Article

The Impact of Joinder and Severance on Federal Criminal Cases: An Empirical Study

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Abstract

It is widely assumed that criminal defendants who face multiple charges in a single trial have a harder time prevailing than those who face several trials of one count each. Conventional wisdom also has it that a defendant who is joined for trial with other suspects is worse off than one who stands trial alone. Until now, these assumptions have never been tested empirically. Looking at nearly 20,000 federal criminal trials over a five-year period, this Article asks if the traditional beliefs are true, and if so, tries to measure the impact on trial outcomes of joining counts and defendants. It turns out that joinder has a significant prejudicial effect on trials, although not quite the same effect that is usually assumed. Using statistical models that control for a range. of variables, the authors discovered that trial defendants who face multiple counts are roughly 10% more likely to be convicted of the most serious charge than a defendant who stands trial on a single count. Surprisingly, however, joining co-defendants in a single trial had virtually no impact on the likelihood of conviction, at least in the aggregate. Using the results of the empirical study, the Article then reconsiders the competing policy issues that underlie the joinder and severance doctrine, and explores the implications of the findings.

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... Courts have seemingly adopted a broad conception of this criterion (United States v. Woody, 1995). In fact, the current policy does not explicitly require that defendants who are tried together be suspected of colluding to commit the crime(s), or that they have even met one another (Leipold & Abbasi, 2006). ...
... As one court concluded, "Thus, in evaluating joinder under rule 8(b), the trial court must balance its obligation to avoid prejudice that may result from joining multiple defendants against a policy favoring maximum trial efficiency" (United States v. Bledsoe, 1982, p. 4). Given the propensity of judges toward judicial efficiency, it is unsurprising that the bar for severance is set high; for it to be granted, defendants must demonstrate prejudice that is substantial, severe, or compelling (Leipold & Abbasi, 2006). ...
... Of the over 375,000 federal defendants processed between the fiscal years of 1999 to 2003 (the last period for which data is publicly available), roughly one-third were adjudicated with at least two defendants; 24% involved more than two defendants and 14% involved five or more defendants (Leipold & Abbasi, 2006). Further, no published research has demonstrated that trying criminal defendants together produces significant or systematic biases, although many (including judges) believe they exist (Dawson, 1979;Farrin, 1989). ...
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Suspects accused of involvement in the same crime can be tried in one multiple-defendant trial. While research has long demonstrated the difficulties of being a juror, no published work has examined whether multiple-defendant trials compound these difficulties. The current research recruited both student and community samples to determine whether trying multiple defendants would increase conviction rates for individual defendants. Every participant watched one of three trial videos—a single defendant against whom the State had a strong case (single-strong), a single defendant against whom the State had a weak case (single-weak), or a multiple-defendant trial combining both defendants (multiple-defendant). The findings demonstrated an overshare effect—when the defendants were tried together, overall conviction rates for both defendants increased relative to when they were tried alone, though the pattern of results differed by study sample. Although we are unable to provide a definitive mechanism underlying the results, the best explanation seems to be that multiple-defendant trials prompt jurors to engage in a joint evaluation of the defendants, rather than single evaluations of each. Consequently, participant-jurors’ perceptions of each defendant are impacted by how they compare with one another. Thus, the current research casts some doubt on the fairness of multiple-defendant trials.
... This may have been a strategic decision so as not to jeopardize the case against the defendant in relation to the other, stronger complainants. A defendant is more likely to be convicted when multiple complainants testify against them in the same trial (Goodman-Delahunty & Martschuk, 2020; Leipold & Abbasi, 2006;Martschuk et al., 2024). ...
Article
Background Attrition of child sexual abuse (CSA) cases occurs at different stages of investigation, and only a small proportion of the cases reported to police are referred for prosecution. Different factors have been linked with the prosecution of CSA cases; however, little is known about how prosecutors determine which cases should proceed and which should not. Objectives This paper investigated criteria and thresholds used by prosecuting lawyers in deciding whether a child sexual abuse case should proceed. Participants and Setting Fifty-six Australian prosecution case files (79 complainants; 58 defendants) were reviewed. The cases included contemporaneous and historical allegations of child sexual abuse, ranging from a single incident to repeated, protracted abuse over a decade. Method Written notes and emails in prosecutors’ files were searched for perceptions of the complainants, decisions to proceed and verdicts. Results When a complainant was considered inconsistent in some way, giving rise to recorded concerns about their credibility or reliability, 82.3% of these cases culminated in discontinuance or an acquittal. Conversely, 78% of cases with complainants who were regarded as largely consistent throughout the investigation culminated in a conviction. Recorded issues with a complainant’s memory of the events, cognitive capacity, and confusion about the alleged assault were not associated with case outcomes. Conclusion Most CSA cases that were referred for prosecution resulted in proceeding with charges against the defendant. Perceived issues with the consistency and credibility of the complainants’ evidence were the most important decisional factors.
