A BSTRACT In 2006 Polimetrix, Inc. of Palo Alto, CA. fielded the Cooperative Congressional Election Study, the largest study of Congressional elections ever fielded in the US. The project was a joint venture of 38 universities and over 100 political scientists. In this paper, we detail the design and execution of the project, with special attention to the method by which the sample was generated. We show that the estimates from the Common Content of CCES outperform conventional estimates based on RDD phone surveys. We also argue that opt-in panels, internet surveys, and cooperative ventures like CCES provide cost-effective alternatives for social scientists under certain conditions. These types of surveys can provide reductions in RMSE over conventional methods when sample matching is used to ameliorate the biases that come with sampling from an opt-in panel.

Scholars do not usually test for the duration of the effects of mass communication, but when they do, they typically find rapid decay. Persuasive impact may end almost as soon as communication ends. Why so much decay? Does mass communication produce any long-term effects? How should this decay color our understanding of the effects of mass communication? We examine these questions with data from the effects of advertising in the 2000 presidential election and 2006 sub-national elections, but argue that our model and results are broadly applicable within the field of political communication. We find that the bulk of the persuasive impact of advertising decays quickly, but that some effect in the presidential campaign endures for at least six weeks. These results, which are similar in rolling cross-section survey data and county-level data on actual presidential vote, appear to reflect a mix of memory-based processing (whose effects last only as long as short-term memory lasts) and on-line processing (whose effects are more durable). Finally, we find that immediate effects of advertising are larger in sub-national than presidential elections, but decay more quickly and more completely.2 Joseph Klapper's classic argument that exposure to mass communication rarely causes significant opinion change is no longer persuasive to many scholars (Klapper, 1960). In the laboratory and in the field, multiple studies have demonstrated fairly large and seemingly consequential effects of exposure to mass communication. 1 A handful of recent studies, however, has found that persuasion effects can be quite shortlived, decaying in a few weeks or even a few days. Best known is the Texas advertising study, which found no persistence of persuasion effects in the week following exposure to the ads (Gerber, Gimpel, Green, and Shaw, 2011). But other recent studies show similar results. For example, Mutz and Reeves (2005) found that exposure to "uncivil behavior" on TV talk shows reduced the public's level of political trust, but that trust bounced back to baseline levels in a follow-up survey.Social psychologists have grappled for decades with findings that persuasive communication often produces only short-lived effects (Cook and Flay, 1978;Petty and Wegener, 1998 raised, much less investigated, are the focus of this paper. We answer them with evidence on the effects of political advertising, but our analysis is framed in terms generally applicable within the field of mass political communication.The paper begins with the theoretical observation that, in politics as in the rest of life, citizens 1 For reviews, see Iyengar and Simon, 2000; Kinder 2003. 3 form opinions by one of two routes (Hastie and Park, 1986). In the first, memory-based evaluation, people express opinions on the basis of information available in memory when asked. In this model, the effect of persuasive messages is to create opinions that may persist only as long as the messages underlying them remain accessible in memory, which may not be long. In the...

We analyze the first large-scale, randomized experiment to measure presidential approval levels at all outcomes of a canonical international crisis-bargaining model, thereby avoiding problems of strategic selection in evaluating presidential incentives. We find support for several assumptions made in the crisis-bargaining literature, including that a concession from a foreign state leads to higher approval levels than other outcomes, that the magnitudes of audience costs are under presidential control prior to the initiation of hostilities, and that these costs can be made so large that presidents have incentive to fight wars they will not win. Thus, the credibility of democratic threats can be made extremely high. We also find, however, that partisan cues strongly condition presidential incentives. Party elites have incentives to behave according to type in Congress and contrary to type in the Oval Office, and Democratic presidents sometimes have incentives to fight wars they will not win.

Analysts of cluster-randomized field experiments have an array of estimation techniques to choose from. Using Monte Carlo simulation, we evaluate the properties of point estimates and standard errors (SEs) generated by ordinary least squares (OLS) as applied to both individual-level and cluster-level data. We also compare OLS to alternative random effects estimators, such as generalized least squares (GLS). Our simulations assess efficiency across a variety of scenarios involving varying sample sizes and numbers of clusters. Our results confirm that conventional OLS SEs are severely biased downward and that, for all estimators, gains in efficiency come mainly from increasing the number of clusters, not increasing the number of individuals within clusters. We find relatively minor differences across alternative estimation approaches, but GLS seems to enjoy a slight edge in terms of the efficiency of its point estimates and the accuracy of its SEs. We illustrate the application of alternative estimation approaches using a clustered experiment in which Rock the Vote TV advertisements were used to encourage young voters in 85 cable TV markets to vote in the 2004 presidential election.

Prior research demonstrates that many citizens are unable to perceive differences between the two major political parties. In order to investigate whether candidate behavior in campaigns contributes to this perception, we test implications about partisan constraints on campaign rhetoric drawn from the literature on parties and policy convergence. Our results suggest that candidates of different parties do not highlight the same issues or positions in their campaign advertising. We find that campaign rhetoric is strongly motivated by party even when controlling for constituency characteristics and other factors. Thus, there is convergence among candidates of the same party across districts and states and divergence between opposing candidates within districts and states. Our results are based on a detailed content analysis of more than 1,000 campaign advertisements aired by 290 candidates in 153 elections in 37 states during the 1998 midterm elections.