The Statistical Analysis Of Roll‐Call Data: A Cautionary Tale

Roll‐call voting and congressional procedures are two of the most heavily studied aspects of the U.S. Congress. To date, little work has focused on the effect of procedures on the composition of the roll‐call record. This article takes a step in this direction by demonstrating the effect of chamber rules and institutional constraints on House and Senate roll‐call data, as well as on the inferences that scholars have drawn from the roll‐call record. More specifically, I focus on recent efforts to measure party effects and ideological alignments, and I demonstrate that the composition of the roll‐call record can affect these measures.     

Comparing Cosponsorship and Roll‐Call Ideal Points

We use bill cosponsorship and roll‐call vote data to compare legislators' revealed preferences in the U.S. House of Representatives and the Argentine Chamber of Deputies. We estimate ideal points from bill cosponsorship data using principal‐component analysis on an agreement matrix that included information on all bills introduced in the U.S. House (1973–2000) and Argentine Chamber (1983–2002). The ideal‐point estimates of legislators' revealed preferences based on cosponsorship data strongly correlate with similar estimates derived from roll‐call vote data. Also, cosponsorship activity in the U.S. House has lower dimensionality than cosponsorship has in the Argentine Chamber. We explain this lower discrimination as a function of individual‐ and district‐level factors in both countries.     

Last Post for “The Greatest Generation”: The Policy Implications of the Decline of Military Experience in the U.S. Congress

This paper characterizes the behavioral and policy implications of the decline in the number of military veterans in the U.S. Congress, from more than 70% of legislators in the early 1970s to less than 30% in the contemporary House and Senate. Many scholars argue that military service shapes information and beliefs, and that this decline has had negative effects on defense policy. The analysis tests these arguments using voting data from the House and Senate in the 1990s and the House in the 1970s, showing that the impact of veteran status on votes is generally small and has a relatively minor effect on legislative outcomes.     

Override propensity in the US congress: veto challenge and override vote by the two chambers

In contrast to the study of the US presidential veto, the study of the congressional override of vetoes has been scarce. This study examines the influences of partisanship in Congress, presidential popularity, presidential legislative assertiveness and the chamber in which a bill originated. By using the logit model, the article examines the models of House veto challenge, Senate veto challenge, House vote for override and Senate vote for override. The study shows substantial influences of the presidential party's margin, the cameral origin of a bill and the president's legislative assertiveness on the veto challenges by the two chambers. However, none of the variables are significant in the models of override vote. This may suggest fragmented decision-making in Congress after it decides to challenge a veto.     

The politics of abortion in the House of Representatives in 1976

The discussion in the U. S. Congress preceeding the passage of the 1976 Hyde Amendment, prohibiting the use of Medicaid funds for abortions, was described and the results of a multivariate analysis of the factors influencing the votes on the amendment in the House of Representatives were presented. Between June 24-August 10, 1976 there were 3 roll call votes on the amendment in the House of Representatives and during this period support for the amendment increased from 54%-69%. Multiple classification analysis was used to analyze the relative influence of 11 independent variables on the voting behavior of the representatives. The 11 variables included 1) the age, educational level, sex, and religious affliation of the representative; 2) the representative's party affliation, degree of constituent support, and previous voting record on liberal issues; and 3) the average income, racial composition, geographical location, and the % of urban residents in the representative's district. The factor which served as the best indicator of the representative's vote on the amendment was the representative's previous voting record on liberal issues. Those with more liberal voting records tended to vote against the amendment and those with more conservative voting records tended to vote for the amendment. The 2nd best predictor of amendment votes was the religious affliation of the representative. Catholic representatives, compared to Protestant and Jewish representatives, were more likely to support the amendment. Geographical location of the representative's district was a moderate indicator of the representative's vote on the amendment. Representatives from the south were more likely to support the amendment. The degree of constituent support for the representative in his own district was also a moderate indicator of the representatives vote on the amendment. The 11 factors together accounted for 1/3 of the votes.     

Different Houses: The Distribution of Earmarks in the U.S. House and Senate

Nearly all studies of pork‐barrel politics in the U.S. Congress focus on the House, biasing our conception of how politics influences federal spending and skewing our attention toward factors that are active in the House. This article highlights differences between the Senate and House in how pork is allocated. We identify four important differences between the House and Senate, generate hypotheses regarding how each difference should influence the distribution of pork projects, and test these hypotheses using data from earmarks in the Appropriations bills passed by the two chambers for fiscal year 2008. The results support three of our four hypotheses, suggesting that senators are driven by different motivations than House members. These results imply that theoretical accounts of pork‐barrel spending need to account for these interchamber differences. Our findings also highlight how studies of legislative behavior, more generally, need to account for important differences in legislative structure and organization.     

