Horse race journalism is a term used to describe instances of political journalism

Political journalism

Political journalism is a broad branch of journalism that includes coverage of all aspects of politics and political science, although the term usually refers specifically to coverage of civil governments and political power....

 of elections  that resemble coverage of horse races because of focus on polling data, public perception instead of candidate policy, and almost exclusive reporting on candidate differences rather than similarities. "For journalists, the horse-race metaphor provides a framework for analysis. A horse is judged not by its own absolute speed or skill, but rather by its comparison to the speed of other horses, and especially by its wins and losses."