SanteDB Matcher

This project adds an implementation of a fuzzy matching service to the SanteDB iCDR core instance in which it is installed. It provides:

• Services for identifying duplicate records
• Services for classifying an inbound record against the iCDR's data source
• Query Filters for fuzzy searching using the HDSI query syntax

Match Process

There are two matchers that are provided in the matching project:

• DeterministicMatcher which can detect matches based on HDSI query criteria directly from the database. These matches are not scored, rather they have a probability of 0.0 or 1.0 only.
• Weighted/Scoring Matcher which uses a three stage algorithm to determine matches given a series of rules. The steps for this matcher are as follows:
  1. Blocking: In the blocking phase HDSI queries are run against the underlying database and are selected. This is done to reduce the number of records which need to be classified.
  2. Scoring: In the scoring stage, a series of transforms and measurements are done on the blocked records (from step 1), and each record is given a score. The score indicates the confidence that the record is a match.
  3. Classification: In the final stage, the weighted sum of all scores in step 2 are classified as: Match, Probable Match, or Non Match and returned to the caller

Query Filters

In SanteDB, query filters are commonly used in deterministic ways (such as =, <=, ~, etc). SanteDB 1.2 introduces the concept of extended query filters which allow consumers to indicate a transform to be performed on data prior to execution. For example, if you wanted to match a Patient's last name using Soundex instead of "LIKE" you could use:

?name.component.value=:(soundex)SMITH

Which will match SMITH, SMITHE, SMYTHE, etc.

Query filters are in the format:

property=:(extension |parameters ) operator value

Filter	Description	Example
:(date_diff|otherdate)timespan	Calculates the difference between two dates	?dateOfBirth=:(date_diff|2018-01-01)<1w Matches all patients born within one week of 2018-01-01
:(substr|start[,end])otherString	Performs a partial match on a sub-portion of the string	?identifier.value=:(substr|0,6)304-304-394 matches all patients who have an identifier starting with 304-30
:(levenshtein|otherString)distance	Calculates the levenshtein difference between the property and input	?name.component.value=:(levenshtein|Jenny)<1 matches all patients who's name is only one character different than Jenny (Jenn, Jennye but not Jennie)
:(metaphone[|specificity])otherString	Matches the field based on the metaphone code	?name.component.value=:(metaphone)Smith matches any name whose metaphone code matches SMITH
:(dmetaphone)otherString	Matches the field based on the double-metaphone code	?name.component.value=:(dmetaphone)Smith matches any name whose double metaphone code matches SMITH
:(soundex)otherString	Matches the field based on the SOUNDEX code	?name.component.value=:(soundex)Smith matches any name whose soundex code matches SMITH
:(soundslike|otherString)	Matches the field based on the currently configured phonetic algorithm handler (lets server decide the algorithm)
:(phonetic_diff|otherString[,algorithm])distance	Matches a field based on phonetic difference to another code using metaphone (default) or using soundex or dmetaphone	?name.component.value=:(phonetic_diff|SMITH)<2 Matches any name where the metaphone code is only 1 character different
:(alias|otherString)relevance	Matches records which are an alias	name.component.value=:(alias|Will)>0 will match Will, William, and Bill

Configuring The Matcher

Up to date documentation can be found on the SanteDB Wiki