winning at the polls and in the polls: the incumbency advantage in surveys of u.s. house voters

Electoral Studies,Vol. 17, No. 4, pp. 443–461, 1998Pergamon 1998 Elsevier Science Ltd. All rights reserved

Printed in Great Britain0261-3794/98 $19.0010.00

PII: S0261-3794(98)00012-2

Winning at the Polls and in the Polls: theIncumbency Advantage in Surveys of U.S.

House Voters

Franco Mattei

Department of Political Science, SUNY at Buffalo, Buffalo, New York, NY 14260, USA

The success of House incumbents at the polls is well known and has been studiedextensively. This paper focuses on the incumbents’ successin the polls: the supportbestowed upon incumbents by survey respondents is substantially higher than thatreceived from the voters. The incumbency advantage at the polls, estimated at about10% in the most recent elections, is almost doubled when measured in the polls. Thedata, drawn from the 1982–1996 National Election Studies, show that respondents donot reward all winners; candidates elected to open seats have not benefitted from thekind of bounce consistently enjoyed by winning incumbents. In addition, the patternof respondents’ misreports appears to be inconsistent with earlier explanations basedon instrument effects. Respondent bias should be accounted for in order to reachcorrect estimates of the incumbency advantage in individual-level data. 1998Elsevier Science Ltd. All rights reserved

Keywords: U.S. house elections, incumbency, measurement error, response bias,national election studies

Introduction

Over the past two decades, the study of U.S. congressional elections has been increasinglyfocused on the influence of “local” forces on voting behavior. Taking advantage of a newsurvey design introduced in the 1978 National Election Study (NES), researchers have beenable to expose the underpinnings of the power of incumbency: the ability of incumbents toprevent strong challengers from entering a race, and their success in beating, usually bycomfortable margins, the candidates who choose to run for their seats.1 While the new datamade possible an in-depth analysis of voters’ perceptions and evaluations of congressionalcandidates, there has been a growing awareness that survey-based estimates of the incumbencyadvantage since 1978 are polluted by respondents’ systematic overreporting of preferences forsitting representatives. For instance, according to one study of the 1978 NES, this pro-incum-bent post-election rally amounted to more than 11% (Eubank and Gow, 1983),surpassingtheincumbency advantage estimated from actual voter preferences (Gelman and King, 1990; Coxand Katz, 1996); a whopping 54% of challenger partisans allegedly defected to House incum-

444 Winning at the Polls and in the Polls

bents. The unprecedented discrepancy between observed and reported levels of electoral sup-port for congressional candidates appeared to be due to respondents’ rather than sampling bias(Eubank and Gow, 1983).

The persistence and the magnitude of overreporting in later national surveys has called intoquestion the validity of the results of voting behavior studies based on the NES and, in parti-cular, conclusions about the relative importance of local and national forces in explainingcandidate choice. Box-Steffensmeier and Jacobson (1995, p. 8) find evidence of a “post-electionbandwagon for the victorious Republicans of extraordinary proportions. This recommends abit of caution about using 1994 survey data to assess the real magnitude of opinion shifts tothe Republican side.” In her review of a recent book on Senate and House elections, Fowlerpoints out that the author “ignores the controversy in the literature over how much the substan-tial overreporting of the vote for winning Senate candidates has biased the results towardincumbents. This is a critical omission, given his attempt to assess the strength of variousinfluence on election outcomes.” (Fowler, 1995, p. 1025) Indeed, Wright showed that biasedvote reports “yield a larger estimate for incumbency-related variables and a smaller estimatefor the impact of presidential choice” (Wright, 1990, p. 560); he concluded that “the resultswe obtain from the corrupted data are not close enough to the original (true) data to be usable:the errors in vote choice seriously alter the conclusions.” (Wright, 1993, p. 312).

Of course, this kind of measurement error has implications for other important substantiveissues, such as the correct determination of the influence of partisanship and the level of split-ticket voting. Defections among challenger partisans — one of the hallmarks of the electoraledge enjoyed by sitting representatives — may be artificially inflated. At times, NES datasuggested that challenger partisans’ choices were not far from being the result of “tossing afair coin in the voting booth.” (Cover, 1977, p. 536)2 Of course, one is left to wonder to whatextent these figures are affected by respondents’ misreporting. A comparison of exit poll andNES data uncovered a very large discrepancy in reports of split-ticket behavior among voterssharing the party identification of challengers (Wright, 1990).

This paper reviews the results of previous investigations on the congruence between reportedand actual outcomes of House races, and presents data on the eight most recent elections. Newevidence is used to gauge changes in the size and direction of vote misreports, and to retestsome of the hypotheses offered to explain the errors observed in earlier years. The analysisdemonstrates that support for winning incumbents has been substantially higher among respon-dents than among voters. On the other hand, the respondents’ propensity to rally around elec-tion winners does not extend to open seat contests, and appears less sensitive than expectedto questionnaire design or time of interview. Finally, although respondents show a penchantfor punishing losing challengers, the size of the pro-incumbent bias in the polls increases withthe margin of victory at the polls for Republican but not Democratic winners. Yet, the evidencefrom the last eight House elections also shows that voters’ familiarity with candidates appearsto account for the aggregate level of bias in favor of Democratic incumbents while failing toexplain overreports for Republican incumbents.

Differences between Election Results at the Polls and in the Polls: Explanations

Discrepancies between election results observed at the polls and candidate preferences reportedin post-election polls could be attributed to any of a number of problems related to the collec-tion of survey data.

445Franco Mattei

Sampling

Several students of the 1978 election analyzed the degree to which the congressional districtssampled by the NES provided a close approximation to the universe of congressional districtsand a valid basis for generalization about the incumbency advantage. Differences betweensurvey and actual results may be due to an unrepresentative sample of districts included inthe NES. As it happens, the House districts sampled in 1978 overrepresented races with bothunderfinanced challengers and winning incumbents (Mann and Wolfinger, 1980; Jacobson,1981; Eubank and Gow, 1983); on the other hand, Gow and Eubank (1984) report that the1982 NES included districts with an unusually competitive lot of challengers. As expected,the percentage of the vote received by incumbents was higher in the sampled districts than inthe nonsampled districts in 1978, but lower in 1982. If sampling is the source of the differencebetween candidate preferences at the polls and in the polls, the respondents’ declared choicesshould match the distribution of the vote in the sampled districts. Indeed, the introduction inthe 1978 NES of the ballot card format listing the names of the candidates for the major racesin the districts was specifically designed to approximate the conditions faced by the voters inthe booth, and to generate sample estimates very close to the universe parameters. The obvi-ously unintended consequence of such critical change was theincreasedoccurrence of voters’misreports of their candidate preference.3