The Effects of Uncontested Elections on Legislator Performance

Political competition lies at the core of representative democracy. Yet, uncompetitive elections and uncontested races are widespread in the United States, particularly at the state level. In this article, we analyze the consequences of uncontested elections on lawmaking activity. Our primary hypothesis is that legislators who run unopposed are less active lawmakers than those who were selected through competitive elections. Studying roll‐call vote participation and bill introduction and enactment for most of the U.S. states for 1999–2000, we find that state legislators elected in unopposed elections perform more poorly compared to their colleagues elected in competitive contests.     

Uncertainty and Roll‐Call Voting in Lame‐Duck Sessions of the U.S. House, 1969–2010

Lame‐duck sessions of Congress have become increasingly common of late. Such sessions are marked by higher levels of ideological and participatory shirking among departing members, creating a more uncertain legislative environment. I investigate the consequences of such shirking on coalition formation and roll‐call behavior. I analyze House roll‐call votes held in the 12 congresses that convened lame‐duck sessions from 1969 to 2010 (91st to 111th Congresses) to assess how roll‐call behavior changes across sessions. I find subtle but statistically significant changes across sessions consistent with claims regarding greater uncertainty in roll‐call voting in lame‐duck sessions.     

Comparing NOMINATE and IDEAL: Points of Difference and Monte Carlo Tests

Empirical models of spatial voting allow us to infer legislators' locations in an abstract policy or ideological space using their roll‐call votes. Over the past 25 years, these models have provided new insights about the U.S. Congress, and legislative behavior more generally. There are now a number of alternative models, estimators, and software packages that researchers can use to recover latent issue or ideological spaces from voting data. These different tools usually produce substantively similar estimates, but important differences also arise. We investigated the sources of observed differences between two leading methods, NOMINATE and IDEAL. Using data from the 1994 to 1997 Supreme Court and the 109th Senate, we determined that while some observed differences in the estimates produced by each model stem from fundamental differences in the models' underlying behavioral assumptions, others arise from arbitrary differences in implementation. Our Monte Carlo experiments revealed that neither model has a clear advantage over the other in the recovery of legislator locations or roll‐call midpoints in either large or small legislatures.     

Party Unity,Ideology, and Polarization in Primary Elections for the House of Representatives: 1956–2012

Increasing party polarization in Congress is a vexing phenomenon for political scientists, as it offers a theoretical conundrum. Members of Congress have become increasingly ideologically divided by party in recent years, which seems counterintuitive as the public electorally punishes representatives for excessive partisanship and ideological behavior. One explanation for this result is that members receive benefits for such behavior during primaries. This article examines the effect of ideological and partisan behavior on primary challenges and primary vote totals for incumbent House members. The results show that incumbents receive benefits in the primary from greater levels of partisanship but not greater levels of ideological extremity. This finding is substantively important as it provides further insight into the motivation of congressional incumbents and offers a partial explanation for the rise in congressional polarization.     

In Search of Killer Amendments In the Modern U.S. House

Numerous studies have examined the incidence of killer amendments in Congress, but most of these studies have been either case specific, focusing on the legislative maneuverings around a single issue or bill, or temporally limited, focusing on strategic activity in only one or two Congresses. In this article, we present the beginning of a comprehensive research agenda for the systematic study of killer amendments. Using roll‐call data from the 83d through the 108th U.S. House (1953–2004), we identified those bills that (a) were successfully amended and (b) subsequently went down to defeat, a necessary condition for the existence of a killer amendment. We then examined these cases in greater detail, using both spatial analyses and case studies. Our analysis uncovered five cases, four of which are new, that appear to have the characteristics of true killer amendments, thus setting the stage for future analyses across time and legislative chambers and bodies.     

Legislative Voting Behavior,Seen and Unseen: A Theory of Roll‐Call Vote Selection

The empirical study of legislative behavior largely relies on roll‐call vote analysis, but roll‐call votes in many legislatures represent only a sample of legislative votes. We have good reasons to believe this sample is particularly poor for inferring party effects on legislative behavior. The selection of votes for roll call may be endogenous to exactly the characteristics of voting behavior (for instance, party cohesion) that we want to study. We must understand the roll‐call vote institution and account for its selection effects before we can draw inferences about legislative behavior from roll‐call results. This article develops a game‐theoretic model of roll‐call vote requests predicated on party leaders requesting votes to enforce party discipline. The model offers general and testable predictions about the selection process and how it affects observed and unobserved legislative voting behavior, particularly party cohesion.     

Strategic Retirements: The Influence of Public Preferences On Voluntary Departures from Congress

Are members of Congress responsive to public preferences in their decisions to seek reelection or retire, or do members simply rely on the advantages of incumbency to secure reelection? I argue that members of Congress consider their electoral vulnerability when deciding whether or not to seek reelection, informing their reelection odds with the same short‐term electoral forces that influence election outcomes: partisan preferences, economic evaluations, and congressional approval. Considering aggregate rates of voluntary departures from the House and Senate from 1954 to 2004, I show that rates of retirement reflect, not only institutional environments within Congress, but also the mood of the electorate.     

