Inside the Last-Ditch Hunt by Harris and Trump for Undecided Voters

Vice President Kamala Harris and former President Donald J. Trump are carrying out a virtual house-to-house hunt for the final few voters who are still up for grabs, guided by months of painstaking research about these elusive Americans.

Inside the Delaware headquarters of Ms. Harris’s campaign, analysts have spent 18 months curating a list of which television shows and podcasts voters consume in the battleground states. Her team has assigned every voter in these states a “contactability score” from 0 to 100 to determine just how hard that person will be to reach — and who is best to deliver her closing message.

The results are guiding Ms. Harris’s media and travel schedule, as well as campaign stops by brand-name supporters. For instance, the movie star Julia Roberts and the basketball great Magic Johnson earned high marks among certain voters, so they have been deployed to swing states.