​The U.S. Census Bureau engages in numerous activities to provide a positive experience for respondents and to minimize the burden associated with participating in the American Community Survey (ACS).  Based on a recommendation from the Committee on National Statistics (CNSTAT), we conducted an analysis of complaints received from respondents to understand more about the types of respondents and their perceptions of burden about the ACS.  The research consisted of two parts:  one to categorize and examine the types of complaints received and two to identify characteristics of respondents who complained.  This report presents the results of the research.