ACS PUMS users have noticed that in some cases the MV variable (when the householder moved into this house or apartment) does not appear to agree with the person's migration variables, MIG (mobility status - lived here one year ago) and MIGSP (migration recode - state or foreign country code). The MV variable is found on the housing unit files, and the migration variables are found on the person files. The apparent contradiction occurs when a householder reported that he/she lived elsewhere 12 months ago, but has an MV variable indicating that he/she had moved into the current residence years ago.

The moving back and forth is not necessarily a contradiction because some respondents have more than one dwelling and other respondents have careers or other factors that require that they live temporarily away from home. However, the internal edits for the MV variable and the migration variables are, for the most part, done independently, so it is possible that the apparent contradiction could be the result of the edits, rather than by the respondent's reported answers. Users can identify whether changes were made to these variables due to the edits (which include imputations) by looking at FMVP (When moved into this house or apartment allocation flag), FMIGP (Mobility status allocation flag), and FMIGSP (Migration state allocation flag).