Most American voters determind their party affiliation by regional, ethnic, religious, and local factors
affiliation of the author means to what institution is related to the author
It means where the person goes to school
Possible gang affiliation.
regional
Affiliation is to be closely associated or connected to something, as in being a member.
An affiliation is an agreement to affiliate for a company.
state of affiliation or country of affiliation is the state the person has got his or her nationality
racial affiliation
affiliation
It would probably mean a party that does not participate in elections nationally, but only in some or other region when regional elections are held.
It means "where the person in question works, teaches, or goes to school."