Jury Study

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THOMAS L. BRUNELL,CHETAN DAVE,NICHOLAS C. MORGAN1University of Texas at Dallas; University of Texas at Dallas; Collin College

We examine the time it takes to reach a verdict (deliberation time) using a unique dataset on thedeliberation times of actual juries in criminal and civil cases. Duration model results indicate that casecomplexity, the unanimity of verdicts and the process of voir dire affect deliberation times, whereas jurysize, prior juror experience and the gender composition of juries are not significant correlates. Theresults shed empirical light on an important correlate of trial accuracy using real-world data, in contrastto previous research that employed mock jury data.

1. INTRODUCTION

The American jury system is firmly rooted in the Bill of Rights in the U.S.

Constitution. The sixth amendment states that those accused of a crime by thestate are to have a public and speedy trial heard by a local jury. 2 When viewedthrough an economic lens, the objective behind such a jury-based judicial systemis to resolve a dispute by a group of peers engaging in collective decision-making.If juries actually achieve this objective, there are two dependent variables ofinterest. The first is the actual verdict agreed upon by a jury, that is, the outcomeofthe collective decision-making process. The second variable is the process by

which a jury reaches a verdict, theprocessof collective decision-making itself. Onespecific aspect of the deliberation process is the time that it takes for a jury toreach a decision this is the focus of our analysis in this paper. Specifically, we

1 We would like to thank Patrick Brandt, Valerie Hans, Magnus Lofstrom, and the anonymous

reviewers for this journal for helpful comments.2 Specifically, the sixth amendment stipulates that In all criminal prosecutions, the accused

shall enjoy the right to a speedy and public trial, by an impartial jury of the State and districtwherein the crime shall have been committed.


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are interested in the length of time taken by real-world juries to render a verdict;and the determinants of the time to verdict as a function of the characteristicsof the case at hand and the socio-demographic composition of the jury. Incontrast to previous research that has focused on mock juries, we examine a richdataset on 32 jury panels with over 6,000 jurors who served on over 1,000 trials.

The dataset contains a number of case-specific and juror-specific variables inaddition to the time it takes a jury to render a verdict.Why are we interested in this aspect of the process of collective decision-

making in legal environments?3 Our answer is that shining the empiricalspotlight on deliberation times can affect judicial economy considerations,provide further insight into the more social sciences aspects of the law, andhelp further our understanding of the jury system beyond that which we find

with mock juries. The judicial branch of government has an interest inefficiently marshaling the scarce resources allocated to it by the legislative andexecutive branches. Once a case has been accepted to be heard by the court,the judicial system has an interest in disposing of the cases in a timely mannersince each judge typically oversees a limited number of trials at any given time.

Additionally, the court is concerned about the system costs imposed on trialparticipants, in particular the jurors. For instance, the foregone earnings ofjurors may be considerable, e.g. low-income jurors who may not getcompensated from their employer for their service may suffer a cost higherthan high income jurors who do get compensated.

Finally and crucially, an important motivation for studying deliberation timesis the quality of verdicts themselves (trial accuracy). While deliberation timemay be costly, it also has benefits in terms of improving the quality of the

verdicts that a jury renders. A jury that is biased against (or in favor of) thedefendant is likely to make less effort to process information produced at trialand jump more quickly to judgment. Hence, deliberation time may be a usefulsignal of jury bias. Viewed in this light, several of the results of our analyseshave interesting welfare implications. For example, our result that deliberationtime is longer if the number of jurors dismissed during jury selection is greatersuggests jury selection might be effective at reducing jury bias. Indeed, duringthe jury selection stage, lawyers have the opportunity to select juries tominimize the biases against their clients.4 In summary, we are interested in

3 See Mialon and Rubin (2008), Mialon and Mialon (2008), and Mialon (2005) for examples ofthe analysis of judicial environments from an economic/econometric perspective.

