9.2.3 Truncated String Comparison  'FieldComparatorTruncateString'

This field comparison function allows the comparison of strings that can be truncated at a certain position using the argument max_string_length. Only the first max_string_length characters in both strings are compared. Similar to the exact string comparison function, this field comparator compares the two fields (or field lists) given to it as strings and returns the agreement weight if the truncated strings are the same and the disagreement weight if they differ.

If a frequency table is given for this field comparator, the agreement weight will be calculated using the frequency of the value in the input fields that are compared, as described in Section 9.2.1.