This chapter provides an overview of convenience sampling in political science experimental research. We first define convenience sampling and track its use in political science research. Next, we focus on the use of three sample types: undergraduate convenience samples, crowdsourced convenience samples, and other types such as social media and non-student convenience sample samples. We review empirical research on the potential issues with each convenience sample type, along with best practices that can be used to address those issues. Overall, we conclude that while there are justified concerns that scholars should be aware of when using convenience samples, much of the empirical research suggests that they provide valid results for experimental treatment effects that reliably replicate across more representative probability samples.

By the end of this chapter the reader should reach one conclusion: people dislike partisans. One might even go as far as to say that people hate partisans. When the two parties debate and disagree, people start to view partisans in a negative way. They do not want to work with partisans, they do not want to live with partisans, and they think partisans are generally unattractive, incompetent, and unlikable.

This may not seem surprising given the results in Chapter 3. After all, we show that there is a prevailing belief that being independent is more socially beneficial than being a partisan and, more importantly, that people shift away from partisan labels to make a better impression on others. But the level of dislike for partisans that we demonstrate in this chapter should be surprising for a number of reasons.

First, the extent to which people dislike partisans is surprising given the importance that political scientists often place on political parties. Political parties are considered the backbone of the American democratic process, the sorting mechanism by which voters’ preferences are translated into governmental outcomes (Aldrich 1995; Schattschneider 1942). In addition, partisans are often more likely to be politically active (Verba et al. 1995), and political participation is something that academics consider a good thing (Holbrook and Krosnick 2010). Partisan debate is widely considered an important component of any healthy democracy.

Second, a preference for one option need not translate to a dislike of the other alternative. A person, for example, may prefer Coca-Cola but have little ill will toward Pepsi and may even be willing to drink Pepsi if it were the only option available. Similarly, a person may believe that the label “independent” is a more socially beneficial signal but might also view partisanship as a moderately desirable (or at least relatively neutral) label. But, as we will demonstrate in this chapter, this is not the case.

One pundit who does not share the media's fascination with – and some might say glorification of – independents is New York Times columnist and noted curmudgeon Stanley Fish. In a 2008 column entitled “Against Independent Voters,” Fish produced a 1,131-word battle cry in support of the American political party. “What do independent voters do?” Fish asked, “Well, most of all, they talk about the virtue of being an independent voter.” Fish indicted the independent for providing a lot of sanctimonious talk with no meaningful action. Far from working to promote a better political outcome, according to Fish, independents merely obsess over the ways in which they are above the fray. “I can't stand the partisan atmosphere that has infected our politics,” Fish's fictitious independent laments.

Fish's argument, facetious as it may be, does raise an important question: what do independents do? Political scientists have long suggested that, at the very least, independents cast votes, largely for the same party, election after election – that is, independents who vote Democratic usually do so consistently and independents who vote Republican can be counted on to continue to vote for Republicans. It is this pattern that leads many researchers to conclude that independents are largely politically inconsequential (see, for example, Keith et al. 1992). We suggest that this focus on the ballot box not only is narrow but also has limited our understanding of why people hide their partisan identities and what undercover partisans mean for American politics.

In this chapter, we challenge existing evaluations of how undercover partisans participate in politics by shifting the question: What don't independents do? We already know that, for one, these people do not immediately tell researchers which party they support. More importantly, however, they may also be hesitant to share this information with their family members, friends, coworkers, and neighbors. This latter point is distinctly more consequential because politics is inherently social.

Midway through the twentieth century, Paul Lazarsfeld and his colleagues at Columbia University highlighted a crucial factor in how individuals form preferences during a political campaign: “the two-step flow of communication” (Lazarsfeld et al. 1948), by which political information travels from elites to voters and then outward to their friends and family.

“Whoever wins independent voters in Ohio, wins Ohio,” Mitt Romney's political director told Fox News with forty-eight hours to go until Election Day 2012. Meanwhile in the Democratic camp, the party's Hamilton County, Ohio chairman stressed to the Financial Times, “We need a good, solid turnout among the independent voters.” During the 2012 presidential campaign, the American media published nearly 2,000 articles addressing the thoughts, ideas, and feelings of independent voters like Kentucky resident Jennifer Cummins, quoted at the beginning of this chapter. Pundits and political operatives proclaimed that persuading independents like Cummins to pick one party over the other would be the key to electoral victory.

The pundits and political operatives who believe that independents can be persuaded are wrong.

