title: Semantic equivalence
text: # Semantic equivalence
  
  In computer metadata, semantic equivalence is a declaration that two data elements from different vocabularies contain data that has similar meaning. There are three types of semantic equivalence statements:
  
  * Class or concept equivalence. A statement that two high level concepts have similar or equivalent meaning.
  * Property or attribute equivalence. A statement that two properties, descriptors or attributes of classes have similar meaning.
  * Instance equivalence. A statement that two instances of data are the same or refer to the same instance.
  
  ## Example
  
  Assume that there are two organizations, each having a separate data dictionary. The first organization has a data element entry:
  
  and a second organization has a data dictionary with a data element with the following entry:
  
  these two data elements can be considered to have the same meaning and can be marked as semantically equivalent.
  
  