Respondents’ Misreports

In addition to or instead of sampling problems, the discrepancy between actual and sampleresults may be caused by respondents’ misreports of their vote choice. Misreports may produce:

Partisan Bias Eubank and Gow noticed that in 1978 and 1980 “the bias towards Democraticincumbents is largely offset by the bias towards Republican incumbents” (1983, p. 137) sothat the partisan distribution of reported votes fell within 3 percentage points of the observedpartisan outcomes in the sampled districts. The partisan direction of the respondents’ claimedpreferences has not been subsequently analyzed. In light of the research community’s interestin the electoral success of incumbents, attention has been focused on the status (incumbentvs. nonincumbent) rather than the party (Democratic vs. Republican) of the candidates receiv-ing inflated support. Yet, the results of the analysis will show that incumbents’ partisan affili-ation needs to be considered in the study of vote misreports.

Pro-incumbent vs. Pro-winner BiasThe decline in party-line voting in House elections duringthe last three decades has been accompanied by defections towards incumbents. Eubank andGow (1983) and Gow and Eubank (1984), however, found that many defections reported inthe 1978–1982 National Election Studies could be accounted for by a marked pro-incumbentbias in the respondents’ declared vote choice. Their evidence indicates that:

(1) in the 1978 midterm, the pro-incumbent bias (11.5%) was about the same in Republicanand Democratic districts; it also was unaffected by the marginality of the districts, andpersisted among the subset of validated voters. The reported vote in open districts, how-ever, accurately matched the aggregate returns,

(2) in the presidential election year of 1980, the pro-incumbent bias declined to 5.5% but was,again, virtually unaffected by the partisanship of the incumbents or the marginality ofthe districts,


(3) in 1982, the average pro-incumbent bias was found to be 9.1%, and the authors rejectedthe hypothesis of a pro-winner bandwagon effect because reported and aggregate resultsin open districts were again very close: “This demonstrates that the bias occurs if, andonly if, respondents are asked about the incumbent running for reelection in their district.”(Gow and Eubank, 1984, p. 229).4

Wright’s analysis of the 1988 Senate Election Study led him to conclude that overreportingwas neither constant across districts nor to the advantage of incumbents alone; rather, bias wasproportional to awinner’smargin of victory. The hypothesis of a pro-incumbent bias was thusdiscarded: “Whatever is causing an overreport of the vote in incumbent contests seems alsoto be working in open-seat races.” (Wright, 1992, p. 552) Furthermore, this pro-winner biasseemed to fit a ‘spiral of silence’ model (Noelle-Neumann, 1993) rather than conform to a fixedbandwagon effect. Some respondents, perhaps “dreading isolation more than error, professed toshare the sentiments of the majority,”5 and appeared to abandon election losers as the winner’smajority grew in size.

Wright’s subsequent analysis of House voting from 1952 to 1988 based on NES data con-firmed his early findings but only some of the conclusions reached by Eubank and Gow.Respondents’ reports yielded a sizable overestimate of House winners’ support after 1978.6

The magnitude of the bias, however, was not smaller in presidential than in midterm years,nor was the bias limited to incumbents: “some respondents do ‘switch’ their support to thewinner — apparently in about equal proportions for incumbents and open seat victors.” (1993,p. 306).7

Instrument and Time Effects

Eubank and Gow identified the new survey format introduced in 1978 as the main culprit ofthe pro-incumbent bias they uncovered between that year and 1982. In particular, the sequenceand content of questions leading to the vote preference appeared to predispose respondents,especially the least interested and involved, toward the incumbents. In the 1978, 1980 and1982 NES, these questions dealt with the contacts voters or their families had with incumbentsand challengers, the reasons for these contacts, the degree of satisfaction with the incumbent’sperformance, the incumbent’s reputation for being helpful, and the incumbent’s voting behavior(in 1978 and 1982). “During the course of a typical interview, the interviewer will mentionthe House incumbent’s name about a dozen times, and will indirectly identify the incumbentas ‘he’ or ‘she’ many more times... The ‘incumbency’ questions contribute to the incumbencyeffects, which they were designed to explore, because they are placed before the questionasking respondents for whom they voted. These questions provide information about the incum-bent, and thereby prompt voters to subsequently report that they voted for their representative.”(Eubank and Gow, 1983, p. 132–3) Questions about challengers were fewer and made referenceto those “who also ran for the House of Representatives from this district in the last election”whereas questions about the incumbent made clear that (s)he “has been a U.S. representativefrom this district.” The strength of the alleged bias seemed to be somewhat reduced in presiden-tial election years when the main survey emphasis was on the race for the White House.

Under this hypothesis, one should expect overreporting to benefit all incumbents, regardlessof their party. Indeed, Eubank and Gow emphasized this across-the-board effect in their analy-sis of the 1978–82 NES, even though declared preferences for Democratic incumbents wereespecially inflated in 1982: upward bias in support of Democratic and Republican incumbents

447Franco Mattei

was 11.1 and 7 percent, respectively. Finally, their data were consistent with the hypothesisthat the magnitude of overreporting was contingent on the type of election: higher in midtermyears (1978 and 1982) than in presidential years (1980).

Wright’s analysis did not find convincing support for these kinds of instrument effect. Inthe 1984 post-election survey, all but the recall questions about the congressional candidatesrunning in the districts were placedafter the vote item, thereby removing the suspected sourceof pro-incumbent bias. Yet, according to Wright’s figures, bias in favor of winners (most ofwhom were incumbents) in 1984 was higher than it had been in 1982 and 1980.

The sequence and wording of NES questions preceding the voting section have undergonefurther changes since 1984, providing an opportunity to test their alleged impact. Between1986 and 1990, only questions about the types of contacts between the respondents and thecandidates came before the vote item; the number of these questions was the same for incum-bent and challenger, but they still began with mentions of the “U.S. representative in Wash-ington,” and the individual “who also ran for the House of Representatives,” respectively. In1992 and 1994 the same battery of questions about the contacts between respondents andcandidates preceded the vote item, but incumbents were no longer identified as such by theinterviewers, nor were the challengers identified as those “who also ran.” In 1996 these ques-tions were eliminated altogether.8 Therefore, to the extent that question wording and order arethe main explanation of voters’ misreports, pro-incumbent bias should be higher in 1982 thanin 1986–90, and should benefit incumbents of both parties about equally. In 1984, 1992, 1994,and 1996 overreporting of the incumbents’ vote should become rare or disappear.