4 For a theoretical examination of the link between jury selection and jury bias, see Neilson andWinter (2000).

556 / REVIEW OF LAW AND ECONOMICS 5:1, 2009

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informing such judicial economy by analyzing the determinants of how long ittakes a jury to reach a verdict.5

From an empirical legal point of view, much has been written on the subjectof individual juror perception of evidence as presented during trial, jurorcomprehension of the evidence, and the individual processing of information.6

The process of deliberation has also undergone scrutiny with several models ofdecision-making presented.7 Much of this research has been conducted usingmock juries. Since mock juries typically have built-in time constraints, theycannot be used as a measurement of actual jury time to a decision point. Devineet al. (2007) discuss another important aspect of deliberations, the notion ofdeliberation quality and its concomitant effect on verdicts. Our analysiscomplements these previous empirical legal findings. Further, Devine et al. (2007)

provide compelling arguments and evidence in favor of analyzing actual versusmock juries. In the present analysis, data from actual juries are examined,mitigating the causal inference issues present in analyzing mock juries. Our mainresults suggest that 6-person juries are no quicker than 12-person juries; as casesbecome more complex and/or more severe, juries deliberate longer; non-unanimous decisions take longer to reach than unanimous ones and panels thatsaw many potential jurors excused during voir dire end up deliberating longerthan panels with fewer challenges.The remainder of this paper is structured as follows. Section 2 provides a

literature review that motivates in detail the various process questions that canbe asked of the data. In Section 3 the data are discussed followed by adiscussion of the empirical hypotheses. In Section 4 the empirical results arepresented and discussed, followed in Section 5 with concluding comments.

2. MOTIVATING LITERATURE

Given the difficulty of gathering data on or observing real juries, legal scholarsoften rely on mock juries to better understand jury behavior and the process by

which they reach (or fail to reach) a collective decision. Clearly, using actualjuries provides the most appropriate source of research information becausejury simulations cannot fully enact important variables or environmentalfeatures found in actual trials decided by real juries (Diamond and Rose, 2005).More specifically with respect to the variable of interest in this paper,

5 Critics of the jury system contend that trial by jury is a costly relic, consuming vast human

resources and government expenditures, see Kassin and Wrightsman (1988) and Hans andVidmar (2001).

6 See for example, Ellsworth (1989) and Strodtbeck et al. (1957).7 See Winship (2000).

Factors Affecting the Length of Time a Jury Deliberates / 557

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measuring deliberation time in experimental settings has proven to beproblematic, typically due to time limitations. Ellsworth (1989) conducted 18mock juries using the same information stimulus and none of the 18 were ableto come to agreement within the one-hour limit.

Saks and Marti (1997) reviewed eleven studies that report length of deliberations;however, only two reported significant test statistics. They report a meandifference in deliberation time to be 20 minutes for 12-person juries compared to6-person juries. For the three studies examining actual juries, a mean differenceof 44 minutes is noted. They conclude that the small time savings that comefrom reducing the size of juries would provide slight justification for any losses inrepresentation and quality of deliberation. Beiser and Varrin (1975) found thatlarger juries, in addition to awarding larger damages on average relative to smaller

juries, were also more likely to deliberate for longer stretches of time. Not allstudies found that smaller juries deliberate for shorter periods of time Kessler(1973) showed that smaller juries had greater participation rates among jurors andtended to deliberate for longer periods of time. Nemeth (1977) found that theunanimity requirement, not surprisingly, leads to more hung juries and longerperiods of deliberation. Saks (1977) found that neither jury size nor decision ruleaffected the length of time that a jury spends on deliberations.

Katzev and Wishart (1985) examined the impact of two important factors onlength of deliberations. First, they found that when a judge summarizes theevidence for the jury, this significantly reduces the time to reach a conclusion.Moreover, when the judge included remarks about the fallibility of eyewitnesstestimony in addition to the evidence summary, juries took significantly lesstime still to deliberate. So, to the extent that jury instructions can add clarity tohow juries ought to weigh some evidence, deliberation time can be lessened.Maass et al. (1985) demonstrate that expert testimony in a trial tends to lead tolonger deliberations than without; this is especially true when the expert didnot provide a causal explanation.

Kerr (1982) finds that systematic polling of the jury tended to decrease thelength of time that the jury took to come to a conclusion, although Davis et al.(1993) find that when juries are mandated to take a poll, they tend to hang moreoften and take longer to deliberate.

