Unit of Observation

A unit of observation is an object about which information is collected. Researchers base conclusions on information that is collected and analyzed, so using defined units of observation in a survey or other study helps to clarify the reasonable conclusions that can be drawn from the information collected.

An example of a unit of observation is an individual person. Other examples include a family or a neighborhood.

A survey or other type of study can involve many different levels of units of observation. For example, the U.S. Census 2000 used a hierarchical arrangement to describe the units of observation about which it collected information. These units range from “United States” to “region” to “census block.”

Some researchers distinguish between the terms unit of observation and unit of analysis. For example, a unit of observation might be an individual person, but a unit of analysis might relate to the neighborhood in which the individual lives, based on data collected about individuals in the neighborhood. Clear articulations of units of observation through use of specific definitions lend clarity to survey and study efforts.

Focusing on the unit of observation throughout the course of a study—from inception to conclusions to dissemination of results—helps researchers later present an organized explanation of the phenomenon and helps keep the explanation relevant to the data collected.