Yet, another feature of the NES questionnaires used since 1978 might tip some respondentstowards all winners and thus produce overreporting in favor of those elected to office in openas well as incumbent-held districts. This effect stems from the ballot card format carrying thenames of the candidates and allowing the identification of winners and losers at the time ofthe interview. A pro-winner (rather than pro-incumbent) bias might result from switches —whether intentional or caused by memory lapses — among the least knowledgeable and com-mitted voters in response to the post-election information typically favorable to successfulcandidates. Wright’s analysis of Senate and House races held after 1978 found some evidenceof overreporting growing as the number of days between the election and the interviewincreased. This time effect appeared to be made possible by the ballot card format: “as thedays pass from the election, and perhaps memory of their vote fades, it seems respondents’impressions of candidates are triggered by the names provided on the ballot question, andthese vote reconstructions yield increasing overreports for the winner.” (Wright 1993, p. 309)9

In House races, however, a sizable and significant pro-winner bias was detected even on elec-tion day, a phenomenon hardly attributable to flawed recall; overreporting taking place immedi-ately after the vote or in a compressed time frame would seem to be the product of the desireto jump on the bandwagon rather than the result of memory failure. In any event, the presenceof nontrivial misreporting right after the vote, whatever its origin, appears to cast some doubton the effectiveness — leaving aside the feasibility — of new, election-day data collection bythe NES. Moreover, the persistence of overreporting under alternative question sequences lead-ing to the vote item seems to blunt hopes about the benefits of further changes in that particularaspect of survey design.

In summary, research on discrepancies between actual and reported vote choice in Houseelections has shown the existence of marked misreporting contaminating findings and weaken-ing claims about voters’ choices at the polls. Several hypotheses regarding the source of errorshave been raised, but disagreement remains about the nature and roots of the phenomenon. In


the following sections, data on contested House races between 1982 and 1996 are used totackle and clarify the lingering issues outlined above.

Data

The data presented in the next section show the outcomes of the 1982–1996 House electionsin contested districts (universe) according to the official results published in several issues ofCongressional Quarterly Weekly Report(only votes received by the two major party candidatesare used in the computations); the election results in the subset of contested districts sampledby the NES (sample); the partisan division of the vote, the support for incumbents, challengersand winners as reported by the NES respondents (validated records are available for 1984,1986, 1988 and 1990; they are not used here because they do not depart markedly from self-reports). These data are broken down by the type of race: whether occurring in open districtsor incumbent-held districts. The number of congressional districts sampled by the NES variesbetween 92 in 1990 and 198 in 1996, corresponding to 26% and 48%, respectively, of thetotal number of contested districts; the number of reported voters ranges from 611 in 1990 to1276 in 1992. The number of reported voters in open districts is typically quite low. In the1988 NES there are only 68 voting respondents in 6 open seats; the highest number of reportedvoters, 242, is found in 1992 when 34 open races were sampled.10

Results

Sampling

The first issue to be addressed has to do with the types of districts included in the NES, andwhether they are representative of the universe of districts in play in each election year. Table1 displays the distribution of votes and voters in the universe of contested House races between1982 and 1996, and equivalent data for the subset of congressional districts included in theNES. The table also shows respondents’ reported preferences for party candidates, incumbentsand winners.11

Incumbent-held Districts The NES have systematically oversampled Democratic districts andvoters represented by Democratic incumbents. This sampling bias was particularly strong in1984 when Democratic districts were 54.8% of the universe but 64.8% of the sample; 57.5%of voters but 69.3% of respondents were represented by a Democratic incumbent. The smallestbias is observed in the two most recent elections; in 1996 and 1994, the differences betweenuniverse and sample percentage of Democratic districts and voters represented by Democraticincumbents were at most 1%.

The electoral performance of incumbents and winners is only slightly stronger in the sampleddistricts than in the universe; only in 1982 is the reverse true. The largest difference is foundin 1988 when sampled incumbents and winners ran ahead of their classes by about 2%; moretypically, and with the noted exception of 1982, the mismatch between sample and universeis around 1%.12 Sample selection does not produce strong and systematic partisan distortions;while in 1994 and 1988 Democratic incumbents outperformed Republican incumbents by 2.7%(e.g.: in 1994 Democratic incumbents in the sample received 2.1% more than all party incum-bents whereas GOP incumbents sampled by the NES received 0.6% less than all GOPincumbents), in other years the sample-universe difference across party lines was smaller.

449Franco Mattei

Tab

le1.

Con

test

edho

use

elec

tions

inth

ena

tion

and

inth

eN

ES

sam

ples

,19

82–1

996

1996

1994

1992

1990

Sam

pled

dist

ricts

All

Sam

pled

dist

ricts

All

Sam

pled

dist

ricts

All

Sam

pled

dist

ricts

All

cont

este

dco

ntes

ted

cont

este

dco

ntes

ted

dist

ricts

dist

ricts

dist

ricts

dist

ricts

NE

SaO

bser

ved

NE

SaO

bser

ved

NE

SaO

bser

ved

NE

SaO

bser

ved

A)

All

cont

este

ddi

stric

ts19

840

9b

146

382c

154

386d

9234

9e

Dem

ocra

ticdi

stric

ts77

(38.

9)15

8(3

8.6)

81(5

5.5)

208

(54.

5)80

(51.

9)19

2(4

8.5)

58(6

3.0)

200

(57.

3)R

epub

lican

dist

ricts

97(4

9.0)

200

(48.

9)45

(30.

8)12

2(3

1.9)

40(2

6.0)

120

(30.

3)26

(28.

3)12

1(3

4.7)

Ope

ndi

stric

ts24

(12.

1)51

(12.

5)20

(13.

7)52

(13.

6)34

(22.

1)84

(21.

2)8

(8.7

)28

(8.0

)Lo

sing

incu

mbe

nts

11(6

.3)

20(5

.6)

11(8

.7)

34(1

0.3)

9(7

.5)

19(6

.1)

3(3

.6)

14(4

.4)

Vot

esfo

rR

ep.

