The 2022 Tanzania Demographic and Health Survey and Malaria Indicator Survey

The sample design for the 2022 TDHS-MIS was carried out in two stages and was intended to provide
estimates for the entire country, for urban and rural areas in Tanzania Mainland, and for Zanzibar. For
specific indicators such as contraceptive use, the sample design allows for estimation of indicators for each
of the 31 regions-26 regions in Tanzania Mainland and 5 regions in Zanzibar.
The sampling frame excluded institutional populations, such as persons in hospitals, hotels, barracks,
camps, hostels, and prisons. The 2022 TDHS-MIS followed a stratified two-stage sample design. The first
stage involved selection of sampling points (clusters) consisting of enumeration areas (EAs) delineated for
the 2012 Tanzania Population and Housing Census (2012 PHC). The EAs were selected with a probability
proportional to their size within each sampling stratum. A total of 629 clusters were selected. Among the
629 EAs, 211 were from urban areas and 418 were from rural areas.
In the second stage, 26 households were selected systematically from each cluster, for a total anticipated
sample size of 16,354 households for the 2022 TDHS-MIS. A household listing operation was carried out
in all the selected EAs before the main survey. During the household listing operation, field staff visited
each of the selected EAs to draw location maps and detailed sketch maps and to list all residential
households found in each EA with addresses and the names of the heads of the households. The resulting
list of households served as a sampling frame for the selection of households in the second stage. During
the listing operation, field teams collected global positioning system (GPS) data-latitude, longitude, and
altitude readings-to produce one GPS point per EA. To estimate geographic differentials for certain
demographic indicators, Tanzania was divided into nine geographic zones. Although these zones are not
official administrative areas, this classification system is also used by the Reproductive and Child Health
Section of the Ministry of Health. Grouping of regions into zones allows for larger denominators and
smaller sampling errors for indicators at the zonal level. The zones are as follows:
Tanzania Mainland:

• Western zone: Tabora, Kigoma
• Northern zone: Kilimanjaro, Tanga, Arusha
• Central zone: Dodoma, Singida, Manyara
• Southern Highlands zone: Iringa, Njombe, Ruvuma
• Southern zone: Lindi, Mtwara
• Southwest Highlands zone: Mbeya, Rukwa, Katavi, Songwe
• Lake zone: Kagera, Mwanza, Geita, Mara, Simiyu, Shinyanga
• Eastern zone: Dar es Salaam, Pwani, Morogoro
  Introduction and Survey Methodology • 3
  Zanzibar:
• Zanzibar zone: Kaskazini Unguja, Kusini Unguja, Mjini Magharibi, Kaskazini Pemba, Kusini Pemba
  All women age 15-49 who were either usual residents or visitors in the household on the night before the
  survey interview were included in the 2022 TDHS-MIS and were eligible to be interviewed. In a
  subsample of half of all households selected for the survey, all men age 15-49 were eligible to be
  interviewed if they were either usual residents or visitors in the household on the night before the survey
  interview. In this subsample, children age 0-59 months, women age 15-49, and men age 15-49 were
  eligible for height and weight measurement. Children age 6-59 months were also eligible for anaemia and
  malaria testing using rapid tests. Women were eligible for anaemia testing and were asked to provide a
  urine sample for laboratory testing to detect the presence of iodine. In this subsample of half of
  households, anaemia and malaria testing were conducted using capillary blood.
  A subsample of approximately 20% of all households was selected for the micronutrient component.
  Within those households, all interviewed women age 15-49 and children age 6-59 months were eligible
  for venous blood collection. In 40% of the households selected for micronutrient testing, a dose of vitamin
  A was administered, and an additional blood sample was collected approximately 4 hours later for relative
  dose response testing. Questions on food fortification were asked, and samples of salt, wheat flour, maize
  flour, and cooking oil were collected from the household. Blood specimens and food samples were
  collected, processed, and sent to TFNC for storage and analysis. Drops of the venous blood collected from
  women and children in the field were tested on-the-spot for anaemia and malaria. Haematocrit was
  measured in venous blood collected from women, and all blood samples were processed on the same day
  they were collected to prepare them for frozen storage until the start of laboratory testing. A range of
  micronutrient laboratory analyses was carried out by TFNC. The results for all tests conducted in the 20%
  of households included in the micronutrient component will be published in a separate report. Results of
  the anaemia testing for children and women in this micronutrient subsample using venous blood are
  published in this report and will be included in the separate micronutrient report as well.