Linkage variables used to generate tokens	Token 1 Patient last name Patient first initial of first name Patient gender Patient DOB Token 2 Patient last name (Soundex) Patient first name (Soundex) Patient gender Patient DOB
Cleaning and pre-processing of linkage variables	De-identification software applies a series of validators and cleaners before a token is generated
	Validators First name and last name should be more than 1 character Gender: Requires that the field is MF, mf, or female or male (case insensitive) If any field fails a validation test, the token is not created
	Cleaners Removes all non-alphabetic characters. Alphabetic characters include A–Z and a–z Removes all non-numeric characters. Numeric characters include 0–9 Removes all characters that are not a number (0–9) or letter (A–Z + a–z) Capitalizes all alphabetic characters (a–z → A–Z)
DOB: date of birth.