Can

dida

tes

53.0

49.6

50.2

51.7

50.4

51.7

40.9

46.0

47.1

38.1

44.3

46.5

(N)

986

848

1276

611

B)

Incu

mbe

nt-h

eld

seat

sV

oter

sin

Rep

.di

stric

ts57

.759

.059

.337

.238

.439

.031

.335

.340

.131

.934

.741

.2V

otes

for

Dem

.in

cum

bent

s71

.268

.267

.264

.062

.059

.974

.564

.063

.382

.666

.164

.9V

otes

for

Rep

.in

cum

bent

s74

.061

.862

.176

.168

.368

.670

.764

.363

.473

.562

.662

.2V

otes

for

all

incu

mbe

nts

72.8

64.4

64.2

68.5

64.4

63.3

73.3

64.1

63.3

79.7

64.9

63.8

Vot

esfo

ral

lw

inne

rs72

.864

.964

.673

.365

.164

.174

.964

.863

.881

.165

.164

.1(N

)90

069

410

3453

3C

)O

pen

seat

sV

otes

for

Rep

.ca

ndid

ates

32.3

50.4

50.6

55.2

55.1

54.5

45.9

46.0

45.4

57.7

49.7

48.7

Vot

esfo

ral

lw

inne

rs54

.657

.658

.660

.259

.058

.158

.860

.359

.761

.558

.859

.0(N

)86

154

242

78


Tab

le1.

Con

tinue

d

1988

1986

1984

1982

Sam

pled

All

Sam

pled

All

Sam

pled

All

Sam

pled

All

dist

ricts

cont

este

ddi

stric

tsco

ntes

ted

dist

ricts

cont

este

ddi

stric

tsco

ntes

ted

dist

ricts

dist

ricts

dist

ricts

dist

ricts

NE

SO

bser

ved

NE

SO

bser

ved

NE

SO

bser

ved

NE

SO

bser

ved

A)

All

cont

este

ddi

stric

ts98

352f

128

360

108

132g

373h

Dem

ocra

ticdi

stric

ts58

(59.

2)18

5(5

2.6)

68(5

3.1)

177

(49.

2)70

(64.

8)18

5(5

2.6)

62(4

7.0)

164

(44.

0)R

epub

lican

dist

ricts

34(3

4.7)

143

(40.

6)46

(35.

9)14

2(3

9.4)

29(2

6.9)

143

(40.

6)51

(38.

5)15

2(4

0.7)

Ope

ndi

stric

ts6

(6.1

)24

(6.8

)14

(10.

9)41

(11.

4)9

(8.3

)24

(6.8

)19

(14.

4)57

(15.

3)Lo

sing

incu

mbe

nts

2(2

.2)

6(1

.8)

1(0

.8)

6(1

.7)

2(2

.0)

6(1

.8)

6(5

.2)

23(6

.2)

Vot

esfo

rR

ep.

Can

dida

tes

42.8

45.1

48.6

46.5

45.6

47.3

48.0

46.8

50.3

43.5

45.2

46.2

(N)

821

792

1083

621

B)

Incu

mbe

nt-h

eld

seat

sV

oter

sin

Rep

.di

stric

ts35

.540

.646

.247

.842

.846

.530

.530

.742

.548

.045

.050

.1V

otes

for

Dem

.in

cum

bent

s78

.671

.568

.379

.770

.669

.769

.765

.563

.677

.467

.968

.6V

otes

for

Rep

.in

cum

bent

s78

.768

.367

.874

.966

.565

.879

.770

.868

.864

.860

.160

.5V

otes

for

all

incu

mbe

nts

78.6

70.2

68.0

77.4

68.9

67.9

72.8

67.1

65.8

71.3

64.3

64.5

Vot

esfo

ral

lw

inne

rs78

.270

.268

.277

.168

.968

.073

.467

.366

.171

.364

.465

.0(N

)75

369

996

952

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)O

pen

seat

sV

otes

for

Rep

.ca

ndid

ates

54.4

51.1

51.0

47.3

48.5

50.9

70.2

58.4

52.6

48.1

47.7

47.7

Vot

esfo

ral

lw

inne

rs66

.264

.859

.162

.461

.759

.768

.459

.257

.848

.162

.260

.0(N

)68

9311

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Finally, the NES has undersampled losing incumbents; their number is lower than expectedin 5 of the 8 surveys (1996, 1994 and 1988 being the exceptions), but the number of districtsand respondents involved is miniscule.

Open Districts The percentage of open seats included in the NES closely tracks the percent-age of open races in the nation; the number of sampled districts is generally small, varyingbetween 34 in 1992 and 6 in 1988. Winners did better in the sampled districts than in theuniverse in all surveys but 1996 and 1990. The most notable mismatches between sample andoverall results are probably affected by the limited number of cases. The 1984 NES, forinstance, includes a very unusual collection of open races dominated by GOP candidates. Thetwo Democratic winners were successful in very competitive elections, receiving 50.3% and53.4% of the major party vote, but none of the Republican winners was elected with less than56% of the vote. Similarly, four of the six open seat winners in the 1988 NES received atleast 65% of the two-party vote; one other, less lopsided race (56% to 44%) had the lowestturnout by far. As a result, the average support for the six sampled victors is almost 6% higherthan that for all 24 winners in contested open seats.

In summary, a review based on data for the past eight House elections shows that the NEStend to oversample districts with Democratic incumbents whose performance at the polls is,with one modest exception, better than average. On the other hand, the relatively few opendistricts sampled by the NES between 1982 and 1996 display a slight Republican slant. Hence,the percentage of the major party vote going to Democratic candidates is always higher in thesampled districts; this upward deviation varies between 3.5% (in 1984 and 1988) and 0.6%(in 1996). Overall, however, there is a rather close correspondence between districts in theNES samples and in the universe. Large differences are rare, and they tend to coincide withsmall sample size.

Respondents’ Misreports

The comparison of election results in the polls (“NES”) and at the polls (“Observed”) insampled districts shown in Table 1 provides a strong indication of the magnitude and directionof respondents’ misreports. In particular, the mean level of support for incumbents appearssystematically inflated in survey reports. However suggestive, comparing cross-sectional sam-ple averages to national mean results is not the most appropriate measure of bias. The relevantunit of analysis in the study of House elections is the congressional district, and the distributionof respondents across sampled districts does not match the distribution of voters. Thus, a betterapproach is to compare the expected district vote for a party defined by the actual electionoutcome to the vote for the same party based on the respondents’ declared preferences. Table2 shows the weighted (by the number of respondents in each contested district) average of thegap between the electoral performance at the polls and in the polls for party candidates, incum-bents and winners.

