Server User Guides > Survey Tabulation > Working with hierarchical data > Understanding population levels
 
Understanding population levels
When you use the hierarchical view of the data, you need to understand the significance of populating tables at the various hierarchical levels. This example uses the Household sample (see The Household sample).
The structure of the levels corresponds to the structure of the loops. This means that because the trip loop is nested within the person loop, the trip level is a child of the person level. The two grids are also represented in the case data as levels, each nested within its parent level. The following diagram shows the levels structure.
Structure of levels
When you are using the hierarchical view of the data, you can define the level at which each table is to be populated. The level that you choose affects the figures that are shown in the cells of the table. When you populate a table at the top level, each case corresponds to a household and therefore the counts show numbers of households; when you populate the table at the person level, each case corresponds to a person and therefore the counts show numbers of people; when you populate a table at the trip level, each case is an overseas trip and the counts show numbers of trips, and so on.
See
Top-level variables tabulated at the top level
Person-level variables tabulated at the person level
Person-level variables tabulated at the top level
Trip-level variables tabulated at the trip level
Trip-level variables tabulated at the person level
Variables from different levels tabulated at the default level
Variables from different levels tabulated at a higher level
Tabulating variables from different “parallel” levels
Tabulating variables from higher levels at a lower level
Showing summary statistics of a numeric variable in the cell contents
Using weighting variables with hierarchical data
See also
Working with hierarchical data