The class of elemental units that constitute the population and the units selected for measurement, or the class of elemental units to which measurements are generalized. In an evaluation of an organizational capacity development effort, the unit of analysis might correspond to the individual, group, project team, department, network, partnership, or other organizational unit.

The object under study. This could be people, schools, cities, etc.

The basic observable entity being analyzed by a study and for which data are collected in the form of variables . Although a unit of analysis is sometimes referred to as the case or "observation," these are not always synonymous. For instance, in public opinion polls, the unit of analysis is usually a single person and the answers to the survey questions by one person constitute a "case." In a census, however, a "case" could be considered the household because all the data for one household is collected on one survey instrument; the household "case" may contain different variables for the different units of analysis: a physical housing structure, a family within the structure, a person within the family. Contrast with Unit of observation.

The actual object being investigated (e.g., persons, classrooms, organizations, nations).