Populations and Sampling FramesOutlineBasic DefinitionsTarget PopulationOut-of-scope PopulationFrame PopulationFrame Population ExampleGeographyU.S. Census GeographyEntitiesPopulation DemographicsHousehold Living Quarter DefinitionsGroup Living QuartersGroup Quarters PopulationBusiness Entity DemographicsBusiness Entity DemographicsSingle-unit Companies (SU)Multi-unit Companies (MU)Government EntitiesBusiness and Government Entity Activity ClassificationsBusiness and Government Entity Activity ClassificationsDemographic Sampling FramesCoverageRefreshing and UnduplicationDuplication and UnduplicationEconomic Sampling FramesCoverageFrame MaintenanceBasic Relations Connecting FramesGeographic RelationsBusiness Relations© John M. Abowd 2005, all rights reservedPopulations and Sampling FramesJohn M. AbowdFebruary 2005© John M. Abowd 2005, all rights reservedOutline• Basic definitions• Demographic sampling frames• Coverage and duplication• Economic sampling frames• Coverage and duplication• Basic relations connecting frames© John M. Abowd 2005, all rights reservedBasic Definitions• Target population• Out-of-scope population• Frame population• Geography• Population demographics• Business entity demographics• Government entities© John M. Abowd 2005, all rights reservedTarget Population• The “target population” is any entity satisfying the set of conditions that specify the universe• Example 1: “Human population” All people, male and female, child and adult, living in a given geographic area at a particular date.• Example 2: “Establishment population” A business or industrial unit at a single location that distributes goods or performs services on a particular date (or during a given period).© John M. Abowd 2005, all rights reservedOut-of-scope Population• An entity that is outside either the geographic region under study or other specific restrictions imposed on the target population.• Example 1: When the in-scope population is “persons age 16 or over living in households,” persons age 15 or younger and all persons living in group quarters are out of scope.• Example 2: When the in-scope population is “employer establishments,” all establishments with zero employees are out of scope.© John M. Abowd 2005, all rights reservedFrame Population• Set of target population entities that can be selected into a sample or census.• Also called a sampling frame.• Simple cases: single sampling frame is a list of all addresses to be sampled; list of all people to be sampled; list of all businesses to be sampled.• Complex sample designs use multiple frame populations to get better coverage of the target population.• Complex frame example: SIPP© John M. Abowd 2005, all rights reservedFrame Population Example• Complex frame example: SIPP (1996)• Multi-stage sample• Primary Sampling Units are geographic areas• Within PSUs:– Frame populations: Unit, Area, New Construction, Group Quarters, and Coverage Improvement. – Within each frame, clusters of housing units are selected. – In the unit and group quarters frames, the clusters contain only a single housing unit or housing unit equivalent. – In the area frame, the cluster contains four "expected" housing units– In the new construction frame, half the clusters have four expected housing units and half have eight expected units. – Statistical analysis is used to estimate the probabilities that households or individuals in the target population will be found in a particular frame– The unit frame, which is based on the most recent Census, covers about 80% of the target population in the SIPP by these estimates• http://www.sipp.census.gov/sipp/usrguide/sipp2001.pdf© John M. Abowd 2005, all rights reservedGeography• The geography of a sampling frame assigns to every latitude and longitude a fundamental geographic area• Geographic entities can be assembled uniquely by aggregating geographic areas• The basic geographic entity for the U.S. Census is the “block”© John M. Abowd 2005, all rights reservedU.S. Census Geography© John M. Abowd 2005, all rights reservedEntities• In sampling frame development every geographic location (latitude and longitude) that contains a structure (natural or man-made) capable of originating economic activity is classified as a domicile, business, or both• Entities are placed in the frame by declaring the target population to be humans beings (all domiciles), economic (all businesses and service organizations), and government• Notice that both for-profit and not-for-profit business activity are covered in the business entity scope© John M. Abowd 2005, all rights reservedPopulation Demographics• Human populations are usually categorized by current living quarters when designing demographic sampling frames• Distinguish between household living quarters and group living quarters© John M. Abowd 2005, all rights reservedHousehold Living Quarter Definitions• Housing unit: A house, an apartment, a mobile home or trailer, a group of rooms, or a single room occupied as separate living quarters, or if vacant, intended for occupancy as separate living quarters. Separate living quarters are those in which the occupants live separately from any other individuals in the building and which have direct access from outside the building or through a common hall. For vacant units, the criteria of separateness and direct access are applied to the intended occupants whenever possible.• Household: A household includes all the people who occupy a housing unit as their usual place of residence.© John M. Abowd 2005, all rights reservedGroup Living Quarters• Group quarters: all people not living in households. There are two types of group quarters: institutional (for example, correctional facilities, nursing homes, and mental hospitals) and non-institutional (for example, college dormitories, military barracks, group homes, missions, and shelters).© John M. Abowd 2005, all rights reservedGroup Quarters Population• Includes all people not living in households. • Includes those people residing in group quarters as of the date on which a particular survey was conducted. • Two general categories – the institutionalized population which includes people under formally authorized supervised care or custody in institutions at the time of enumeration (such as correctional institutions, nursing homes, and juvenile institutions) –