Unit of Observation
When social science methodology is used to collect data, the entity
which is observed or about which information is collected is the unit of
observation.
The unit of observation is the same as the unit of
analysis when the generalizations being made from a statistical analysis
are attributed to the unit of observation (i.e., the objects about which
data were collected and organized for statistical analysis).
While the units of observation and analysis are often the
same, the wealth of secondary data sources creates opportunities to conduct
analyses with data from multiple units of observation. This is probably most
recognizable in GIS research.
Example: A major national study uses a form that collects
information about each person in a dwelling and information about the
housing structure. Therefore, this study collects data for two units of
observation: persons and housing structures. From these
data, different units of analysis may be constructed: Household
could be examined as a unit of analysis by combining data from people
living in the same dwelling. Family could be treated as the unit of
analysis by combining data from all members in a dwelling sharing a
familial relationship. This expresses how the unit of analysis
can be constructed from units of observation consisting of some type
of relationship constructed by time, space or social properties.
Frequencies