Example: Using the default values the sample size would be: SECTION FIVE: SYSTEMATIC SELECTION OF SUBUNITS For this protocol, 30 subunits should be randomly selected from among all within the survey area. Subunits should be administrative areas for which population figures are available. The ideal subunits are census enumeration areas (EAs), although villages, wards, localities or any other small administrative unit may also be used. Though EAs may require greater effort upfront than other choices of subunit, the use of EAs for survey sampling is advantageous because: they account for all households in a country in a jointly exhaustive and mutually exclusive fashion (i.e. each household in the country will fall into one and only one EA); they are among the smaller geographical units available, sometimes much smaller than villages and large towns, so they are easier to work in than larger units; they can be used in urban areas as well as rural and semi-urban areas; and, outline maps for each EA are often available, which can greatly aid in the creation of segments (Section 6). For the rest of this manual we will use the term “subunits” when referring to the first units of sample selection, be they EAs/villages/localities/etc. See the box below for a summary of this information. Enumeration Areas (EAs) Villages/Wards/Localities/Hamlets/etc. Designed to be comprehensive: jointly A household can belong to multiple villages or no exhaustive and mutually exclusive village Relatively consistent, small population size Population size can vary widely Can be used in rural, semi-urban, and urban Challenging to use in urban centers areas Maps are available, typically from the same Maps may not be available governmental office that conducts the census In order to improve the efficiency of household sampling, within each selected subunit a segment of households will be randomly selected. Sampling of households will take place only within that segment. The probability that any one subunit is selected is proportionate to the estimated number of segments it contains. The default segment size is 50 households; however, in some cases larger segments may be necessary if the expected number of households required to meet the sample size is >50 (segmentation
Example: Using the default values the sample size would be: SECTION FIVE: SYSTEMATIC SELECTION OF SUBUNITS For this protocol, 30 subunits should be randomly selected from among all within the survey area. Subunits should be administrative areas for which population figures are available. The ideal subunits are census enumeration areas (EAs), although villages, wards, localities or any other small administrative unit may also be used. Though EAs may require greater effort upfront than other choices of subunit, the use of EAs for survey sampling is advantageous because: they account for all households in a country in a jointly exhaustive and mutually exclusive fashion (i.e. each household in the country will fall into one and only one EA); they are among the smaller geographical units available, sometimes much smaller than villages and large towns, so they are easier to work in than larger units; they can be used in urban areas as well as rural and semi-urban areas; and, outline maps for each EA are often available, which can greatly aid in the creation of segments (Section 6). For the rest of this manual we will use the term “subunits” when referring to the first units of sample selection, be they EAs/villages/localities/etc. See the box below for a summary of this information. Enumeration Areas (EAs) Villages/Wards/Localities/Hamlets/etc. Designed to be comprehensive: jointly exhaustive and mutually exclusive A household can belong to multiple villages or no village Relatively consistent, small population size Population size can vary widely Can be used in rural, semi-urban, and urban areas Challenging to use in urban centers Maps are available, typically from the same governmental office that conducts the census Maps may not be available In order to improve the efficiency of household sampling, within each selected subunit a segment of households will be randomly selected. Sampling of households will take place only within that segment. The probability that any one subunit is selected is proportionate to the estimated number of segments it contains. The default segment size is 50 households; however, in some cases larger segments may be necessary if the expected number of households required to meet the sample size is >50 (segmentation
who_coverage_evaluation_survey_guidance.docx