... The results of our study are consistent with prior research that the existence of co-defendants did not impact the chances of conviction (Leipold and Abbasi, 2006). Despite these aggregate results, intuitively, on a case level, there could be an impact. ...
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Purpose Cryptocurrencies have been used to commit various offences, but enforcement efforts remain underdeveloped relative to the value of these crimes. This paper aims to examine factors associated with outcomes of US-based cryptocurrency financial crime prosecutions. Design/methodology/approach The authors studied the 37 resolved cryptocurrency-based financial crime cases in the USA to date, exploring the impact of offence, defendant and evidence characteristics on the mode of disposition and penalties. The authors used bivariate analyses and logistic regression models to determine relationships among these variables. Findings The presence of individual defendants only (rather than a corporate defendant or combination thereof) and the use of only a cryptocurrency other than Bitcoin in committing a crime each made a case less likely to be resolved by dismissal, trial or summary or default judgement. Originality/value This paper is the first to examine variables contributing to financial crime prosecution outcomes and has implications for prosecutorial decision-making, resource allocation and the prevention and detection of financial offences involving cryptocurrencies.
... Decisions around charging and secondary charges constitute a key point of discretion in sentencing (see, generally, Bowen, 2009). Having multiple charges is a significant and positive predictor of conviction, incarceration rates, and sentence length (Leipold & Abbasi, 2006;Nelson, 2014;Steffensmeier & Demuth, 2006), as these defendants may be seen by court actors as more dangerous (Greene & Loftus, 1985). In Florida, common additional charges include grand theft, resisting arrest, and drug possession. ...
Article
This study examined whether and how discretionary sentencing add-ons (i.e., secondary charges, victim injury points, firearms/weapons points, drug trafficking enhancements) contribute to disparities. We examined add-ons that increase sentencing points and so contribute to a defendant “scoring to prison.” We analyzed: (1) the degree to which add-ons explain racial and ethnic disparities in imprisonment (mediation); and (2) whether add-ons are more adverse for minority defendants (moderation). We did not find that add-ons “explain” racial differences in the use of prison sentences. We did find, however, that some add-ons, particularly those that signal “dangerousness,” are racially/ethnically disparate in their consequences. The findings raise questions about the role of court discretion in perpetuating racial and ethnic disparities.
... Related research examined the impact of charged acts by additional complainants against the same defendant when presented in a joint versus a separate trial. A large-scale archival study (Leipold & Abbasi, 2006) reported a 9% increase in conviction rates in joint over separate trials. Most experimental studies on this topic were conducted in the 1980s. ...
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Internationally, admissible incriminating evidence of uncharged acts by the accused is presumed unfairly prejudicial, and remains 12 controversial. In an experimental study, 325 jury-eligible citizens were randomly assigned to a simulated trial in which the accused faced two 13 charges. Juries were exposed to no evidence of uncharged acts or prejudicial evidence describing four uncharged sexual acts by the accused 14 reported by the complainant or two independent witnesses. Jury inferences about the accused’s sexual interest in children and his criminal 15 intent were logically related to the source and type of evidence. While ratings of the likelihood of culpability increased with evidence of 16 uncharged acts, juries were reluctant to convict solely on the basis of the complainant’s word. Jury deliberations disclosed that prejudicial 17 evidence did not induce impermissible reasoning or a lower threshold of proof. Multiple convergent measures revealed little danger of unfair 18 prejudice to the accused.
... Charging a defendant with more than one crime is correlated to increased rates of conviction. In a study of N = 375,720 federal defendants, Leipold and Abbasi (2006 , Table F) compared, among other things, the conviction rate of individuals facing a single charge and those charged with multiple crimes. The results demonstrated that a defendant's chances of conviction increase by more than 27 percent if multiple charges are filed. ...
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Logistic regression was used to assess five different police actions that an investigating police officer can choose to employ when handling a domestic violence call. Each significantly increases the likelihood the prosecutor will file charges: obtain photographs (60 percent); find and arrest the defendant (94 percent); obtain an emergency protective order (87 percent); locate additional witnesses (68 percent); and list more than one criminal charge in the police report (284 percent). Three optional police actions increase the likelihood of criminal conviction: find and arrest the defendant (78 percent); obtain an emergency protective order (102 percent); list more than one charge (142 percent). Survival analysis shows a sixth action, completing the investigation the same day, to significantly increase rates of criminal case filing and also rates of criminal conviction. A strong case, best practices model for the investigation of domestic violence incidents was validated and is presented. Police discretion is discussed. Lawmakers should consider making these optional investigative actions mandatory.
