I am working with the 2012 ACS 5-Year Migration estimates. Specifically, the variable of interest for me is MIGPUMA1 and I have two questions. First, why do values of MIGPUMA1 cover more than one state in the MIGPLAC1 variable if PUMAs do not cross state lines? Second, there seem to be some values of MIGPUMA1 (such as 100) that do not appear in the conversion file puma_migpuma1_pwpuma00.xls. I am confused about what those values represent.
Thank you for your help!