This report is one in a series that compares  data from the American Community Survey  (ACS) with data from the Annual Social and  Economic Supplement (ASEC) to the Current  Population Survey (CPS). The report focuses on  comparisons of national and state distributions  of veteran status and period of military serv ice between the 2007 ACS and the 2007 ASEC.  It  suggests possible explanations for  those differences that are both  statistically and substantively  different.