Unanimous jury verdicts were accepted as a basic function of the jury systemfor over 600 years (Abramson, 1994). In 1972, the Supreme Court decided in

Apodaca v. Oregon8 and Johnson v. Louisiana9 that unanimous verdicts were nolonger required in non-capital state cases. As a result, states have been freed to

8Apodaca v. Oregon, 406 U.S. 404 (1972).9Johnson v. Louisiana, 406 U.S. 356 (1972).




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permit non-unanimous verdicts. In criminal felony trials, the jury verdict mustbe unanimous at the federal level and in all states except for Louisiana andOregon, while in civil trials the federal requirement is the same but only 18states require unanimous outcomes.10

Given this brief review of the legal literature, and prior to discussing the data,we note that the best research design would have both a 6- and 12-member jurydecide the same case simultaneously. We have to settle for the second best ofcomparing juries of different sizes deciding somewhat similar cases. As wediscuss below though, the severity of the crime is related to the size of the jury,

with the most severe crimes (i.e., murder) all being heard by 12-person juries.

3. THE DATA

A recurring challenge in jury deliberation analysis is the difficulty in obtainingdata. Most of the data on juries comes from experimental situations which bytheir very nature constrain the length of time deliberations may take place.Other studies of actual juries tend to be limited in scope and scale. However,there is a source of data that has not yet been systematically examined theMultnomah County [Oregon] Jury Project (Grofman, 1979). The records wereobtained from the Fourth Circuit Court, Multnomah County (Portland)Oregon during the period 1973-1976. The database contains 32 jury panels

with 199 variables covering 6,657 jurors and 1,159 trials.11

The data include both individual-level juror and aggregate jury caseinformation. The information collected in the trial summaries includeidentifiers for members of the particular jury, their votes, the final verdict, the

type of case, and the amount of time taken by the jury to arrive at a decision.Each monthly juror panel recorded the jurors age, occupation and years inresidence in Oregon. Each juror also completed a self-administereddemographic data sheet which collected the jurors educational background,spouse and children summary and any past jury or trial experience.

While jury duty today in Oregon is restricted to a single day (excepting of courseif one is picked to serve on a panel and the trial or deliberations last longer), in the1970s jurors were called for an entire month. As Grofman and Feld (1976) note:

During that month of service, members of the jury pool may sit on asmany as ten different cases. Some 190-220 jurors serve each month,

with a case load of 40-60 trials in Circuit Court (primarily twelve-

10 See Diamond et al. (2006).11 These data are available from the ICPSR (Inter-university Consortium for Political and Social

Research, Ann Arbor, MI).



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member juries). No special effort is made in Multnomah County toprevent jurors from serving together more than once during their monthof service and repeated dyads, triads, and even tetrads and occasionalhigher order groupings do occur. In drawing up jury panels inMultnomah County, court officials do, however, attempt to equalizeactual jury duty by giving priority on panel placement to those membersof the jury who were removed on challenges or who were participants incases dismissed or resolved out of court after the jury has been selectedbut before it has had a chance to meet.

The selection of Multnomah County was fortuitous beyond the fact thatjurors did serve on multiple panels over the course of the month, because there

were other interesting features of jury service and state law in Portland,

Oregon, at the time that allow us to test other hypotheses. For instance, thecounty utilized both 6- and 12-person juries and Oregon law allows for non-unanimous jury decisions (with the exception of capital murder cases). For thispaper the most important feature of the dataset is that, for virtually every trial,the time that the jury began deliberating was noted, as well as the time that thejury finished deliberating. Rarely has any extensive data been collected in actualcourt proceedings which examines the difference in how long juries ofdifferent composition take to deliberate.

There are 203 6-person jury trials and 931 12-person trials. Half of the 6-personcases are criminal trials and half are civil trials. Most of the criminal trials heardby these smaller juries are for lesser crimes like drunk driving. Sixty percent of12-person trials in the dataset are civil trials and forty percent are criminal. These

criminal trials do, however, include the more serious crimes like murder andrape. Slightly more than half the jurors are female and the average age is 47.Among criminal trials, the juries in this sample found nearly three-quarters of thedefendants guilty, while on the civil side just over half of the cases ended with afinding of liability. The wide range of types of cases leads us to classify casesrather broadly (criminal v. civil, crimes against persons v. property crimes, etc.).