Congressional Performance,Incumbent Behavior,and Voting in Senate Elections

Conventional wisdom suggests that individual members of Congress have no real incentive to act in ways that might improve public evaluations of their collective body. In particular, the literature provides no clear evidence that public evaluations of Congress affect individual races for Congress, and little reason to expect that voters would hold specific individuals responsible for the institution's performance. We suggest that this conventional wisdom is incorrect. Using multiple state‐level exit polls of Senate voting conducted by Voter News Service in 1996 and 1998, we arrive at two key findings. First, we find that evaluations of Congress do have a significant effect on voting within individual U.S. Senate races across a wide variety of electoral contexts. Second, we find that punishments or rewards for congressional performance are not distributed equally across all members, or even across members of a particular party. Instead, we find that the degree to which citizens hold a senator accountable for congressional performance is significantly influenced by that senator's actual level of support for the majority party in Congress, as demonstrated on party votes.     

Congressional Party Defection in American History

In this paper, we analyze the roll‐call voting behavior of House and Senate members who changed party affiliation during the course of their political careers. We analyze members who switched during the stable periods of the three major two‐party systems in American history: the Federalist‐Jeffersonian Republican system (3d to 12th Congresses), the Democratic‐Whig System (20th to 30th Congresses), and the Democratic‐Republican System (46th to 106th Congresses). Our primary findings are that the biggest changes in the roll‐call voting behavior of party defectors can be observed during periods of high ideological polarization and that party defections during the past 30 years are distinct from switches in other eras because of high polarization and the disappearance of a second dimension of ideological conflict.     

Bicameralism and Minority-Party Influence on Legislative Development: Evidence from House Standing Committee Votes

The ability of the minority party to influence legislation in Congress is debated. Most bills are passed with large bipartisan majorities, yet the House, where most legislation is developed, is seen as a majority-party-dominated institution. I develop a theory of House minority-party influence at the committee markup stage as a result of the Senate’s institutional rules. An original data set of congressional committee votes shows that minority-party support in House committees predicts House and Senate passage. During unified party control of the chambers, an increase in Senate majority-party seats results in lower minority-party support for the legislation in the House committee, while during divided party control of Congress, the House majority passes more extreme bills as the chambers polarize. Even in the majority-party-dominated House, the minority’s preferences are incorporated into legislation, and the Senate’s institutional rules moderate bills to a significant degree.     

Senate Apportionment as a Source of Political Inequality

Political scientists have long known that the equal representation of states in the U.S. Senate and the placement of state lines might disadvantage politically relevant groups, granting some citizens greater voting weight in the chamber. Yet we lack systematic, longitudinal evidence that identifies the groups disadvantaged by Senate malapportionment, the sources of this disadvantage, and probes the policy consequences. In this article, I compare each state's liberalism and racial composition with its relative voting weight in the Senate over time. Additionally, I examine whether roll‐call coalitions in the Senate map onto these patterns of state ideology and racial composition.     

Slavery,Partisanship, and Procedure in the U.S. House: The Gag Rule, 1836–1845

From the 24th through the 28th Congresses, the House of Representatives operated under versions of a “gag rule” that blocked petitions dealing with abolition and related matters. This article presents the gag rule as not only a historically important window into slavery deliberations in Congress but also a case study in majority party restrictions of minority rights—and in the boundaries that constituency politics can place on majority power. Through analysis of vote choices and voting changes over time, I demonstrate that the gag rule's partisan origins gave way as northern members voted against party and with specific constituency pressures as well as general sectional sentiment. The gag rule shows the power of electoral considerations and constituency in the early U.S. House, and it also illustrates the force that constituency can have over majority procedural maneuvering.     

Tarnishing Opponents,Polarizing Congress: The House Minority Party and the Construction of the Roll‐Call Record

Existing research on congressional parties tends to focus almost exclusively on the majority party. I argue that the inattention to the House minority party hampers our understanding of the construction of the roll‐call record and, consequently, our understanding of the sources of polarization in congressional voting. Employing an original data set of House members' requests for recorded votes between 1995 and 2010, I demonstrate that votes demanded by the minority party are disproportionately divisive and partisan and make Congress appear considerably more polarized based on commonly used measures. Moreover, minority‐requested votes make vulnerable members of the majority appear more partisan and ideologically extreme.     

Evangelizing Congress: The Emergence of Evangelical Republicans and Party Polarization in Congress

The realignment of evangelical voters is well‐documented, but religion's impact within Congress is less clear. New data on home churches of members of Congress shows that the realignment of congressional evangelicals, combined with their growth and distinctly conservative legislative behavior, has significantly contributed to party polarization in Congress. Controlling for other factors, evangelicals are significantly more conservative than members of other religious traditions. This conservatism also has second‐order effects on the polarization of the House, where their more partisan proposals comprise a larger share of the roll‐call agenda when Republicans are in the majority. Moreover, evangelical Republicans in Congress differ significantly from evangelical Democrats in terms their geography, denominations, and experiences prior to Congress.