A Specific Approach

Is there a way that we can do it without our questions only being interested in a certain demographic of people? I am not sure that it is best to limit the people who are relevant to our research. Is there a way that we could look the reasons why people vote for a specific party? If we focus on where they get their political information from (ie: media outlets) we could look at whether the amount of increased media coverage has caused an increase in political knowledge/interest.