The average jury in our data deliberates for 114 minutes prior to reaching adecision. The quickest jury managed to come to a conclusion after just 11minutes and the longest deliberation in our data was 470 minutes.

The primary data of interest for this analysis is the time taken by the ith jury

for deliberation, denoted as i in this paper. The time element was coded witha start hour/minute and stop hour/minute. As the panel method of jury

procurement was used in Oregon at the time of the research, individual jurorscould sit on multiple juries. Therefore, analysis of an individuals juror time ofdeliberation over a series of trials may be studied.




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First, we want to investigate whether civil and criminal cases differsignificantly in the length of time it takes for a jury to reach a decision. We donot have any theoretical expectations regarding potential differences indeliberation time, but since some of our independent variables differ betweenthese two kinds of cases, there are already reasons to model them separately.Looking at Figure 1 it is clear that early on, during the first 100 minutes, thereis no significant difference between the two types of trials, although civil casesended slightly less quickly than criminal ones. After 100 minutes the two linescross, and then at around 300 minutes a large gap between the two develops.

This indicates that after a jury has deliberated for around 5 hours theconditional probability of a civil trial jury finishing at that point is much greaterthan the conditional probability of a criminal trial jury to reach a verdict. Dueto these differences and the fact that we do have different variables forcriminal and civil trials, we model these two kinds of trials separately.

Next, we take up the issue of jury size and how this impacts deliberation time.We hypothesized that the smaller the jury the more rapidly they would come toa decision. Getting 5 of 6 people to agree on something is, ceteris paribus, easierto do than getting 10 of 12 to agree. The data support this hypothesis. Theaverage length of time in a 6-person jury case is only 81.5 minutes (standarderror is 4.46), while a 12-person jury takes, on average, just over two hours toreach a conclusion (121.5 minutes, with a standard error of 3.01). A t-testconfirms that this difference is statistically significant at all conventional levels.Moreover, looking at Figure 2, it is plain to see that 6-person juries are a) muchmore likely to end quickly, and b) do not even have any observations past 400minutes of deliberation time.

Next we take up the issue of case complexity. We theorize that as thecomplexity of a case increases, the jury will tend to take longer to make adecision since there is more to consider in the jury room. For our purposes, wemeasure the complexity of a case in a criminal trial as the number of countsbrought against the defendant. For civil trials we use whether or not the jurydecided to award damages. Figure 3 demonstrates that indeed when a jury hasto consider multiple charges rather than just a single charge, the jury tends totake longer to deliberate. The single count juries are far more at risk of endingrelative to multiple count juries.



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Figure 1: Hazard Rates for the Length of Jury Deliberationin Criminal and Civil Trials

.0

05

.01

.015

.02

.025

0 100 200 300 400 500Time to Decision

Civil Criminal

Smoothed Hazard Estimates

Figure 2: Hazard Rates for the Length of Jury Deliberation

for 6- and 12-Person Juries

0

.01

.02

.03

0 100 200 300 400 500Time to Decision

Six Person Jury Twelve Person Jury





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Figure 3: Hazard Rates for the Length of Jury Deliberationfor 1 and Multiple Count Cases

0

.005

.01

.015

.02

0 100 200 300 400 500Time to Decis ion

One Count Multiple Counts



for Small versus Big Damages Cases

0

.01

.02

.0

3

0 100 200 300 400Time to Decision

Small Damages Big Damages




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In Figure 4, we similarly see that juries for civil trials that award damages areless at risk of ending relative to juries that end up not awarding damages. Thelines do cross at around the 300-minute mark, this means that if a jury whichends up awarding no damages deliberates for more than 5 hours, they tend totake more time to deliberate than juries that do end up awarding damages.