Partisan Bias In five of the eight election years, the partisan difference between reportedand expected House vote does not appear to be particularly large; it ranges from a pro-Republi-can 0.3% in 1994 to a pro-Democratic 1.6% in 1982. In 1990 and 1992, a more robust pro-Democratic bias of respectively 4.7% and 4.3% is observed; in 1996, the small pro-Republicandistortion observed 2 years earlier is inflated to 2.9%. Some overestimates would appear tobe larger had the baseline shown in Table 1 been chosen, and even larger had the “unusual”


Table 2. Differences between observed and expected house election results, 1982–1996

1996 1994 1992 1990 1988 1986 1984 1982 Average

A) All contested districtsPartisan biasPro-Democratic −2.9 −0.3 4.3 4.7 0.8 1.1 0.3 1.6 1.2B) Incumbent-held seatsIncumbent biasDemocratic 4.2 3.7 11.6 14.7 7.6 8.5 5.9 10.0 8.3Republican 11.5 8.1 7.2 11.4 11.0 7.1 8.3 7.0 9.0All incumbents 8.4 5.3 10.2 13.7 8.8 7.8 6.7 8.6 8.7Winner biasAll winners 8.2 8.7 11.3 14.8 8.4 7.5 7.2 7.8 9.2C) Open seatsPartisan biasPro-democratic 17.3 1.4 −1.3 −7.1 −1.8 1.6 −10.5 −0.7 −0.1Winner biasAll winners −2.4 2.1 −2.5 6.9 3.1 2.4 8.6−13.3 0.6

Source: 1982–1996 National Election Studies.

nature of the sampled districts been neglected.13 In general, the aggregate error in the partisandivision of the congressional vote is modest and not unique; for purposes of comparison, themagnitude of the error in the partisan distribution of the presidential vote in recent electionshas displayed a similar range. Within the sampled congressional districts, the pro-Clinton biasin 1992 was 3.9% while overreporting for Bush in 1988 was 1.1%. More importantly, asshown below, partisan discrepancies are a derivative result of a much more egregious failureof respondents to provide an accurate portrait of their district’s choice between incumbentsand challengers.

Incumbent Bias Table 2 documents the existence of sizable and systematic overreporting infavor of House incumbents in every election held since 1982; the magnitude of this bias,however, varies across both years and parties. It is also quite clear that the amount of errorcannot be explained by misreports of those respondents who claimed that they voted but didnot; available validated data (not shown) confirm the large gap between the incumbents’ per-formance at the polls and in the polls. Furthermore, in the period under consideration, pro-incumbent bias is on average about as high in presidential years as it is in midterm years.Gow and Eubank found “the predicted V-shaped pattern, the base of the V corresponding tothe lesser bias in a presidential election year” (1984, p. 229) between 1978 and 1982; a similarpattern is barely apparent between 1982 and 1986, but absent afterwards.

Over the last eight elections, the average pro-incumbent bias is 8.7% (8.3% if validatedvoter reports are used for the 1984–1990 elections). Overreports for Democratic incumbentsare the most volatile, varying between 3.7% in 1994 and 14.7% in 1990, whereas overreportsfor Republican incumbents are somewhat less erratic, ranging from a 1982 minimum of 7%to a 1996 maximum of 11.5%. Over the 8-election period, however, the average overestimateof the vote for the two major party incumbents is virtually the same. Yearly partisan differencesin the size of the bias are seldom dramatic (the 1996 data represent the sharpest exception).In addition, they appear to bear only a faint relationship to the ebb and flow in the political

453Franco Mattei

success of the two major parties, and the likely emphasis of post-election coverage andinterpretations that might affect people’s responses to survey questions. Finally, some resultsprovide an extremely poor reflection of election outcomes. In 1990, sitting representatives ofboth parties scored landslide victories in the polls; preferences for incumbents running andwinning reelection are overestimated by almost 14 and 15 percentage points, respectively.These data are, of course, strikingly at odds with the actual midterm outcome in which incum-bents of both parties lost votes for the first time in any postwar election, despite generallyinexperienced and underfinanced challengers (Jacobson, 1997). Although the 1990 respondentsdisplay an unusually strong inclination to line up behind incumbents, their behavior is part ofa general pattern whereby the average incumbency advantage based on survey reports is nearlyas large as that estimated from voting records.14

Winner Bias In incumbent-held districts, the average pro-winner and pro-incumbent bias arevery close because very few incumbents lost their seats over the last eight elections. Amongrespondents who reportedly cast their vote in races lost by an incumbent between 1982 and1996, support for the winning challengers was more than 6 pointshigher than expected fromactual outcomes. In the far most typical instance of races won by incumbents, acknowledgedsupport for losing challengers was more than 9 pointslower than expected. This pattern ofmisreporting may suggest that respondents develop an inclination to widen winners’ share ofthe vote; declared preferences for incumbents would be inflated in the polls merely as a conse-quence of their success at the polls. Such hypothesis, however, lacks convincing empiricalbacking.

Given the rare occurrence of incumbent defeats,15 a 6-point difference reaches borderlinestatistical significance (p5 0.044). Moreover, as indicated in Table 2, only in 1994 is thewinners’ performance in the polls noticeably better than the incumbents’. The unusual gap ismostly due to reactions to the 11 losing Democrats sampled by the NES. Reported supportfor winning Democratic incumbents is 8 points higher than expected, the same overestimatebenefitting Republican incumbents. Exclusion of such an atypical election year (especially atthe polls, where Republican candidates won a majority of House seats for the first time in fourdecades), shrinks the difference between losers’ actual and reported vote to a trivial 2.5% (p5 0.53).

Analysis of open seat races allows a further test of whether overreporting benefits all electionwinners, irrespective of their status, and whether the gap between actual and reported vote isproportional to a candidate’s margin of victory. Even though the number of cases in opendistricts is relatively low, the available evidence does not point to a systematic bias in favorof all successful candidates, and supports only partially the anticipated relationship betweenthe size of the bias and the decisiveness of the election victory.

