Survey Tabulation > Working with hierarchical data > Understanding population levels > Trip-level variables tabulated at the person level
 
Trip-level variables tabulated at the person level
The next table crosstabulates the same two trip-level variables, but this time the table is populated at the person level. This means that instead of showing the number of overseas trips that involved a particular country and purpose, each cell now shows the number of people that took trips that involved a particular country and purpose. The top left cell shows that the base for the table is 12. This is less than the base in the second table shown above (which tabulates two person-level variables at the person level) because some people did not take an overseas trip and therefore there are no records (cases) at the trip level for those people.
See also
Understanding population levels