In criminal trials, juries that are considering charges having to do with crimesagainst a person (murder, rape, assault) will end up deliberating longer onaverage than a jury considering other, less severe, criminal charges (robbery,fraud, illicit card games, etc.). A comparison of means test shows that crimesagainst persons do result in long jury deliberation times relative to crimesagainst property. The average time for a jury considering more severe chargesis 136.3 minutes (7.7 standard error) and the average length of time for less

severe charges is 109.9 minutes (2.74 standard error). This difference issignificant at the .001 level. Figure 5 also shows that crimes against personsgenerate significantly lower hazard rates than crimes against property,indicating they are less at risk of ending more quickly.


in Crimes against Persons and Property

0

.005

.01

.015

.02

0 100 200 300 400 500Time to Decision

Other Person





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Figure 6: Hazard Rates for the Length of Jury Deliberationfor Unanimous and Non-Unanimous Decisions

0

.01

.02

.03

0 100 200 300 400 500Time to Decision

Non-unanimous Unanimous


Next we turn to the issue of unanimous versus non-unanimous jury verdicts. Asdiscussed above, Oregon has a 10 of 12 rule where, with the exception of acapital crime, a defendant may be convicted or exonerated with just 10 of the 12jurors in agreement. Since there is no reason for juries to achieve unanimity, thisought to result in relatively quick deliberations for unanimous juries and longerones for non-unanimous juries. The logic here is that if there is a vote among thejurors and it is split with less than 10 on one side or the other, the jury willcontinue to deliberate and, most juries will eventually end up with a decision and

with the most likely split being 10-2. Whereas a jury in Oregon that is split 10-2 or11-1 does not need to continue to work to achieve unanimity. The averageunanimous decision takes 90.6 minutes (standard error is 3.6) and the averagenon-unanimous jury takes 132.5 minutes (standard error is 3.6). The differencebetween these two means is significant at all standard levels of significance. Figure6 shows that there is a more interesting story to tell, inasmuch as early on in thedeliberative process unanimous juries are more likely to reach a verdict quickly,but at just past 200 minutes the two lines cross. So after a jury has beendeliberating for some time, the hazard ratio for a jury that is non-unanimous ishigher than that for a unanimous one. This difference could be an artifact of the

unanimity requirement of capital crimes cases in Oregon. The multivariatemodels, presented below, will help us understand this dynamic better.



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jurors about the innocence or guilt of the defendant, thereby speeding up thedecision-making process.15 Those cases that involve crimes against personssystematically take longer to reach verdicts relative to other, less severe, crimes.

As in the graph described earlier, as a jury considers multiple counts against adefendant, the group takes longer to reach a decision. The use of preemptorychallenges signals, we theorize, a more contentious trial. So we expect thecoefficient to be less than 1 and it is in our model. So, as the number ofexcused jurors increases, so does the length of time the final jury deliberates.

The causal mechanism for this relationship is not direct. We believe that thehigh number of challenges is merely an indication of a tough and divisive trialahead, with well-prepared attorneys on both sides. These kinds of trials arelikely to lead to more time in the jury room.

Next we examine the effect of prior jury service on the ability of a jury to cometo a relatively quick conclusion. The hazard ratio for the prior jury servicevariable is 2.84, indicating that as the number of jurors with prior jury serviceexperience increases, the jury reaches a decision more quickly. The p-value is .089in a two-tailed test, just outside the bounds of traditional levels of significance.Finally, we test the effects of gender dominance on jury deliberation time. Wemeasured the variable in terms of the proportion of the jury membership that

was male, and the variable is not significant and the coefficient is just slightly lessthan 1. We can conclude that gender composition of the jury does not have asignificant impact on the length of jury deliberations.

As mentioned above, civil and criminal trials are modeled separately, so now weturn to the inferential model of deliberation time for civil trials. The results ofthese analyses are presented in Table 3. In this model, the hazard rate for the size

of the jury is less than 1, but not statistically significant. Unanimous decisionstake significantly less time to reach than non-unanimous decisions, as wehypothesized. The previous two results more or less matched the results in thecriminal model. The guilty variable however is different in civil trials insofar asthe verdict finds the defendant either liable or not liable and a person's freedomis not at stake, but this is more a resolution of a dispute between two parties. Theguilty variable hazard was greater than 1 in criminal trials, which was unexpected.In civil trials however, juries that find against the defendant do take longer thanthose that find for the defendant. Prior jury service had the effect of speeding updeliberation for criminal trials, but that is not the case in civil trials. There is nodiscernible difference in time to a decision with experienced jurors on the panel.

