An import filter is a simple description of how to translate a CSV file, or a text file, of a particular format into an equivalent import package. The import filter is given a Donor CSV File or a Text File. The text of the filter describes how to interpret each field of each record of the file. The filter operates on one record at a time. The record is broken up into its fields and then re-assembled into one or more equivalent Match-IT records. Each input record may cause several Match-IT records, spanning several Match-IT files, to be created.

A limited field processing capability is available. This allows the translation of input fields into Match-IT fields to be dependent on the value of the fields. This conditional processing is available at the field level and the Match-IT record level. It is illustrated in the examples given later.

In summary: a filter translates a file in one format into another format.