turn, each division is divided into zilas, and each zila into upazilas. Rural areas in an upazila are divided into union parishads (UPs), and UPs are further divided into mouzas. Urban areas in an upazila are divided into wards, and wards are subdivided into mahallas. These divisions allow the country as a whole to be easily divided into rural and urban areas. EAs from the census were used as the Primary Sampling Units (PSUs) for the survey, because they could be easily located with correct geographical boundaries and sketch maps were available for each one. An EA, which consists of about 100 households, on average, is equivalent to a mauza in rural areas and to a mohallah in urban areas.
The survey is based on a two-stage stratified sample of households. At the first stage of sampling, 361 PSUs were selected. Figure 1.1 shows the geographical distribution of the 361 clusters visited in the 2007 BDHS. The selection of PSUs was done independently for each stratum and with probability proportional to PSU size, in terms of number of households. The distribution of the sample over different parts of the country was not proportional, because that would have allocated the two smallest divisions, Barisal and Sylhet, too small a sample for statistical precision. Because only a small proportion of Bangladesh's population lives in urban areas, urban areas also had to be over-sampled to achieve statistical precision comparable to that of rural areas. Therefore, it was necessary to divide the country into strata, with different probabilities of selection calculated for the various strata. Stratification of the sample was achieved by separating the sample into divisions and, within divisions, into urban and rural areas. The urban areas of each division were further subdivided into three strata: statistical metropolitan areas (SMAs), municipality areas, and other urban areas. In all, the sample consisted of 22 strata, because Barisal and Sylhet do not have SMAs.
The 361 PSUs selected in the first stage of sampling included 227 rural PSUs and 134 urban PSUs. A household listing operation was carried out in all selected PSUs from January to March 2007. The resulting lists of households were used as the sampling frame for the selection of households in the second stage of sampling. On average, 30 households were selected from each PSU, using an equal probability systematic sampling technique. In this way, 10,819 households were selected for the sample. However, some of the PSUs were large and contained more than 300 households. Large PSUs were segmented, and only one segment was selected for the survey, with probability proportional to segment size. Households in the selected segments were then listed prior to their selection. Thus, a 2007 BDHS sample cluster is either an EA or a segment of an EA.
The survey was designed to obtain 11,485 completed interviews with ever-married women age 10-49. According to the sample design, 4,360 interviews were allocated to urban areas and 7,125 to rural areas. All ever-married women age 10-49 in selected households were eligible respondents for the women's questionnaire. In addition, ever-married men age 15-54 in every second household were eligible to be interviewed.
Note: See detailed in APPENDIX A of the survey report.
Questionnaires
The 2007 BDHS used five questionnaires: a Household Questionnaire, a Women’s Questionnaire, a Men’s Questionnaire, a Community Questionnaire, and a Facility Questionnaire. Their contents were based on the MEASURE DHS Model Questionnaires. These model questionnaires were adapted for use in Bangladesh during a series of meetings with a Technical Task Force (TTF) that included representatives from NIPORT, Mitra and Associates, ICDDRB: Knowledge for Global Lifesaving Solutions, the Bangladesh Rural Advancement Committee (BRAC), USAID/Dhaka, and Macro International. Draft questionnaires were then circulated to other interested groups and reviewed by the BDHS Technical Review Committee. The questionnaires were developed in English and then translated and printed in Bangla.
The Household Questionnaire was used to list all the usual members of and visitors to selected households. Some basic information was collected on the characteristics of each person listed, including age, sex, education, and relationship to the head of the household. The main purpose of the Household Questionnaire was to identify women and men who were eligible for individual interviews. In addition, the questionnaire collected information about the dwelling unit, such as the source of water, type of toilet facilities, flooring and roofing materials, and ownership of various consumer goods. The Household Questionnaire was also used to record height and weight measurements of all women age 10-49 and all children below six years of age.
The Women’s Questionnaire was used to collect information from ever-married women age 10-49. Women were asked questions on the following topics:
- Background characteristics, including age, residential history, education, religion, and media exposure,
- Reproductive history,
- Knowledge and use of family planning methods,
- Antenatal, delivery, postnatal, and newborn care,
- Breastfeeding and infant feeding practices,
- Vaccinations and childhood illnesses,
- Marriage,
- Fertility preferences,
- Husband’s background and respondent’s work,
- Awareness of AIDS and other sexually transmitted diseases,
- Knowledge of tuberculosis, and
- Domestic violence.
The Men’s Questionnaire was used to collect information from ever-married men age 15-54. Men were asked questions on the following topics:
- Background characteristics, including respondent’s work,
- Marriage,
- Fertility preferences,
- Participation in reproductive health care,
- Awareness of AIDS and other sexually transmitted diseases,
- Knowledge of tuberculosis, injuries, and tobacco consumption, and
- Domestic violence
Questions on domestic violence (which were included in both the Women’s and Men’s Questionnaires) were administered to only one eligible respondent per household, whether female or male. In households with two or more eligible respondents, special procedures were followed to ensure that the selection of the woman or man was random and that these questions were administered in private.
The Community and Facility Questionnaires were administered in each selected cluster during listing. These questionnaires collected information about the existence of development organizations in the community and the availability and accessibility of health services and other facilities. This information was also used to verify information gathered in the Women’s and Men’s Questionnaires on the type of facilities respondents accessed and the health service personnel they saw.