15 Ideally we would like to have a variable that is indicative of case quality; however, the datasetdoes not allow the construction of such a variable. We expect therefore that allowing forunobserved heterogeneity across cases controls for this effect.



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Juries with more male jurors are indistinguishable from juries with fewer malejurors. Finally, the case complexity variable, damages awarded for civil trials,works as expected. The higher the damages awarded, the longer the jury took, onaverage to come to a conclusion. In terms of model fit for both models, we notethe following. First our assumption of the underlying Weibull distributiondescribing the duration data is appropriate given that for both models theestimated measure of curvature of the distribution (p) is positive and significant.

Second, for both models, the estimate of is significant and different from zero,indicating the presence of unobserved heterogeneity.16 Third, Figures 7 and 8below show the Cox-Snell residuals from the two multivariate models forcriminal and civil cases respectively.

When the residual plot is near the 45-degree line, this indicates a good fit for the

model. Finally, the chi-squared statistics for both models indicate that the variablesincluded are jointly significant at 5%. This is suggestive of a good model fit.

Table 3. Factors Affecting Jury Deliberation Time in Civil Trials

Variable Hazard Ratio |p|-value

Size of Jury 0.7222 0.117(0 = 6, 1 = 12)

Unanimous Decision 1.6760 0.001(0 = No, 1 = Yes)

Defendant Found Liable 0.5667 0.000(0 = Not liable, 1 = Liable)

Damages 0.9957 0.000(Continuous variable in thousands of dollars)

Prior Jury Service 0.6340 0.358(Proportion of jurors with jury experience)

Number Excused 0.9178 0.002(Number of jurors dismissed during voir dire)

Proportion Male 0.9382 0.596(Proportion of male jurors)

Std. Err.

P 1.93 0.107

0.3657 0.077

Obs. 657

Clusters (Judges) 22

logL 706.88

16 This parameter characterizes unobserved heterogeneity in the parametric forms of the hazardfunctions.




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Figure 7: Cox-Snell Residuals for Criminal Trials

Figure 8: Cox-Snell Residuals for Civil Trials

0

2

4

6

8

0 2 4 6 8Cox-Snell residual

H Cox-Snell residual

Cox-Snell Residuals-Criminal

0

2

4

6

8

0 2 4 6Cox-Snell residual

H2 Cox-Snell residual

Cox-Snell Residuals-Civil



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4.2.ROBUSTNESSGiven the results reported regarding jury size in Tables 2 and 3, it is instructive todiscuss estimation results by breaking down our models using both thecivil/criminal dichotomy and a 6-person jury/12-person jury dichotomy. Table 4below presents the estimation results for criminal trials for both 6- and 12-personjuries. Relative to Table 2, it is clear that regardless of jury size unanimous verdicts

were reached faster (as were guilty verdicts), but only for the larger-sized juries,since the estimated hazard ratio for guilty verdicts in 6-person juries has a largestandard error. Overall, the pattern of results is similar to those reported in Table 2,albeit some of the statistical significance of the estimates is weaker in the 6-personjury data. This may well be due to the possibility, as indicated in Table 1 above,that 6-person juries were employed in less severe crimes, but it may also be the

case that the smaller sample size for 6-person juries is a contributing factor.

Table 4. Criminal Trials by Jury Size

6-person Juries 12-person Juries

VariableHazardRatio

|p|-valueHazardRatio

|p|-value

Unanimous Decision 2.66 0.063 2.176 0.000(0 = No, 1 = Yes)

Guilty Verdict 0.674 0.18 1.364 0.000(0 = Innocent, 1 = Guilty)

Crime Against Person 1.325 0.282 0.656 .011

(0 = No, 1 = Yes)Number of Counts 0.546 0.059 0.681 0.000(Number of counts considered by jury)

Prior Jury Service 2.129 0.236 3.033 .037(Proportion of jurors with jury experience)

Number Excused 0.906 0.168 0.907 0.000(# of jurors dismissed during voir dire)

Proportion Male 1.57 0.197 0.863 0.112(Proportion of male jurors)

Std. Err. Std. Err.

