Assertion

In entity resolution, assertion is the ability to introduce knowledge into an Entity Identity Structure (EIS) to force resolutions or to force reference to never resolve. Match Rules can only resolve references based on the algorithms and information available. There are four (4) types of assertion runs that are made available in the OYSTER System. These are as follow:

• Reference to Reference.
• Reference to Structure.
• Structure to Structure.
• Structure Split.

Reference to Reference Assertion

Reference to Reference Assertions (RefToRef) is the most well know and used form of asserted linking. RefToRef Assertion forces multiple references to be matched and resolved into the same cluster. It is performed on references that would not match on any defined matching rule but are known to represent the same entity. An example of this could be a person who has changed addresses and also changed their name. If the user has this knowledge they can use OYSTER to force the entity reference for the original name and address to match the new name and address forcing them to resolve to the same identity. OYSTER builds and maintains an Entity Identity Structure (EIS), in the form of an xml formatted idty file. Since the identity created by this assertion run contains both the old and new name and address any further reference for the person, no matter if it is old or new, will resolve to this identity.

Reference to Structure Assertion

Reference to Structure Assertion (RefToStr) is a type of assertion created for the OYSTER system that forces multiple references to be consolidated with an existing identity structure found in the OYSTER idty file. RefToStr Assertions are used to inject references into identity structures based on knowledge about the reference. For example, a magazine company has a centralized EIS for customer and potential customer information. A subscriber changes their name address but do not want to stop receiving their magazine so they contact the magazine company to inform them of the change. The magazine company can use RefToStr Assertion to inject this new information about the subscriber into an existing identity in their knowledge base. Without RefToStr Assertion the new information for the subscriber would not have matched the identity structure using standard matching rules.

Structure to Structure Assertion

Structure to Structure Assertion (StrToStr) is a type of assertion created for the OYSTER system that forces multiple identity structures found in an existing EIS to be consolidated into a single identity structure. This is used to fix false negative matches that were produced by the OYSTER match rules. Through the use of StrToStr Assertions multiple identity structures that are later found to actually match can be forced to consolidate. These consolidations are based on previous knowledge of the references in the identity structures.

Structure Split Assertion

Structure Split Assertion (SplitStr) is a type of assertion created for the OYSTER system that forces a single identity structure found in an existing EIS to be divided into two (2) or more identity structures. This is used to fix false positive matches that were produced by the OYSTER match rules. Through the use of SpltiStr Assertion an identity structure can be forced to split and negative assertion rules are put into place in the EIS that will never allow these newly split identity structures to be merged in the future. These splits are based on previous knowledge of the references in the identity structure.

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