From April to September of 2008, the ACS reduced the number of cases included in the telephone Failed Edit Follow-up (FEFU) operation. In FEFU, households who have returned a mail form but whose data failed a completeness check are called to collect the missing data. This operation is designed to improve the final quality of mail-returned questionnaires. As expected, the reduced number of FEFU cases resulted in an increase in missing data among mail respondents and thus, an increase in item allocation rates. For more information about FEFU, please refer to Chapter 7, page 7-5 of the ACS Design and Methodology report at the Design and Methodology page.