P 2.03 0.75 1.583 0.179

0.7188 0.181 0.185 0.149

Obs. 102 371

Clusters (Judges) 14 18

logL -120.15 -441.81




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Table 5. Civil Trials by Jury Size

6-person Juries 12-person Juries

VariableHazardRatio

|p|-valueHazardRatio

|p|-value

Unanimous Decision 2.21 0.076 1.652 0.000(0 = No, 1 = Yes)

Defendant Found Liable 0.635 0.10 0.569 0.000(0 = Not liable, 1 = Liable)

Damages 0.976 0.001 0.996 0.000(Continuous variable in thousands of dollars)

Prior Jury Service 0.223 .037 0.816 0.356(Proportion of jurors with jury experience)

Number Excused 0.925 .186 0.918 0.002(Number of jurors dismissed during voir dire)

Proportion Male 1.034 0.43 0.915 0.25(Proportion of male jurors)

Std. Err. Std. Err.

P 2.386 0.325 1.86 0.144

0.752 0.274 0.293 0.121

Obs. 101 371

Clusters (Judges) 15 22

logL -104.07 -599.91

Next, Table 5 below presents the results for civil trials broken out by jury size.Again, the pattern of results is similar to those reported in Table 3 for the

entire sample. Like the breakdown for criminal trials, the significance of theestimates when only using 6-person jury data is a bit weaker; however, thosevariates that were of weak significance before continue to be indistinguishablefrom zero (e.g., Proportion Male). In summary, Tables 4 and 5 suggest that theinsignificance of jury size on determining the speed with which case verdictsare made continues, since regardless of jury size, in either civil or criminal trials,our main results tend to hold.

5. CONCLUSION

After being presented with the evidence in court, the jury retires to the juryroom to begin deliberations. What happens inside this room is both importantand interesting, not only to the participants, but to many scholars as well. What

factors affect how a jury goes about its business? Does the size of a jurymatter? How about the composition? In this paper, we have taken a first lookat one aspect of this collective decision-making process the factors that affect



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the length of time a jury takes to come to a decision. The results we presentcan therefore be viewed as stylized facts that do not arise from an analysis ofmock jury data but data on actual juries.

While there appears to be a big difference in time between 6- and 12-personjuries when simply comparing how long it takes each to come to a verdict, in themultivariate models the difference between the two was not significant. Thismight be because none of the 6-person juries deliberated longer than 379minutes, while 12-member juries maxed out in our dataset at nearly 500 minutes.So, after controlling for the other factors, e.g. severity of the crime or casecomplexity, these differences disappear. Unanimous decisions are much quickerthan non-unanimous decisions, although we attribute these differences to thestructural rules that govern jury decision-making in Oregon. Since Oregon allows

less-than-unanimous decisions, this means that unanimous juries are almostcertainly panels that start out unanimous from the outset of deliberations. Astrong indication that a jury may take longer than average is the number ofpotential jurors who are excused during the jury selection process. We take this tomean that the use of many preemptory challenges (or for-cause challenges) maybe a leading indicator of a contentious trial. It could also be the case that thepotential leaders in the jury pool are removed with these challenges and the jury isleft with few or no people that might lead them to a quick and (hopefully)accurate decision. The one stark difference between criminal and civil juries is that

when a jury comes back with a conviction in a criminal trial, it is typically muchquicker than for juries that acquit. On the civil side, finding the defendant liabletakes longer than exonerating him or her. The analyses reported here havebrought further insight into the dynamics of jury deliberation. We should note

that there is a link between the length of time that juries deliberate and theaccuracy of the verdicts. Devine et al. (2001) and Hastie et al. (1983) find that thelonger a jury deliberates the more likely they are to reach an accurate decision. So

we are not arguing that the government ought to be purposefully looking formethods to speed up jury deliberations, since this approach could affect theaccuracy of verdicts. Future research could include more case-specific data like thenumber and types of witness, a measure of the quality of the evidence, and therace and ethnicity of the defendant and the jurors themselves. Future research

would also, given our stylized facts, develop appropriate structural models ofhazards that is, develop tightly linked optimization hypotheses to explain a jurystime to decision, accounting for the findings presented in this paper.




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