Political scientists have known for nearly half a century that Cummins, along with the vast majority of independents, have most likely already chosen a candidate long before Election Day.

“Voters are not ‘declaring independence’ from political parties.…In fact, the American electorate is much more partisan than in the recent past,” writes political science professor and blogger John Sides. The very same people who avoid partisan labels, scholars find time and again, are independent in name only. When asked, the majority of independents will admit that they lean toward one of the two major parties, and these “leaners” appear suspiciously partisan in practice (Hajnal and Lee 2010, p. 46). They vote consistently for one party as opposed to another (Keith et al. 1992; Magleby et al. 2011), they express attitudinal support for one party over another (Keith et al. 1992; Magleby et al. 2011), and their policy preferences and affective predispositions line up consistently with just one of the two parties (Iyengar and Westwood 2014; Magleby et al. 2011). For these reasons, political scientists have dismissed independents – like Jennifer Cummins – as politically inconsequential.

But the political scientists who believe independents are politically inconsequential are also wrong.

In this book we argue that both media and political scientists fundamentally misunderstand independent voters. At best, media view independents as objective observers of American politics.

Consider these two facts: (1) nearly 40 percent of Americans identify as political independents; (2) 58 percent of Americans believe that America needs a third party. The conditions seem perfect for a third party to emerge onto the American political scene. At the very least, one might expect that Democrats and Republicans should embrace bipartisanship in hopes of appealing to so many disaffected Americans.

Yet in reality, the reverse is happening. Alternatives to the Republican and Democratic parties have declined dramatically over the past century (Tamas and Hindman 2014), as has voter support for third and minor parties (Hirano and Snyder 2007). Meanwhile, Democratic and Republican candidates are increasingly ideologically extreme (Großer and Palfrey 2014) and the American public often appears increasingly partisan, especially in their affect toward members of the opposing party (Iyengar et al. 2012; Mason 2014).

How is it possible that an electorate in which nearly a plurality of people claim they are independent exists in this political climate? One of the greatest divides in American politics may well be the chasm between what we say and what we do.

Throughout this book, we have shown the degree to which negative perceptions of partisanship influence the way ordinary Americans relate to politics. From self-identifying as independent to withdrawing from political conversation, eschewing outwardly partisan forms of political participation, and avoiding partisan coworkers and neighbors, many Americans are going undercover and deliberately avoiding partisanship. Throughout these chapters, however, we have not addressed the elephant in the room. How is it that Americans are both anti-partisan and politically polarized?

In this chapter, we examine whether the people who reject partisanship are distinct from those who are polarized. Although undercover partisans may not actually be “independent” in the political sense of the word, perhaps they are so ashamed of parties that they have begun to seek compromise and hold their representatives accountable to bipartisan values. We explore what undercover partisans want from parties in two ways. First, we take people at their own word and we simply ask people who call themselves “independent” to tell us what they want from politics and from their representatives.

Everyone wants to make a good impression. As a result, we tend to modify our behaviors – for example, by pretending to like something we actually do not like at all just for the sake of impressing the people around us. The desire to make a good impression is so pervasive that even we, the authors of this book, are not immune to it. We began this chapter with a quote from the classic novel Jane Eyre, written by Charlotte Brontë. Many people respect Brontë's work, and, deep down, we felt that opening our second chapter with a quote from Jane Eyre would lead readers to form a better impression of us. Secretly, though, the passage we really wanted to open with is from an episode of the television show Friends. Rachel – one of the characters on the show – claims that her favorite movie is Dangerous Liaisons because she does not want to admit that her favorite movie is actually Weekend at Bernie's. Much like Rachel's concern about the negative judgments associated with loving Weekend at Bernie's, we too worried that opening with a reference to Friends would leave a negative impression of us (even though we do believe that Friends makes for a better opener to this chapter than Brontë).

The problem for American political parties, as we will discuss in this chapter, is that the parties want to be respectable, like Dangerous Liaisons, but they are really more like Weekend at Bernie's – something that one might secretly support but would rather not associate with publicly. The presence of independents, we argue, goes hand-in-hand with the perception that being a partisan is not something to be proud of. As a result, people are reluctant to behave in any way that might lead others to identify them as supporters of political parties.

In this chapter, we make our way through a series of political puzzles. Previous scholarship has concluded that independents are merely undercover partisans, but we move beyond this conclusion. We consider what it is about American politics that motivates partisans not only to report that they are independent but also to avoid forms of political participation that may be perceived as partisan.