My comments are
1) your question about marital status better come back "not influential" for all your US survey'd people. Race, gender, marital status, etc. are all protected under US anti-discrimination laws.
2) Because I don't think your survey covered the right questions to drill down into this. What a person can do and what they say they can do are two different things. Friend-of-a-friend recommendations usually mean something more than just a resume. And a good resume usually means nothing without something to back it up. It isn't so much that the resume has little to no influence, but that I'm used to checking a resume vs. interview questions. If they say they have 8 years experience in shader programming, they damn well better be able to whip up a quick shader for me. But right off saying "i have 8 years exp" vs "i'm right out of school" makes little difference if the person can demonstrate in portfolio or phone interviews what their actual skill level is.