Are Credit Scores based solely on Credit History or is your income also a determining factor?

What I'm asking is: If you are poor and have an excellant payment history, never late on a credit card payment or house payment, etc., would you have as high of a credit score as someone who is 'well to do'? I'm not asking if a poor person could get a million dollar loan, I'm sure income is a factor there; I'm asking if their credit score would be the same, based on a perfect credit history. Please help me with an answer. Thank you.