New York State Identification and Intelligence System

NYSIIS, short for the New York State Identification and Intelligence System Phonetic Code, is a phonetic algorithm devised in 1970 as part of the New York State Identification and Intelligence System, an agency now part of the New York State Division of Criminal Justice Services. Like Soundex, it reduces a surname to a short code so that different spellings of a similar sounding name map to the same key, which helps when searching records of people whose names were written in several ways. It works by rewriting the start and end of the name by fixed rules, for example changing a leading MAC to MCC and a leading PH to FF, and then scanning the remaining letters one at a time, turning vowels into A, converting letters such as Q, Z and M to G, S and N, and dropping repeated letters. It finishes by removing a trailing S or A and shortening a trailing AY to Y. The source article reports an accuracy increase of 2.7 percent over the traditional Soundex algorithm.