There is an error in the way the imputation flag for citizenship was set. This error led to an understatement of the number of people for whom citizenship was imputed. People who had their place of birth (i.e., country of birth) imputed as the United States, Puerto Rico, Guam, the U.S. Virgin Islands, or the Northern Marianas should also have had their citizenship flag set to imputed. However, this did not occur. This error will be corrected in future releases of the ACS data files.