As shown in Table 2, over the last eight elections the mean overestimate of the winners’vote in the sampled open districts is less than 1% as opposed to 8.7% for incumbents —both winning and losing. The discrepancy between reported and expected preferences variesconsiderably across years, and is affected by the limited number of cases. On four occasions,it is within 2.5 percentage points, with respondents inflating winner support in two of fourinstances. Preferences for the 1982 winners are strongly underestimated (2 13.3%) whereasthe vote for the 1984 and 1990 winners is overestimated (8.6% and 6.9%, respectively). In1982 there is a pro-winner but not a partisan bias; in 1996, the reverse is true, while in 1984and 1990 the two biases overlap.16 When respondents in incumbent-held and open districts arepooled in two separate groups, support in the polls for winning incumbents was 9.1% higher


than expected while support for winning candidates in open seats was just 0.3% above expec-tations.17

The difference between overreporting in favor of open seat winners and successful incum-bents can be illustrated in two ways: graphically, and by means of regression analysis. In bothopen and incumbent-held districts, the proportion of the vote received by Republican candidatesin the polls can be plotted (on the vertical axis) against the proportion of the vote receivedby the same candidates at the polls (on the horizontal axis). Of course, the value on the ordinateis either 0 (Democratic vote) or 1 (Republican vote) when only one respondent stated hercandidate preference. In all other instances, we obtained the mean proportion of Republicanvotes based on survey reports within each district. With unbiased respondents, there shouldbe a close correspondence between declared and actual vote; in other words, a line with zerointercept and slope of one would provide a very good fit to the scatter of points. A visualinspection of the plots (not shown) suggests that this line represents a better fit for winningcandidates than for winning incumbents. In the latter case, in particular, when the expected(actual) Republican vote is above 0.5, most data points measuring the mean reported Republi-can support clearly fall above the line of no bias. This pattern, however, is much less apparentbelow 0.5; reported support for winning Democratic incumbents does not seem to be overesti-mated as much as verbal preferences for winning Republican incumbents are. Indeed, whenthe data are collapsed into 12 mutually exclusive classes, ordered from the lowest to the highestexpected Republican vote, the magnitude of overreporting for Republican incumbents followsa strong monotonic pattern. As the actual average Republican vote increases, so does upwardbias. On the other hand, while support for Democratic winners is always higher in the pollsthan at the polls, the level of bias is mostly flat; for example, declared support for Republicanchallengers receiving between 25% and 30% of the vote, and for Republican candidates losingby less than 5 points, is underestimated by about the same amount.

Confirmation of distinct overreporting patterns is found by regressing the respondent’sdeclared preference (15 Republican and 05 Democrat), on the observed proportion of thetwo-party vote actually received by Republican candidates in contested districts sampled bythe NES. Table 3 shows that while the estimates in open races are very close to the valuesexpected under the hypothesis of no bias (a zero intercept and a slope of one), the sameestimates computed in incumbent-held races depart significantly from their unbiased baselines.The negative constant coupled with a slope greater than unity suggest that the size of overre-porting in the polls grows with the margin of victory at the polls. This pattern, however, fitsRepublican and Democratic winners differently. An interaction term separating each party’sincumbents shows that the estimated slope exceeds unity among Republicans while fallingshort of it among Democrats. Of course, this difference could be due to the predominance ofDemocratic winners among the least competitive races (won by 75% of the vote or more) inwhich the size of the pro-incumbent bias suffers from a ceiling effect. When the analysis islimited to the most competitive districts, evidence of such effect is found in a steeper regressionline. Nevertheless, the discrepancy between the value of the slopes estimated for the incumbentsof the two parties remains strong and statistically significant. The results show that overreport-ing for Republican incumbents increases as their margin of victory at the polls becomes wider,whereas overreporting for winning Democratic incumbents is sizable (as indicated by theintercept) but virtually constant (the value of the slope is about 1).18

455Franco Mattei

Table 3. Regression of reported vote on actual vote for winning candidates and incumbents, 1982-1996

Winning Winning incumbents Winning incumbentscandidates all districts competitive districtsopen seats

Intercept −0.032 −0.215 −0.028 −0.299 −0.108(0.061) (0.014) (0.024) (0.019) (0.040)

Actual vote 1.064 1.424 1.180 1.579 1.308(0.118) (0.028) (0.038) (0.037) (0.062)

Interaction −0.371 −0.289(0.044) (0.057)

(N) 916 5865 4958

Note: The dependent variable is the reported vote for a Republican candidate (1= Republican, 0=Democratic). The actual vote is the proportion of the two-party vote received by a Republican candidatein a district.The interaction term is obtained by multiplying the actual vote times a dummy variable coded 1 forDemocratic winners, and 0 for Republican winners.Competitive districts are those in which the winner received at most 75% of the two-party vote.The equations were estimated via ordinary least squares with robust standard errors (in parentheses).Source: 1982–1996 National Election Studies.

Instrument and Time Effects

There is ample evidence supporting the influence of question wording and context on respon-dents’ answers (e.g.: Asher, 1995; Schuman and Presser, 1981). While changes in the surveyinstrument are likely to affect some respondents’ reports of their candidate preferences, theyhardly seem to provide a satisfactory explanation of the observed variance in the magnitudeand direction of bias.

This analysis of misreporting of the House vote in the 1982–96 NES offers evidence support-ing its pro-incumbent rather than pro-winner nature. Eubank and Gow believed that the mostcompelling reason for pro-incumbent overreports and the unprecedented level of defectionsamong challenger partisans after 1976 was to be found in the series of questions focused onthe incumbents and placed before the vote item. The partisan differences in the degree andpattern of overreporting shown in Tables 2 and 3 are difficult to reconcile with a hypothesizedfactor that treats, and supposedly favors, all incumbentsequally. The 1984 NES used a ques-tionnaire design that should have squelched pro-incumbent bias; while overall bias declinedby 2 points between 1982 and 1984, it still remained substantial at about 7%, and overreportingfor winning Republican incumbents increased from one election to the other. Between 1986and 1990, the voting section of the NES was once again preceded by several questions aboutcontacts with the candidate “who has been a U.S. representative in Washington.” The reintro-duction of these items potentially leading to a pro-incumbent bias coincides with overreportinghigher than in 1984; this increase, however, is neither uniform over the three election yearsnor the same for the two parties. In the questionnaires used in 1992 and 1994, House incum-bents were not identified by the interviewer in the series of probes about the contacts betweenrespondents and candidates; the latter were referred to as Democrats or Republicans, not asrepresenting or running in the district. Pro-incumbent bias did not vanish; despite the similarityin question wording and context, it was almost twice as high in 1992 as in 1994. In addition,even though question content and sequence made the 1992 and 1982 questionnaires, respect-


ively, the least and most biased in favor of House incumbents, overreporting was neverthelessmore frequent in 1992 than in 1982. Finally, declared preferences in 1996 show once again aselective advantage in favor of winning candidates who are incumbents (especiallyRepublicans) even when the type of questions alleged to generate that advantage, the contactitems, have been entirelyremovedfrom the survey.

These results demonstrate that some of the changes in question wording and order since 1982did not have the expected effects and did not substantially correct respondents’ misreports. Inaddition, while the evidence linking the rise of misreporting to the introduction of the ballotcard format appears clear and conclusive (cf. Jacobson and Rivers, 1993; Box-Steffensmeierand Jacobson, 1995), it has been argued that the new measurement instrument allows respon-dents to recognize and “reward”all candidates who won their election. Over the period underconsideration, however, winners of open seats have failed to reap the benefits systematicallyenjoyed by winning incumbents.

