Campaign managers know that to win an election, they must do two things: reach voters with their candidate’s information and get voters to show up at the polls. To accomplish these goals, candidates and their campaigns will often try to target those most likely to vote. Unfortunately, these voters change from election to election and sometimes from year to year. Primary and caucus voters are different from voters who vote only during presidential general elections. Some years see an increase in younger voters turning out to vote. Elections are unpredictable, and campaigns must adapt to be effective.