Shortly after the primary contests began in early January, the once-crowded Republican field was winnowed to four candidates—Mitt Romney, Rick Santorum, Newt Gingrich and Ron Paul. The sections below examine three components of the coverage of these contenders.

One element is the tone of campaign coverage for each candidate from Jan. 2 (one day before the Iowa caucus) until April 15 (five days after Santorum exited).

Another element of the study examines how much attention each contender received from the media, or the number of stories studied in which a candidate appeared in at least 25% of the story.

Another aspect of study is the frame of campaign coverage in which a candidate was a significant figure. (In the section above (“Frames of Campaign Coverage”), frame was analyzed for every story about the presidential campaign.) Sometimes, the numbers vary from the overall because more generic stories are not counted. Often, for instance, the tactical and strategic totals are higher by candidate.