The SLK is derived by joining the ‘letters of name’ (2nd, 3rd and 5th letters of the family name, and 2nd and 3rd letters of the first given name), ‘date of birth’, and ‘sex’ to create a 14 character identifier. There are also some instances where the SLK information may be unknown, and substitute characters are used instead.
The format of the key is XXXXXDDMMYYYYN where:
• XXXXX is the 2nd, 3rd and 5th letters of the family name and the 2nd and
3rd letters of the first name. For example: John Smith becomes ‘MIHOH’
• DDMMYYYY is the Patient’s Date of Birth
• N is the Patient’s Sex, where 1 = Male and 2 = Female
Non Alphabetic Characters such as spaces and hyphens (“-“) are ignored. If a name is too short to extract a character, a 2 is substituted for this character. If a patient is missing a family name or has a single name only, 999 is substituted for the family name component
Usage
The SLK is used for deterministic linkage. The linkage key is designed to make it possible to count number of patients and services they received, without counting the same patient more than once. For ePPOC this will allow determination of whether patients have multiple episodes at one or more PMSs, enabling a more accurate picture of patient numbers and patterns of assistance.