I see. Thank you. Considering the Census: Voter distribution and Voter Mobility are probably socio-economically determinable factors (numerically speaking) since the state legislature or whatever body is responsible for redrawing the lines gets access to the census data [per obligation of their task] that is, "age and race" ... I'd like to point out to friends from around the world that the United States census questionnaire is rather unsightly when it comes to the section entitled "race" [0].
[0] https://www.census.gov/history/pdf/2010questionnaire.pdf Page 2 question #6.