Furthermore, these benefits have emerged even from interviews taken immediately afterelection day. Fig. 1 shows the mean overestimate of the winning incumbents’ actual perform-ance at the polls for 15, consecutive 3-day periods following the vote; the length of theseperiods was meant to approximate the time needed to complete relatively short interviews insamples of the size typically contacted for the NES. Although the data indicate that the discrep-ancy between results at the polls and in the polls is above the overall mean overestimate (9.1%)in later periods, no clear tendency emerges over the entire time span.19 In particular, in inter-views completed within the first 3 days after the vote, winning incumbents had alreadyimproved over their election day results by 8.6%. In open seat races, where pro-winner biaslacks the size and consistency seen among incumbents, early interviewspenalizedwinners;their support in the polls underestimates the outcome at the polls during the first two 3-day per-iods.20

The 1996 NES affords another look at the influence of time of interview on overreporting.

Fig. 1. Time and overreporting of winning incumbents’ vote, 1982–1996

457Franco Mattei

For the first time, the pre-election wave of the 1996 NES asked respondents about their votingintention for the House race. The innovation makes it possible to compare the answer to thisquestion, when the identity of winners and losers is yet to be determined, to the actual districtvote. Support for incumbents was almost 11% higher than expectationseven before the electiontook place. Ironically, preferences for candidates who later won open seats were more than 7points above actual election results (the gap was only 2 points among respondents interviewedboth before and after the vote). Thus, availability of information about the outcome did notgenerate any rally around the victors. In particular, none of the respondents in districts whereincumbents went down to defeat switched away from their intended preference after the vote.

The Puzzle of Voter Misreports: Summary and Discussion

Analysis of reported vote preferences for House candidates in the 1982–1996 NES shows astrong and systematic bias averaging more than 9% in favor of winning incumbents. Winnersof open seats, however, were not the beneficiaries of the treatment accorded other successfulcandidates; on average, their support in the polls was barely above that earned at the polls.The introduction of the ballot card format in 1978 brought about a rise in the amount of votemisreporting, and the change in the survey instrument was presumed to create an advantagein favor of all winners. Yet, vote for open seat losers was not underestimated, and support forlosing incumbents only occasionally fell below expectations. The pro-incumbent bias allegedlygenerated by the wording and order of the questions preceding the vote item persisted and attimes increased when alternative question arrangements should have reduced or eliminated thatbias. While the level of overreporting was, on average, about the same for Republican andDemocratic incumbents, its distribution varied across party lines; only for Republicans wassuccess among voters related to success among survey respondents. Finally, errors in themeasurement of support for winning incumbents are not erased by purging the samples ofrespondents who claimed to have voted but for whom no voting record was found, or byconcentrating interviews in the few days immediately following an election. Indeed, the 1996NES demonstrates that preferences for incumbents were well overestimatedbeforea singlevote was cast and counted.

The results of the analysis draw a sharp distinction between races with and without anincumbent on the ballot. This suggests that the puzzle of respondent bias may find a partialsolution in what distinguishes the two types of House races. In particular, when a member ofCongress runs for reelection, voters are much more familiar with the incumbent than the chal-lenger; the latter suffers from a visibility gap in terms of both name recall and recognition.Between 1982 and 1996, 47% of voters recalled the name of the incumbent in their districtbut only 18% had recollection of the challenger’s name; 91% and 51% of the same respondentsrecognized the name of incumbents and challengers, respectively.21 This information imbalancemay help incumbents in the polls as well as at the polls if some voters declare a preferencefor the candidates who are cognitively more salient and accessible at the time of the interview.Before 1978, voters who did not recall the name of the candidates chosen on election daywere asked to remember their party affiliation; by listing the candidates’ names, the ballot cardmight have encouraged voter misreports in favor of the more familiar incumbents. Furthermore,if information imbalance lies at the root of misreports, recall and recognition of candidatesinvolved in open races or in the few elections lost by incumbents should be relatively evenin light of the absence of a consistent pro-winner bias in both instances. Indeed, between 1982and 1996, the recall differential between winners and losers in open races was about 10%, and


the recognition gap was slightly below 13%; in districts were incumbents were defeated, thechallengers’ recall and recognition deficits were about 5% and 6%, respectively.

While these overall figures are consistent with the hypothesized relationship between thedistribution of information about candidates and the occurrence of voter misreports in Houseelections, the pattern of results across election years does not fully fit expectations. With thecustomary warning that findings based on only eight data points should be approached andevaluated with caution, the evidence about the relationship between the skew in the informationimbalance and the level of pro-incumbent bias is mixed. Between 1982 and 1996, the corre-lation between the recall differential (percent recalling the incumbent’s name minus percentrecalling the challenger’s name) and the pro-incumbent bias is 0.77 in Democratic districts,but it is 0 in Republican districts. The correlation between the recognition differential and thepro-incumbent bias is lower: 0.48 in Democratic districts, and 0.30 in Republican districts.22

A similar outcome emerges with regard to recall and recognition of a challenger; over the pasteight elections, the anticipated negative relationship between pro-incumbent bias and famili-arity with the challenger is much stronger in Democratic than Republican districts. Other resultsdo not fully conform with expectations based on information imbalance. The size of the differ-ence between the expected and observed vote received by candidates carrying open seats is onlymoderately related to the value of the recall differential (r5 0.48), and virtually independent ofthe magnitude of the recognition differential between winners and losers (r5 0.10). In parti-cular, the vote for the 1982 winners was underestimated despite their higher levels of recalland recognition. In addition, the unusual underestimate of the vote for the Democratic incum-bents who lost in 1994 is not accompanied by atypical voters’ perceptions in this class ofcontests; the winning challengers’ recall and recognition deficits amounted to about 8% and2%, respectively.

In summary, studies of voting behavior in House elections and the analysis of the size andsources of the incumbency advantage must recognize and deal with respondents’ misreportsof their preferences. Regrettably, the search for a satisfactory explanation of respondent biasin recent surveys of House voters remains elusive. In light of its persistence, and the importanceof the phenomena it affects, renewed efforts should be directed toward the solution of thispuzzle. Barring a return to the old question format, the call for the 1998 NES Pilot Study,soliciting scholars’ recommendations to correct the inflated support for congressional incum-bents, offers a new opportunity to improve existing survey instruments, and define a moreaccurate image of voters’ choice in House elections.

