A term signifying a relationship between two or more events or variables. Events are said to be associated when they occur more frequently together than one would expect by chance. Association does not necessarily imply a causal relationship. Statistical significance testing enables a researcher to determine the likelihood of observing the sample relationship by chance if in fact no association exists in the population that was sampled. The terms "association" and "relationship" are often used interchangeably.
AcademyHealth. Glossary of Terms Commonly Used in Healthcare, 2004 ed. Available at