A Specific Approach

I think your ten year time series format focusing on eligible voters will be effective. In terms of the broad consensus issue: voter turnout/political participation as a result of media coverage, I think based on the questions suggested that this should be divided into three central issues. The first being a definition of what media coverage in fact encompasses (Is it just TV/Print/Radio/Major News Sites, or should we include new information outlets like blogs, facebook, and twitter?). Second, the relationship you mentioned between growth in media coverage and the effect this has on voter turnout over time. Finally, whether or not there is a partisan element to coverage, and whether this has the effect of redirecting voters from one party to another, or swinging undecideds. We can then decide whether we want to focus this media analysis locally, or take a broader approach focusing on Canada or the US, and figure out the questions specifically in the Question Wording section.