Acknowledgements

I wish to thank John Howes and the anonymous reviewers for their comments and suggestions.

Notes

1. On the 1978 NES see, in particular, Mann and Wolfinger (1980).2. For a methodological critique of Cover’s approach see Eubank (1985).3. Before 1978, the NES vote question read as follows: “How about the election for congressman —

that is, for the House of Representatives in Washington. Did you vote for a candidate for Congress?(If yes) Who did you vote for? (If respondent does not know candidate’s name) Which party isthat?” After 1978, respondents were shown a ballot card and asked the following questions: “Hereis a list of candidates for the major races in this district. How about the election for the House ofRepresentatives in Washington? Did you vote for a candidate for the U.S. House of Representatives?

459Franco Mattei

(If yes) Who did you vote for?” In surveys taken between 1956 and 1976, the average level ofovverreporting of the vote for incumbents was about 2%. For an analysis of the effects caused bythe change of format, cf. Jacobson and Rivers (1993) and Box-Steffensmeier and Jacobson (1995).

4. It is assumed that the match between survey and aggregate results refers to the level of support forwinning and losing candidates. This assumption is called into question by our analysis of the 1982data. Survey results about thepartisandivision of the vote in open seats match the aggregate results;reported preferences for districtwinners, however, do not match the observed outcome.

5. The quote, originally from Alexis de Tocqueville, is reproduced and repeated several times in Noelle-Neumann (1993).

6. Gronke (1992) did not find severe overreporting benefitting House winners in the 1988 NES, butthe result appears to be due to his inclusion of uncontested races (Wright, 1992).

7. Like Eubank and Gow, Wright found that the bias is not attributable to nonvalidated voters. Abra-mowitz (1981) hypothesized that some overreporting in the 1978 NES could be due to nonvoters’declared preference for incumbents.

8. Like in previous years (except 1984), respondents were still asked before the vote section whetherthey knew if either of the candidates — whose names were mentioned by the interviewer — “wasalready in the U.S. House of Representatives before the election.” Respondents were also askedwhether they recalled the name and the party of the candidates competing in the district, and what —if anything — they liked or disliked about them. In 1996, the incumbency and recall questions tookplace during both the pre- and post-election interviews.

9. A similar post-election bandwagon effect was discussed by Kelley and Mirer in their analysis of thepresidential vote: “Voters may forget how they have voted; having done so,... they later ’remember,’if asked, having voted for the winner.” (1974, p. 585)

10. All these figures are already purged of uncontested races and other coding errors.11. In this table, percentages are based on the total number of actual votes and reported preferences;

they are not averages of district-level percentages. Given different turnout rates, use of the meanpercentage of the district vote would increase the share of preferences received at the polls by Demo-cratic candidates.

12. Not surprisingly, these results are related to the resources of a challenger’s campaign. In 1982, themedian expenditure of challengers in the sample exceed that of the excluded challengers; in 1988,the median expenditure of NES challengers was less than 40% of the median expenditure of non-NES challengers.

13. This is the case in 1990 and 1992. Choice of different baselines may affect both the size and thedirection of the partisan bias; see, for instance, 1982 and 1984.

14. The incumbency advantage is estimated according to the model outlined in Gelman and King (1990);its average value for the 1984, 1986, 1988, 1990, 1994 and 1996 elections is about 10%.

15. Throughout the 8-election period, only 244 of 6109 respondents, or 4%, reportedly cast a vote inraces lost by incumbents; this percentage was highest in 1994 and lowest in 1986. The discrepancybetween declared and expected preferences mentioned in the text is based on the pool of all respon-dents and thus takes into account different sample size.

16. In 1982, the result is largely determined by the gross underestimate of the support for one Democraticwinner (Jim Cooper who defeated Cissy Baker in TN04 — the latter, daughter of Senate majorityleader Howard Baker, probably enjoyed a name recognition advantage), and one Republican winner(John McKernan who beat John Kerry in ME01). Because of the low number of cases, modestchanges in reported preferences would eliminate seemingly large discrepancies. A shift of 12 respon-dents’ votes would erase the 13.3-point difference. In 1990, both pro-Republican and pro-winnererrors would almost entirely disappear by excluding the results for the contest in NH01. Support forthe winner, Bill Zeliff, is overreported, and respondents in the district account for 28% of all votes.In other years, however, a party’s advantage is spread across most races. In 1984, preferences forRepublican candidates were overreported in 8 of the 9 congressional districts, producing the onlyoccurrence of a larger bias for winners of open seats than for incumbents. In 1996, preferences forDemocratic candidates were overreported in 15 of the 17 districts with more than one respondent.

17. These figures, unlike the averages shown in the last column of Table 2, make allowance for differentsample size. Exclusion of the 1982 election, the most detrimental to open seat winners, only raisesmean overreporting from 0.3% to 1.7%, (it remains at 9.1% in incumbent-held districts).

18. The original model also included a dummy variable for party; since its effect was not significant,


the variable was dropped from the final equations. Estimation by weighted least squares producessimilar results, and the outcome of the analysis is not changed by inclusion oflosing incumbents.Finally, the regression for the subset of competitive open races (n5 859) replicates the estimatesshown in the first column of the table.

19. Time of interview and an interaction term (time of interview*actual district vote) were added to theexpected vote in an equation predicting reported vote. Their effects, however, were very weak andstatistically insignificant.

20. In the first week after election day, the vote for winning incumbents wasoverreportedby 7.8% whilethe vote for candidates winning open seats wasunderreportedby 4.5%.

21. Recognition of a candidate is based on the respondents’ ability or willingness to rate that candidateon the 0–100 thermometer scale.

22. As anticipated, the value of the coefficients is sensitive to specific elections. The recall coefficientsbased on seven observations (excluding one election at a time) range from 0.87 to 0.58 in Democraticdistricts, and from 0.21 to2 0.25 in Republican districts; the recognition coefficients range from0.75 to2 0.10, and from 0.51 to2 0.04, respectively.

References

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Asher, Herbert (1995)Polling and the Public. CQ Press, Washington.Box-Steffensmeier, Janet M. and Jacobson Gary C. (1995) Question Wording and the House Vote: Some

Experimental Evidence. Paper presented at the Annual Meeting of the Southern Political ScienceAssociation, 1–4 November, Tampa, Florida.

Cover, A. D. (1977) One good term deserves another: the advantage of incumbency in congressionalelections.American Journal of Political Science21, 523–541.

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winning at the polls and in the polls: the incumbency advantage in surveys of u.s. house voters

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