In the previous three chapters, I have shown that campaigns behave in predictable ways based on the kinds of data available to them. Public records in some places provide clear signals of voters' partisan and racial identities; therefore, campaigns in such places focus more on mobilizing partisans and racial minorities than they otherwise would. Public records do not correlate well with voters' degree of persuadability in any place; therefore, campaigns often fail to connect with persuadable voters and prefer a strategy of mobilization. In this chapter, I provide some additional evidence to explain why public records have this strong effect on campaigns. Given the conventional wisdom that contemporary campaigns have highly advanced technology, it might be hard to believe that the availability of just a few public records predicts so much about how campaigns behave. This chapter attempts to explain further why access to public records so deeply affects campaigns.

In Chapters 2 and 3, I offered three explanations for why public records in the voter registration system ought to influence elite perceptions so much that their differential availability across jurisdictions results in different strategies pursued by campaigns. First, public records, such as party affiliation and racial registration, are highly correlated with attributes that campaigns care about. I have shown this to be the case in Chapters 5 and 6. Second, public record laws can be designed to be valuable to campaigns because politicians consider the political uses of the information when making laws about the collection of personal data. This I have shown to be the case in Chapter 3.

Third, alternative sources of information, like consumer data and social networks, are not as effective tools for perceiving voters' political attributes as public records are. I have evaluated this claim briefly in each of the previous three chapters. However, in this chapter, I add some additional clarity to this claim.