Master data management is an application framework comprising a number of different information management practices and services. And the core of most party-oriented (e.g. customer/employee/vendor, etc.) master data management systems is some mechanism for entity resolution, which fundamentally is intended to identify connections between data instances that refer to the same entity and link those data instances together.

I am being somewhat careful with my description of entity resolution for a few reasons. In a recent conversation with a marketing manager from a company developing an entity resolution product, I was repeatedly corrected to say “entity resolution” when I used the term “identity resolution” to refer to what their product did. In other situations, customers of ours who are implementing an MDM solution always refer to the same process as “identity resolution.”

Searching Wikipedia for the phrase “entity resolution” takes you to a page titled “Record Linkage.” When you go to Google and search for “entity resolution” and Wikipedia, the first result I got pointed me to a Wikipedia page titled “Identity Resolution.” After reading all the definitions, etc., though, I get the feeling there is little precision in differentiating these terms, which are basically used interchangeably, depending on how old you are, what companies you've worked for, and the recency of the articles you're reading in the technical media.

The common aspects of all the descriptions focused on examining the attribute contents of sets of records to determine with some level of confidence when subsets of the records refer to the same real-world thing. There are two practical approaches to record linkage: deterministic and probabilistic. In the deterministic approach, two records are said to match if a particular number of their corresponding attribute values match.

In the probabilistic approach, weights are assigned to each attribute and methods of scoring similarity provide scores that, when combined with the weights, are aggregated to provide an overall match score, above which a pair of records is said to match. If the score is below a lower threshold, the pair is not a match. Scores in between the thresholds require further inspection to determine whether the pair matches or not.

Clearly, any MDM system will need some kind of entity resolution technique to link records with a known identity. And unsurprisingly, most of the vendors selling MDM solutions have either built their solutions around the entity resolution capability, or have acquired companies whose main product is an entity resolution application. Here is a question, though: must entity resolution solely live in the MDM world? Or can entity resolution survive in isolation?