Chapter
The right to trial by jury granted by the Constitution is one of the cornerstones of American democracy. Jury trials allow the public to participate in the judicial process, which prevents the process from being unfairly used by the government. Without properly understanding the relevant law, jurors are unable to carry out their duties effectively, which can result in unjust outcomes such as innocent defendants being convicted. Judges give jurors instructions to help them understand how to apply the law to the case at hand. The chapter begins by evaluating jurors’ general comprehension of jury instructions, and then presents additional sections on special types of criminal jury instructions, including death penalty instructions, instructions on how to evaluate eyewitness testimony, curative/limiting instructions, joinder instructions, Allen (dynamite) charges, and jury nullification instructions. Each section provides an overview of the law regarding each particular topic, presents the psychological research available on the topic, and provides recommendations on how to apply research findings to improve the effectiveness of the instructions.
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According to law, a defendant may be tried for multiple offenses in a single trial, although the courts intuitively recognize that such "joinder" may be prejudicial. The present study investigated the effects of joinder on jurors' decisions, emphasizing the social psychological mechanisms underlying judgmental biases. 732 representative jurors (aged 18–82 yrs) judged a videotaped trial of a single offense or a joined trial of 3 offenses that varied as a function of (a) charge similarity, (b) evidence similarity, and (c) judges' instructions designed to reduce judgment biases. A defendant was more likely to be convicted on a particular charge in a joined trial than on the same charge tried alone, and judges' instructions were ineffective. Joinder produced confusion of evidence and negative inferences about the defendant, but did not significantly influence perceptions of evidence strength. Defendant and evidence ratings were strongly related to verdicts, whereas confusion was not. Results suggest that the effects of joinder are mediated through inferences about the defendent's criminality. (64 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
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The present research investigated decision-making processes in joined trials of multiple offenses. Subjects judged videotaped trials of three joined charges in a factorial design that varied charge similarity, evidence similarity, and judges' instructions designed to reduce judgement biases; or judged one of several charges presented individually. The results indicated that subjects were more likely to convict a defendant in a joined trial than on the same charge tried by itself, particularly when the charge was presented in the third position. Convictions were more frequent when joined charges were similar, and judges' instructions significantly reduced conviction rates. Subjects judging joined trials confused evidence among charges, rated the prosecution's evidence as stronger, and rated the defendent less favorably than subjects judging single trials. The findings were compared statistically to the results of previous research, and it was concluded that increased convictions in joined trials are robust effects.
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The present study was conducted to determine the process by which jurors reach verdicts in trials in which multiple charges are joined in one indictment. The experiment was designed to test the impact of joinder of affenses, similarity of offenses, and evidentiary strength of jurors' ability to process trial evidence. The results gathered from 220 male and female subjects indicated, as previous research has shown, that joined trials lead to more guilty verdicts than severed trials; that the first charge in a joined trial accounts for this “joinder effect,” receiving significantly more guilty verdicts than its severed counterpart. When joined trials are composed of similar categories of crimes, guilt verdicts increase and jurors tend to confuse evidence-as shown by a high rate of antidefendant intrusions from case two to case one. More antidefendant cognitions were also found when the cases were similar. Furthermore, case similarity interacted with the evidentiary strength of the charges in joined trials.
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What should a court do when a single criminal jury reaches logically irreconcilable verdicts--for example, convicting one defendant of conspiracy but acquitting her sole alleged coconspirator? The Supreme Court has unanimously decreed that a court should do nothing: it should leave the verdicts undisturbed. To reverse the inconsistent conviction would not only require guesswork about what produced the inconsistency, but would also be unfair to the government. The government, after all, might have been the victim of the jury's error, but the Double Jeopardy Clause precludes it from appealing the inconsistent acquittal. To avoid this unfairness, the Court concludes, the defendant must accept her conviction, just as the government must accept the acquittal.In this Article, Professor Muller demonstrates that this do-nothing approach to inconsistent verdicts masks a deep pro-government bias. He argues that the Court has both underestimated the harms that inconsistent verdicts pose to criminal defendants and overstated the impact of such verdicts on the government. He also notes that the Court has imagined only all-or-nothing solutions to the problem of inconsistent verdicts: either reverse all inconsistent convictions, or affirm them all. Professor Muller suggests two solutions that would allow courts to try to distinguish and disturb only those inconsistent convictions that likely resulted from pro-government jury error.