The reason politicians and media focus on polls is that polling provides a vital link between voters and candidates. Surveys give a representative sample of citizens a voice to communicate with their elected officials and candidates seeking office. And, of course, polls create news.
Many polls focus on the “horse-race” or the trial heats – who’s ahead, who’s trailing, who’s surging, who’s sinking. But election polls really provide a snap-shot in time of what is often a fast-moving target, even at the last minute, as in 2016. But polling does much more.