Research shows little evidence that appearances can change election outcomes, and to the extent that appearances matter, it is because they lead to volunteer sign-ups and contributions. The reason to visit Wisconsin, therefore, would be to excite the base and motivate those supporters to volunteer for the campaign.
Getting out the vote relies on more than excitement, however. Translating enthusiasm into action may require establishing a “ground game.” Campaigns open field offices that serve as points of coordination for volunteer activities, where the data possessed by national campaigns is translated into walk packets and call lists for local volunteers, who in turn talk to voters and collect more data at the doors and on the phones. Offices can increase candidate vote share and turnout in an area, but perhaps more importantly, they indicate to volunteers and local activists that the national campaign cares about their area.
…Better field operations lead to better data, which improves targeting and persuasion, starting the cycle anew.
…The data [in Clinton’s 2016 campaign] may not have indicated that something was wrong, but with fewer volunteers in the field, that data was incomplete. Data and field are not competing resource centers; they should work together seamlessly, each benefiting from the insights of the other.