U

Uniform Crime Reports
Standard information maintained by the U.S. Department of Justice on crime statistics as reported by participating police departments. The UCR includes the number of offenses reported and arrests made for major categories of crime.

Unit of Analysis
The class of elemental units that constitute the population and the units selected for measurement; also, the class of elemental units to which the measurements are generalized.

Univariate Analysis
An analysis of a single variable.

Unobtrusive Measures
Any method of data collection in which the subjects are not aware that they are being studied. FOR EXAMPLE, physical traces, observation, analysis of existing data, and archives.

Usability Evaluation
Assesses the degree to which a product or item can be operated by its users, the efficiency of the product/item and/or satisfaction with the product or item by the users.