VARIABLE FOR "NEWCOMERS" IN THE ACS 5-YEARS ESTIMATES

Hello,

I am working on social vulnerability to floods and I use variables included in the ACS 2008-2012 estimates for census tracts as indicators for my study. Currently, I need a variable to define new residents (to measure the knowledge of the local area; familiarity with the surrounding road network and or neighborhood relationships).
I found two related variables:
1)Residence 1 year ago for the population 1 year old and over
2)Year householder moved into the housing unit

Could anybody advice me if one of these variables seem appropriate for representing newcomers in the census tract or if there is another more appropriate variable that I did not identified?

Thank you in advance!