The sensitivity of ETK to training set size was tested by performing 50-fold cross-validation with training sets for pronunciation distance on U.S. names of sizes in {48, 96, 191, 381, 762, 1524, 3047} drawn from the 3047 equivalence classes in the 5000 U.S. names with pronunciation distance and k = 1.
despite Soundex's has many well-known limitations, including inability to handle different first letters with identical pronunciations (e.g., Soundex of "Kris" is K620, but Soundex of "Chris" is C620), truncation of long names, and bias towards English pronunciations, Soundex is still in use in many law enforcement and national security applications (dizard, 2004).